WO2015079906A1 - Thermal-spray material and thermal-spray coating film - Google Patents
Thermal-spray material and thermal-spray coating film Download PDFInfo
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- WO2015079906A1 WO2015079906A1 PCT/JP2014/079869 JP2014079869W WO2015079906A1 WO 2015079906 A1 WO2015079906 A1 WO 2015079906A1 JP 2014079869 W JP2014079869 W JP 2014079869W WO 2015079906 A1 WO2015079906 A1 WO 2015079906A1
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- thermal spray
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- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
- C04B2235/785—Submicron sized grains, i.e. from 0,1 to 1 micron
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
- C04B2235/786—Micrometer sized grains, i.e. from 1 to 100 micron
Definitions
- the present invention relates to a thermal spray material and a thermal spray coating. More specifically, the present invention relates to a thermal spray material containing ceramic particles and a thermal spray coating made of the ceramic material.
- Thermal spraying which is one of the dry coating technologies, is a method in which a particulate thermal spray material made of metal, ceramics, cermet, etc. is melted by a heat source such as a combustion flame or electric energy, and the thermal spray particles are accelerated to accelerate the surface of the substrate. This is a method of forming a film by spraying and depositing on the film.
- thermal spraying technology using ceramic particles as a thermal spray material is relatively economical because of its excellent chemical and mechanical properties such as heat resistance, wear resistance, corrosion resistance, and insulation resistance, which are the characteristics of ceramic materials.
- thermal spraying technology using ceramic particles as a thermal spray material is relatively economical because of its excellent chemical and mechanical properties such as heat resistance, wear resistance, corrosion resistance, and insulation resistance, which are the characteristics of ceramic materials.
- Patent Documents 1 and 2 examples include Patent Documents 1 and 2.
- ceramic materials generally have a high melting point, they are usually sprayed by a high temperature process such as plasma spraying. According to the thermal spraying in this high temperature process, ceramic particles as the thermal spray material grow during flight in the molten state. Therefore, it has been difficult to form a sprayed coating having a fine structure.
- a thermal spray material containing ceramic particles and perform thermal spraying by a low temperature process such as a high-speed flame spraying method.
- a low temperature process is applied to the thermal spraying of ceramic particles, there is a problem that the ceramic particles are not sufficiently melted, and the deposition rate of the thermal spray coating and the thermal spray adhesion rate are lowered.
- the state of the slurry (for example, the dispersed state) is likely to change even in a short time from the preparation of the slurry to being subjected to thermal spraying, which affects the quality of the thermal spray coating to be formed.
- the problem that the thermal spray adhesion rate and the film formation rate are low has not been solved.
- the present invention has been made in view of such a point, and an object of the present invention is to provide a thermal spray material capable of forming a thermal spray coating composed of a ceramic having a dense and fine structure with high productivity. Another object of the present invention is to provide a thermal spray coating made of a ceramic having a dense and fine structure.
- the present invention provides a thermal spray material.
- a thermal spray material is characterized by containing ceramic particles having an average particle diameter of 30 ⁇ m or less and a specific surface area of 0.5 m 2 / g or more.
- the average particle diameter of the ceramic particles can be a size suitable for supplying the thermal spray material as described above.
- the specific surface area is increased so that heat sufficient to soften or melt the sprayed material can be supplied at a spraying temperature at which grain growth can be suppressed.
- the thermal spray material has a complicated shape (structure) in which the surface is three-dimensionally complicated, and the substantial dimension (for example, the thickness of the uneven portion of the surface) is reduced.
- the ceramic melt particles are prevented from growing and can reach the substrate in a sufficiently melted state.
- the thermal spray material which can form the thermal spray coating which consists of ceramics which have a precise
- the “average particle diameter” relating to ceramic particles means, unless otherwise specified, a particle diameter at an integrated value of 50% in a particle size distribution measured by a particle size distribution measuring apparatus based on a laser scattering / diffraction method ( Means 50% volume average particle size; D50).
- the “specific surface area” is determined by measuring the amount of gas (typically nitrogen (N 2 ) gas) physically adsorbed on the surface of the thermal spray material based on the BET method. It means a value obtained by dividing all the external and internal surface areas of the primary particles constituting the thermal spray material by their masses. Such a specific surface area can be measured in accordance with JIS Z 8830: 2013 (ISO 9277: 2010) “Method for measuring specific surface area of powder (solid) by gas adsorption”.
- the ceramic particles are characterized by having a form of secondary particles in which primary particles are three-dimensionally bonded with a gap.
- Such primary particles may be in a more desirable form with an average particle size of less than 6 ⁇ m. That is, the ceramic particle which comprises the thermal spray material disclosed here may be a form comprised from a single porous particle, for example.
- the form of secondary particles in which fine primary particles are combined is preferable.
- the ceramic particles contained in the thermal spray material can be appropriately softened and melted, and a dense thermal spray coating is suitably obtained. Can do.
- a sprayed coating having a finer structure derived from the size of the primary particles can be obtained.
- the thermal spray material which can form the thermal spray coating consisting of ceramics as a thing which has a denser and fine structure with high quality is realized.
- a thermal spray material that can be more easily designed to obtain a thermal spray coating having desired characteristics is provided.
- the “average particle diameter” relating to the primary particles is a value calculated as the diameter (spherical equivalent diameter) of the spherical particles capable of realizing the above specific surface area.
- the average particle diameter (D ave ) of the primary particles can be obtained based on the following formula, where S m is the specific surface area of the ceramic particles (secondary particles) and ⁇ is the density.
- S m is the specific surface area of the ceramic particles (secondary particles)
- ⁇ is the density.
- the “gap” here means a larger space than a space inevitably formed when the primary particles are packed most closely.
- such a “gap” may be a space that is 1.2 times or more the space that is inevitably formed when the primary particles are closest packed.
- the ceramic particles have an average roundness in a plan view of less than 1.5.
- ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are.
- nanometer-sized ceramic particles that are difficult to spheroidize and ceramic particles crushed along the crystal plane have a strong tendency. Therefore, the thermal spray material containing ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame. Ridges, corners, corners, and the like are caught on the surface of the gun, and ceramic particles tend to mesh with each other, which tends to reduce fluidity.
- the average roundness of the ceramic particles is limited to be small as described above, and has an outer shape close to a perfect circle. Therefore, when this thermal spray material is made to flow, it is suppressed that fluidity
- it is easy and stable to supply the thermal spray material to the thermal spraying device and it is possible to suitably supply the thermal spray material to the center of the thermal spray frame and gas, improving the thermal spray efficiency and improving the quality of the thermal spray coating. Improvements can be made.
- the “average roundness” of the ceramic particles is obtained for a planar view image (for example, a secondary electron image) of 100 or more ceramic particles observed by an observation means such as an electron microscope. It means the arithmetic average value of roundness.
- the roundness is a value defined by the following expression from the peripheral length that is the length of the outline of the ceramic particle and the area surrounded by the outline in the plan view image of the ceramic particle.
- the roundness is an index that more easily reflects the smoothness of the surface morphology of the ceramic particles.
- the ceramic particles are characterized in that an average aspect ratio in a plan view is less than 1.4.
- the roundness described above is an index that more easily reflects the surface form among the circularity (can be spherical) of the ceramic particles, and the value becomes more complicated as the contour line in the plan view of the ceramic particles becomes more complicated. Tend to grow. That is, in the ceramic particles having an average roundness closer to 1 as described above, the roundness may more reflect the surface form than the overall form of the ceramic particles. Therefore, in the technology disclosed herein, the form of the ceramic particles is evaluated not only by the roundness but also by the aspect ratio. According to this configuration, it is possible to realize a thermal spray material including ceramic particles whose shape of ceramic particles is closer to a perfect sphere (that is, a perfect circle in plan view) as a whole.
- the “average aspect ratio” means the arithmetic operation of the aspect ratio obtained for a planar view image (secondary electron image, etc.) of 100 or more ceramic particles observed by an observation means such as an electron microscope. Mean value.
- the aspect ratio is defined as a / b, where a is the major axis length and b is the minor axis length of the corresponding ellipse of the ceramic particle.
- the equivalent ellipse is an ellipse having the same area as the ceramic particles and equal primary and secondary moments.
- Such an average aspect ratio can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
- the ceramic particles are characterized by having an average fractal dimension of less than 1.07.
- Fractal dimension (FD) can be an index used to measure the complex morphology of the particle surface.
- FD Fractal dimension
- the ceramic particles have the above average fractal dimension, it is realized as having a smoother surface and improved fluidity of the thermal spray material.
- the supply of the thermal spraying powder to the thermal spraying apparatus can be further stabilized, and the spraying material can be easily put into the frame or the working gas central part.
- the thermal spraying material can suitably receive the effects of heating and acceleration by the thermal spraying process, improving the thermal spraying efficiency and improving the quality of the coating film to be formed.
- the angle of repose is less than 35 °.
- the angle of repose is an index that can indicate the fluidity of the powder, and since it depends on the particle size (average particle diameter) of the powder, etc.
- the angle of repose can be increased in the case of a powder having a small particle size and poor fluidity. According to such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 ⁇ m has high fluidity, and it is possible to provide a thermal spraying material capable of forming a thermal spray coating with higher productivity.
- the “repose angle” is a bottom calculated from the diameter and height of the conical deposit generated by dropping the sprayed material from a funnel having a certain height onto a horizontal substrate. Means a corner.
- Such angle of repose can be measured in accordance with the provisions of JIS R 9301-2-2: 1999 “Alumina powder physical property measurement method-2: angle of repose”.
- the ceramic particles are selected from the group consisting of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite. It is characterized by containing a seed or two or more ceramic materials. According to this configuration, for example, there is provided a thermal spray material capable of forming a thermal spray coating having a function corresponding to the function of a single material of the above ceramic material or the function of a material obtained by mixing or combining two types of ceramic materials. Is done.
- the invention disclosed herein provides a thermal spray coating in which thermal spray particles made of a ceramic material are deposited on a substrate.
- the thermal spray coating is characterized in that the average particle diameter of the thermal spray particles in a cross section perpendicular to the surface of the substrate is less than 5 ⁇ m. According to such a configuration, even if the sprayed coating is made of a ceramic material, a fine and dense sprayed coating having a particle diameter as described above can be realized.
- the “average particle diameter” relating to the spray particles is a value obtained by image analysis of an observation image of the structure in a cross section substantially perpendicular to the base material of the spray coating. Specifically, the observation image obtained by observing a cross-sectional structure substantially perpendicular to the base material of the thermal spray coating with a microscope with a predetermined magnification is binarized to separate the pore portion and the solid phase portion. By analyzing this using image analysis software, it is a value obtained as an arithmetic average value of equivalent circle diameters for 100 or more sprayed particles.
- the invention disclosed herein also provides a substrate with a thermal spray coating, in which the above thermal spray coating is provided on the surface of the substrate.
- a base material with a thermal spray coating may be capable of imparting a function close to the bulk of the ceramic material to the base material since the surface of the base material is coated with a ceramic material having a fine and dense structure.
- FIG. 1 is a diagram illustrating a scanning electron microscope (SEM) image of a thermal spray material according to an embodiment.
- FIG. 2 is a partially enlarged view of FIG.
- FIG. 3 is a diagram illustrating a scanning electron microscope (SEM) image of a cross section of the thermal spray coating according to an embodiment.
- FIG. 4 is a diagram illustrating a scanning electron microscope (SEM) image of a conventional thermal spray material.
- thermal spray material of the present invention will be described with reference to the drawings as appropriate. It should be noted that matters other than matters specifically mentioned in the present specification (forms of thermal spray material, etc.) and matters necessary for carrying out the present invention (for example, thermal spraying method and thermal spraying device using such thermal spray material, etc.) General matters relating to thermal spraying) can be understood as design matters of those skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
- the thermal spray material disclosed here essentially includes ceramic particles having an average particle diameter of 30 ⁇ m or less and a specific surface area of 0.5 m 2 / g or more. That is, the thermal spray material is mainly composed of ceramic particles having a very large specific surface area. Specifically, for example, since the specific gravity of silica (SiO 2 ) is 2.2 [g / ml], the specific surface area of the spherical silica particles having a radius of r [m] is 1.36 / r ⁇ It is represented by 10 ⁇ 6 [m 2 / g].
- the specific surface area of a true spherical silica particle having a radius of 30 [ ⁇ m] is represented by 1.36 / 900 ⁇ 10 6 [m 2 / g].
- the specific surface area of the thermal spray material disclosed herein is defined to be 0.5 [m 2 / g] or more.
- the thermal spray material disclosed herein has a complicated shape (structure) in which the surface form is complicated three-dimensionally. That is, substantial dimensions (for example, the thickness of the uneven portions on the surface) can be significantly reduced without being restricted by the average particle diameter of the thermal spray material itself.
- a ceramic material having a high melting point can efficiently absorb heat from a heat source such as a relatively low temperature spraying frame to achieve sufficient softening and melting.
- a thermal spray material capable of forming a thermal spray coating made of ceramics with good adhesion to a substrate is provided. Furthermore, the structure of the sprayed coating formed can be fine without depending on the average particle size of the ceramic particles.
- the specific surface area of the ceramic particles is not particularly limited as long as it is in the above range, but it is desirable that the specific surface area be larger. For example, it can be set to 0.8 m 2 / g or more, preferably 1 m 2 / g or more, and more preferably 10 m 2 / g or more.
- the average particle size of the ceramic particles can be a size suitable for supplying the thermal spray material as described above. Therefore, for example, even when such a thermal spray material is supplied to a high-speed thermal spray frame, the ceramic particles have an appropriate size and weight, and thus are not easily repelled by the thermal spray frame. Therefore, also in this respect, thermal spraying can be performed while maintaining a high thermal spraying adhesion rate and film formation rate. Moreover, since it is possible to maintain the supply property of the thermal spray material high, it is possible to suppress the problem of deterioration in the quality of the thermal spray coating due to the non-uniform supply of the thermal spray material.
- the average particle size of the ceramic particles is not particularly limited as long as it is about 30 ⁇ m or less, and the lower limit of the average particle size is not particularly limited. In the case of a smaller one, for example, it can be 2 ⁇ m or less, preferably 1 ⁇ m or less, for example 400 nm or less. For example, specifically, so-called nanoparticles having an average particle diameter of 100 nm or less can be used. However, for example, in consideration of handling when forming such ceramic particles, the lower limit of the average particle diameter is preferably 100 nm or more, more preferably 1 ⁇ m or more, for example, 5 ⁇ m or more. Illustrated.
- the thermal spray material Normally, when fine ceramic particles having an average particle diameter of less than about 6 ⁇ m, for example, are used as the thermal spray material, the fluidity decreases with an increase in specific surface area, and the film forming ability decreases. Furthermore, due to its small mass, it may be difficult to fly such a thermal spray material on a frame or jet stream.
- the thermal spray material disclosed here a plurality of particles are three-dimensionally bonded with a gap to primary particles having an average particle diameter of less than 6 ⁇ m. As a result, weighting is achieved so as not to be repelled from a frame, a jet stream, or the like while substantially maintaining the form of the primary particles. This can provide a completely new thermal spray material that has both the advantage of using ceramic particles having a smaller average particle diameter and the advantage of using ceramic particles having a larger average particle diameter.
- the component which can become a film formation component at the time of formation of the thermal spraying film by thermal spraying among the structural components of the above thermal spraying material is mainly said ceramic particle.
- “mainly” means that the ceramic particles occupy 95% by mass or more of the film forming component.
- the ceramic particles can occupy 98% by mass or more, more preferably 99% by mass or more, for example, 99.5% by mass or more, and substantially 100% by mass.
- the composition of the ceramic particles is not particularly limited.
- it may be a ceramic material (oxide ceramic) made of oxide, or a ceramic material made of non-oxide such as carbide, nitride, halide, apatite.
- oxide ceramics are not particularly limited and may be oxides of various metals. Examples of metal elements constituting such oxide ceramics include metalloid elements such as B, Si, Ge, Sb, and Bi, Mg, Ca, Sr, Ba, Zn, Al, Ga, In, Sn, and Pb.
- the oxide-based ceramic disclosed herein preferably contains a halogen element such as F, Cl, Br, or I in addition to the above metal elements.
- the oxide ceramics include, for example, alumina, zirconia, yttria, chromia, titania, cobaltite, magnesia, silica, calcia, ceria, ferrite, spinel, zircon, nickel oxide, silver oxide, copper oxide, Zinc oxide, gallium oxide, strontium oxide, scandium oxide, samarium oxide, bismuth oxide, lanthanum oxide, lutetium oxide, hafnium oxide, vanadium oxide, niobium oxide, tungsten oxide, manganese oxide, tantalum oxide, terpium oxide, europium oxide, oxide Neodymium, tin oxide, antimony oxide, antimony-containing tin oxide, indium oxide, tin-containing indium oxide, zirconium oxide aluminate, zirconium oxide silicate, hafnium oxide aluminate, acid Hafnium silicate, titanium silicate oxide, lanthanum silicates, lan
- Non-oxide ceramics include, for example, carbides such as silicon carbide and boron carbide, nitrides such as silicon nitride and aluminum nitride, forsterite, steatite, cordierite, mullite, barium titanate, lead titanate. , Lead zirconate titanate, Mn—Zn ferrite, Ni—Zn ferrite, sialon and other composite materials, hydroxyapatite, phosphate compounds such as calcium phosphate, and the like. Furthermore, any one of these ceramic materials may constitute ceramic particles alone, or two or more thereof may be combined to constitute ceramic particles. For example, when two or more kinds of ceramic materials are included in the ceramic particles, some or all of these ceramic materials may form a composite oxide.
- Such composite ceramic particles include, for example, composites such as yttria stabilized zirconia, partially stabilized zirconia, gadolinium doped ceria, lanthanum doped lead zirconate titanate, and the above sialon. An oxide etc. are mentioned.
- ceramic materials for example, other elements (for example, transition metal elements, elements other than those exemplified above such as Na, K, Rb, etc.) are introduced for the purpose of adjusting the color tone of the formed thermal spray coating. Alternatively, other elements may be introduced for the purpose of enhancing functionality. A part of the elements constituting the ceramic material may be included in the form of ions or complexes. Among these ceramic materials, it is more preferable to include any of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite.
- the purity of these ceramic particles is not particularly limited. However, for example, in the case of an application for forming a thermal spray coating having a higher functionality, it is preferable to avoid mixing an unintended substance (element), and the higher the purity of the thermal spray material is preferable. From this viewpoint, it is preferable that the ceramic particles have a higher purity.
- the purity is preferably 95% by mass or more, further 99% by mass or more, more preferably 99.9% by mass or more, for example, 99.99% by mass or more.
- components other than ceramic particles may be included, or may not be included.
- the sprayability of the sprayed material is improved as described above, it may not be prepared in the form of a slurry (including suspension, ink, and base). That is, the component which cannot become a film formation component does not need to be substantially contained.
- an additive such as a dispersion medium for dispersing the ceramic particles and a dispersant for improving dispersibility in the dispersion medium is included in order to prepare the thermal spray material in a slurry state.
- Typical examples of such a dispersion medium include water and a mixed solvent of water and a water-affinity alcohol.
- a material other than such ceramics typically, a particulate material such as metal powder
- a material other than such ceramics typically, a particulate material such as metal powder
- the specific structure and manufacturing method of the ceramic particles having an increased specific surface area as described above are not particularly limited.
- the specific surface area as described above may be realized by using ceramic particles having a porous structure, and the average particle diameter may be adjusted. Or you may make it manufacture the ceramic particle which implement
- ceramic particles having the following configuration may be prepared.
- FIG. 1 is an SEM image illustrating an embodiment of such ceramic particles
- FIG. 2 is an enlarged image thereof.
- the average particle diameter of the primary particles is not particularly limited, but is preferably less than 6 ⁇ m, for example.
- the average particle diameter of the primary particles is preferably 5 ⁇ m or less, and more preferably 1 ⁇ m or less, for example.
- the average particle diameter of the primary particles is further preferably 500 nm or less, for example, nanoparticles of 100 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 10 nm or less can be obtained.
- the average particle diameter of the primary particles fine, for example, it can be softened or melted at a temperature lower than the melting point of the ceramic material itself constituting the thermal spray material. This can be a completely new finding that has not been anticipated. Therefore, such a thermal spray material can be particularly suitably used for, for example, a thermal spraying method using a low temperature process.
- a thermal spray coating made of ceramic can be formed with high quality, for example, as a dense one with good adhesion.
- the low temperature process can reliably prevent the nanometer-sized primary particles from becoming coarse.
- the thermal spray coating formed by such a low temperature process can have a finer and denser structure derived from the size of the primary particles in the ceramic particles. Thereby, for example, it may be possible to form a thermal spray coating having characteristics close to the bulk of the ceramic material.
- the average particle size of the primary particles relative to the average particle size of the ceramic particles is The smaller one is preferable because ceramic particles that can better reflect the above-described advantages can be realized.
- the average particle diameter of ceramic particles is Ra and the average particle diameter of primary particles is ra
- the ratio ra / Ra is smaller.
- the value of ra / Ra is preferably 0.1 or less, more preferably 0.05 or less, for example, 0.01 or less, and even more preferably 0.005 or less.
- a thermal spray material composed of secondary particles formed by bonding primary particles is also known.
- the conventional granulated-sintered particles have a relatively large average particle diameter of primary particles (for example, 6 ⁇ m or more). It was not considered at all.
- the specific surface area of conventional granulated-sintered particles is typically about 0.4 m 2 / g or less, and cannot be realized to be 0.5 m 2 / g or more. From this point of view, the characteristics of the morphology of the ceramic particles disclosed herein can be a novel one that has not been seen so far.
- Such ceramic particles to which finer primary particles are bonded are not particularly limited in the production method.
- it can be produced using a known granulation method such as dry granulation or wet granulation.
- granulation methods include, for example, rolling granulation method, fluidized bed granulation method, stirring frame granulation method, crushing granulation method, melt granulation method, spray granulation method, microemulsion granulation method Etc.
- a spray granulation method is a preferable granulation method.
- such ceramic particles can be prepared by the following procedure as an example. That is, first, ultrafine ceramic particles (for example, nanoparticles having a diameter of several nanometers (eg, 1 nm) to 100 nm) that can form primary particles are prepared, and the surface thereof is stabilized with a protective agent or the like. . Then, the stabilized ultrafine particles of the ceramics are dispersed in an appropriate solvent together with spacer ultrafine particles made of, for example, an organic material, a binder, or the like as necessary to prepare a spray solution.
- ultrafine ceramic particles for example, nanoparticles having a diameter of several nanometers (eg, 1 nm) to 100 nm
- spacer ultrafine particles made of, for example, an organic material, a binder, or the like as necessary to prepare a spray solution.
- the primary particles can be dispersed in the solvent using, for example, a mixer such as a homogenizer or a blade-type stirrer, a disperser, or the like. Then, by spraying this spray liquid using an ultrasonic sprayer or the like, droplets of an appropriate size including a plurality of ceramic ultrafine particles are formed. Such droplets are, for example, placed in an air stream and passed through a continuous furnace. Then, while being transported in the continuous furnace, the droplets are dried in a low temperature zone provided relatively upstream in the furnace to remove the solvent component, and then fired in a high temperature zone provided relatively downstream in the furnace. Is done. Thereby, ceramic particles in the form of secondary particles in which the primary particles are bonded with a gap can be obtained.
- a mixer such as a homogenizer or a blade-type stirrer, a disperser, or the like.
- droplets of an appropriate size including a plurality of ceramic ultrafine particles are formed.
- Such droplets are, for example, placed in an
- the average particle diameter of the ceramic particles obtained is considerably smaller than the size of the droplets due to the disappearance of components other than the ceramic and the sintering of the ceramic ultrafine particles due to firing during the period from drying to sintering.
- the average particle diameter of these ceramic particles and primary particles and the size and ratio of the gaps formed between the primary particles can be appropriately designed according to the desired form of the ceramic particles.
- ceramic particles having the following configuration may be prepared. That is, it is composed of ceramic particles having a microporous structure typified by a zeolite structure and a mesoporous structure.
- a so-called mesoporous material called a microporous structure made of a ceramic material having pores (mesopores) having a diameter of 2 nm to 50 nm can be used.
- Such a microporous structure uses, for example, a structure-defining amphiphile (typically, a block copolymer, a surfactant, etc.) as a template, and uses a self-assembly process or a sol-gel process on its surface. It can be formed by forming a microporous structure made of a ceramic precursor such as an alkoxide of the target metal and then removing the template.
- the ceramic material having such a microporous structure is not particularly limited, and examples thereof include mesoporous silica, mesoporous titania, mesoporous alumina, and mesoporous aluminosilicate.
- a ceramic material having pores (micropores) having a diameter of 2 nm or less and pores (macropores) having a diameter of 50 nm or more. Etc. may also be included.
- the thermal spray material disclosed herein preferably contains ceramic particles having an average roundness of less than 1.5 (for example, 1 or more and less than 1.5).
- the average roundness is employed as an index that can indirectly represent the average sphericity of ceramic particles having a relatively small particle diameter.
- Means roundness When the ceramic particles are viewed in plan from an arbitrary direction, Means roundness. Therefore, this average roundness does not necessarily mean that the ceramic particles are two-dimensionally close to a perfect circle, but is essentially three-dimensionally close to a perfect sphere. Is intended.
- thermal spray materials ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are.
- the ceramic particles as a pulverized product were crushed along the crystal plane, and the tendency was strong.
- the thermal spray material made of ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame.
- the thermal spray material having the form of the secondary particles disclosed herein may have a form reflecting the high crystallinity of the ceramic material, for example, an outer shape such as a prismatic shape or a lump shape.
- high fluidity can be secured by satisfying the above average roundness.
- the average roundness can be an index that can reflect the average sphericity at a level that cannot be expressed by an index such as an average aspect ratio.
- the thermal spray material that can improve the fluidity in the supply device and the supply capability to the thermal spray gun during thermal spraying and can suitably supply the thermal spray material to the center of the thermal spray frame, gas, etc. Realized.
- the average roundness of such ceramic particles is preferably as close to 1 as possible, and may be a value of 1 or more.
- the average roundness is preferably 1.4 or less, more preferably 1.2 or less, and may be 1.15 or less, for example, 1.1 or less.
- the average aspect-ratio is less than 1.4. This is because, as described above, in ceramic particles having an average roundness closer to 1, the roundness may reflect the surface morphology more than the overall morphology of the ceramic particles. In other words, in the case of evaluating ceramic particles that are close to a perfect circle, the roundness described above becomes more complex as the contour line in the plan view of the ceramic particles becomes more complex at a micro level. It tends to be larger than the degree of change of the outer shape.
- the outer shape of the ceramic particles by the aspect ratio in addition to the roundness, it is possible to obtain ceramic particles whose overall outer shape is closer to a perfect sphere, that is, closer to a perfect circle in plan view. it can.
- the average aspect ratio is preferably 1.3 or less, and more preferably 1.2 or less in consideration of the fluidity of the thermal spray material. Further, for example, it can be set to 1.15 or less, and is preferably 1 or closer to 1.
- an average fractal dimension is preferably less than 1.07. This is because such ceramic particles may have a complicated surface morphology at a micro level. Therefore, by defining the complicated shape of the particle surface with more various indexes, the outer shape of the ceramic particle can be made closer to a true sphere.
- the fractal dimension is an index that is widely used to measure the complex morphology of individual particle surfaces, and the average fractal dimension is a suitable index for indicating the smoothness of the surface of ceramic particles disclosed herein. possible. By defining the average fractal dimension to be less than 1.07, it is possible to realize a thermal spray material with further improved fluidity.
- the average fractal dimension is preferably 1.05 or less and more preferably 1.03 or less in consideration of the fluidity of the thermal spray material. Furthermore, for example, it can be set to 1.02 or less and 1.01 or less, and is desirably 1 or closer to 1.
- the angle of repose is less than 35 °.
- the angle of repose can be one of the indexes that have been widely adopted to show the fluidity of powders.
- it may be an index that can actually reflect the spontaneous fluidity when the thermal spray material is conveyed in the supply apparatus and the thermal spray apparatus. Therefore, by defining the angle of repose to be small, a spray material having high fluidity can be realized. As a result, it can be a thermal spray material capable of forming a homogeneous thermal spray coating with higher productivity.
- the angle of repose is preferably 34 ° or less, and more preferably 32 ° or less.
- the angle may be 30 ° or less.
- the lower limit of the angle of repose is not particularly limited. However, if the angle of repose is too small, the sprayed material may be easily scattered or the supply amount of the sprayed material may be difficult to control. Therefore, as an approximate guide, the angle of repose is exemplified as 20 ° or more.
- the thermal spray material disclosed herein preferably has a flow function of 3 or more.
- the angle of repose is an index that can evaluate the fluidity of the thermal spray material in a no-load state.
- this flow function evaluates the flow characteristics by measuring the shear stress in a compacted state of the thermal spray material, and can be an index that can more practically express the handling property of the thermal spray material. Therefore, even with such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 ⁇ m has high fluidity, and it is possible to provide a thermal spraying material that can form a thermal spray coating with higher productivity.
- the “flow function” is a value called a so-called Relative Flow Index (RFI), and a predetermined amount of thermal spray material is placed in a container having an inner diameter of 50 mm. Measure the maximum principal stress and uniaxial collapse stress of the thermal spray material when a shearing force of 9 kPa is applied to the thermal spray material under humidity, and divide the measured value of the maximum principal stress by the measured value of the uniaxial collapse stress. This is the value obtained by. The larger the flow function, the better the fluidity of the sprayed material.
- RFI Relative Flow Index
- the thermal spray material provided by the technique disclosed herein maintains a relatively large average particle diameter of the ceramic particles contained therein, and thus, for example, the heat source supplyability to the thermal spray frame or the like ( Including fluidity). Further, since the specific surface area is defined to be extremely large, it can be sufficiently softened and melted at a lower temperature, and a fine structure can be realized. Therefore, it can be a thermal spray material capable of forming a thermal spray coating having a dense and fine structure with high productivity.
- such a thermal spray material can be suitably realized as a suitable form, for example, including ceramic particles as secondary particles formed by bonding finer primary particles.
- it may be ceramic particles in a form in which nanometer-sized primary particles are bonded.
- the ceramic particles as such secondary particles it is possible to provide a sufficient gap between the finer primary particles, and the ceramic particles constitute secondary particles while maintaining the form of the primary particles. be able to. Therefore, for example, by using such a thermal spray material for thermal spraying, a high-quality thermal spray coating having the same characteristics as the case of thermal spraying using a thermal spray material having dimensions (for example, nanometer size) corresponding to primary particles is formed. be able to.
- thermal spraying at a lower temperature is possible.
- thermal spraying in the same manner as when using a thermal spray material having a dimension (for example, micrometer size) corresponding to the secondary particles.
- a thermal spray material can be supplied to a thermal spraying apparatus with good fluidity, and a thermal spray coating with high efficiency and good adhesion can be formed at a high film forming speed.
- a sprayed coating obtained by spraying such a sprayed material by, for example, a high-speed flame spraying method is a sprayed coating in which sprayed particles made of a ceramic material are deposited on a base material, and the cross section is perpendicular to the surface of the base material.
- the average particle diameter of the spray particles is less than 5 ⁇ m, fine molten particles may be densely deposited.
- the particle size of the spray particles is preferably 4 ⁇ m or less, more preferably 3 ⁇ m or less, further preferably 1 ⁇ m or less, and even more preferably 100 nm or less. Therefore, it may have characteristics comparable to the bulk of the thermal spray material.
- thermo spray coating excellent in electrical characteristics such as denseness and insulation, corrosion resistance, and environmental barrier properties. Therefore, a film-formed product provided with such a thermal spray coating can be suitably applied to a wide variety of uses by being formed using a thermal spray material containing ceramic particles having desired characteristics.
- a sprayed coating exhibiting high electrical insulation, wear resistance, and corrosion resistance can be obtained, and therefore, it can be suitably used as a protective coating for various members.
- a thermal spray coating exhibiting high plasma erosion resistance can be obtained, and therefore, it can be suitably used as a protective coating inside a chamber of a semiconductor device manufacturing apparatus or the like.
- the resulting sprayed coating is preferable because the plasma erosion resistance is further enhanced.
- thermal spray coating that is hard and has excellent ion conductivity can be obtained, so that the solid oxide fuel cell (Solid Oxide Fuel Cel1: SOFC) solid It can be suitably used as an electrolyte or the like.
- the thermal spray coating according to a desired use can be suitably formed with the thermal spray coating material disclosed here.
- the above-mentioned thermal spray material can be applied to various thermal spraying methods without particular limitation.
- it can be applied to a thermal spraying method in a high temperature process in which the temperature of the heat source is 2500 ° C. or higher, such as a plasma welding method, as in the past.
- a thermal spraying method for example, when using a thermal spray material containing ceramic particles that are not in the form of secondary particles, the thermal spray material can be sufficiently softened and melted, and high-quality thermal spraying can be performed.
- the plasma spraying method is a spraying method using a plasma flame as a thermal spraying heat source for softening or melting a thermal spray material.
- the plasma spraying method includes a general coating technique in which a thermal spray material is put into this plasma jet, heated and accelerated, and deposited on a substrate by deposition.
- Plasma spraying methods include atmospheric plasma spraying (APS) performed in the atmosphere, low pressure plasma spraying (LPS) performed at a pressure lower than atmospheric pressure, and pressure higher than atmospheric pressure. It may be an embodiment such as high pressure plasma spraying in which plasma spraying is performed in a pressure vessel.
- APS atmospheric plasma spraying
- LPS low pressure plasma spraying
- the thermal spray material is heated and accelerated by a plasma jet at about 2500 ° C. to 10000 ° C. to cause the thermal spray particles to collide with the substrate at a speed of about 300 m / s to 600 m / s. Can be deposited.
- the thermal spray material including ceramic particles formed by bonding finer primary particles
- it can be sprayed at a temperature lower than the melting point of the ceramic material itself constituting the ceramic particles contained therein, for example, It is preferable to apply to a thermal spraying method in a low-temperature process where the temperature of the heat source is about 2500 ° C. or less (less than 2500 ° C.) because the advantages are manifested. Therefore, such a thermal spray material can be preferably applied to a thermal spraying method by a low temperature process represented by, for example, a high-speed flame spraying method or a foam spraying method.
- such a thermal spray material can suitably realize a softened or molten state even when the ceramic particles are at a lower temperature.
- the thermal spray material adheres to the base material with good adhesion and becomes finer.
- a sprayed coating can be formed.
- the spraying speed can be adjusted as appropriate using, for example, about 300 m / s or more and 2000 m / s or less.
- Examples of the high-speed flame spraying method include an oxygen-flammable high-speed flame (HVOF) thermal spraying method, a warm spray thermal spraying method, and an air-flammable (High Velocity Air flame: HVAF) high-speed flame spraying method.
- HVOF oxygen-flammable high-speed flame
- the HVOF spraying method is a kind of flame spraying method in which a combustion flame in which fuel and oxygen are mixed and burned at high pressure is used as a heat source for spraying. By increasing the pressure in the combustion chamber, a high-temperature (which may be supersonic) high-temperature gas flow is ejected from the nozzle while being a continuous combustion flame.
- the HVOF thermal spraying method includes a general coating technique in which a thermal spray material is put into this gas flow, and heated and accelerated to deposit it on a substrate to obtain a thermal spray coating.
- the thermal spray material is melted and accelerated with a jet of a supersonic combustion flame of 1800 ° C. to 2500 ° C., so that the thermal spray particles can be obtained at a high speed of 500 m / s to 1000 m / s. It can be deposited by colliding with the material.
- the fuel used in high-speed flame spraying may be a hydrocarbon gas fuel such as acetylene, ethylene, propane, or propylene, or a liquid fuel such as kerosene or ethanol. Further, the higher the melting point of the thermal spray material, the higher the temperature of the supersonic combustion flame is preferable. From this viewpoint, it is preferable to use gas fuel.
- the warm spray spraying method is the above-described HVOF spraying method in which the temperature of the combustion flame is lowered by mixing the combustion flame with a cooling gas composed of nitrogen or the like at a room temperature. This is a technique for forming a sprayed coating.
- the thermal spray material is not limited to a completely melted state.
- a thermal spray material that is partially melted or softened below the melting point can be sprayed. According to this warm spray spraying method, for example, the sprayed material is melted and accelerated by a jet of a supersonic combustion flame at 1000 ° C.
- the HVAF thermal spraying method is a thermal spraying method in which air is used in place of oxygen as a combustion support gas in the HVOF thermal spraying method.
- the spraying temperature can be lowered as compared with the HVOF spraying method.
- a thermal spray material is melted and accelerated by a jet of a supersonic combustion flame at 1600 ° C. to 2000 ° C., so that the thermal spray particles collide with a substrate at a high speed of 500 m / s to 1000 m / s and are deposited.
- the thermal spray material disclosed herein thermal spraying at a temperature lower than the melting point of the ceramic material constituting the ceramic particles contained in the thermal spray material is enabled.
- the As a result it is possible to form a film made of ceramics having a dense and fine structure by realizing sufficient melting while suppressing grain growth of ceramic particles having a three-dimensionally complicated structure.
- the spraying temperature at a lower temperature is, for example, about 10 ° C. to 4000 ° C., for example, about 50 ° C. to 350 ° C. lower than the melting point.
- a thermal spray coating made of alumina having a melting point of 2050 ° C. is formed at a thermal spray temperature of 2000 ° C. or lower, more specifically 1700 ° C. or lower. It is possible.
- a thermal spray coating made of yttria stabilized zirconia having a melting point of 2600 ° C. or higher can be sprayed to 2550 ° C. or lower, more specifically 2300 ° C. or lower. It is possible to form at temperature.
- a thermal spray coating made of mullite having a melting point of 1915 ° C. can be formed at a thermal spray temperature of 1900 ° C. or lower, more specifically 1860 ° C. or lower. It is said.
- the thermal spray material disclosed herein can maintain high fluidity without depending on the average particle diameter, the thermal spray material can be efficiently and smoothly supplied to the thermal spraying device, and high-quality thermal spraying can be performed. A film can be formed with good productivity. Therefore, the method of supplying the spray material to the spraying device is not particularly limited. For example, it is preferable to perform the axial feed method, that is, to supply the thermal spray material in the same direction as the axis of the jet flow generated in the thermal spraying apparatus. From the viewpoint that the thermal spray material is less likely to adhere to the thermal spraying device, the thermal spray material can be kept in a more fluid state by supplying the thermal spraying material to the thermal spraying device by an axial feed method, and a uniform thermal spray coating can be obtained. It is preferable because it can be formed efficiently.
- the spraying distance can be appropriately set depending on the spraying method and the spraying apparatus.
- the distance from the nozzle tip to the substrate is preferably about 30 mm or more and 200 mm or less. If the spraying distance is too short, the thermal spray heat source is close to the base material, and therefore the base material may be altered or deformed, which is not preferable. If the spraying distance is too long, the speed of the molten particles is reduced and the cooling proceeds, so that sufficient adhesion may not be obtained, which is not preferable.
- the spraying distance is within the above range, for example, the sufficiently heated sprayed particles can reach the substrate at an appropriate speed while maintaining the temperature, so that a sprayed coating having a dense and good adhesion is obtained. be able to.
- the base material which is a sprayed material What consists of various materials can be used.
- various materials include various metals or alloys. Specifically, for example, aluminum, aluminum alloy, iron, steel, copper, copper alloy, nickel, nickel alloy, gold, silver, bismuth, manganese, zinc, zinc alloy and the like are exemplified.
- steels represented by various SUS materials which may be so-called stainless copper
- heat resistant alloys represented by Inconel, Invar, Kovar, etc. which have a relatively large coefficient of thermal expansion among metal materials that are widely used.
- a base material made of a low expansion alloy represented by, etc., a corrosion resistant alloy represented by Hastelloy, etc., an aluminum alloy represented by 1000 series to 7000 series aluminum alloys useful as a lightweight structural material, etc. is disclosed herein.
- This method is preferable in that a finely sprayed coating having good adhesion can be formed suitably, and the advantages of the present invention can be clarified.
- thermal spray materials of Samples 1 to 6 are all composed of alumina particles having an average particle diameter of 24 ⁇ m.
- the thermal spray material of Sample 1 is manufactured by the melt-pulverization method, and the average particle diameter of primary particles made of alumina (Al 2 O 3 ) is 24 ⁇ m.
- the thermal spray materials of Samples 2 to 6 are composed of alumina secondary particles having the above average particle diameter by forming and sintering primary particles made of alumina each having the average particle diameter shown in the table. Yes.
- the thermal spray materials of Samples 7 and 8 contain particles having an average particle size of 24 ⁇ m, each composed of yttria (Y 2 O 3 ) and 8% Yttria-Stabilized Zirconia (8% YSZ). . These particles also form secondary particles having the above average particle diameter by granulating and sintering primary particles having the average particle diameter shown in the table.
- the sprayed material was prepared by the following procedure by the melt-pulverization method. That is, first, raw material powder is blended so as to obtain a target ceramic (in this case, Al 2 O 3 ), the raw material powder is heated and melted, and then cooled to prepare a solidified product (ingot). .
- the solidified product was pulverized by mechanical means and classified as necessary to obtain a thermal spray material.
- the alumina particles contained in the thermal spray material of Sample 1 obtained by this melt-pulverization method were relatively dense and strong, and had a square or lump shape with an edge characteristic of the pulverized powder. .
- the sprayed material was prepared by the granulation-sintering method according to the following procedure. That is, first, a ceramic (primary particles, in this case, ultrafine particles such as Al 2 O 3 , Y 2 O 3 , 8% YSZ) having a predetermined average particle diameter is subjected to surface treatment, together with a binder (PVA: polyvinyl alcohol). A slurry is prepared by thoroughly mixing and dispersing in a solvent (such as a mixed solution of water and alcohol). Next, the slurry is granulated into droplets using a spray granulator and a dry sintering furnace, and dried and sintered to obtain ceramic particles (secondary particles). And it was set as the thermal spray material by classifying this ceramic particle as needed.
- a ceramic primary particles, in this case, ultrafine particles such as Al 2 O 3 , Y 2 O 3 , 8% YSZ
- PVA polyvinyl alcohol
- a slurry is prepared by thoroughly mixing and dispersing in a solvent
- the ceramic particles contained in the thermal spray materials of Samples 2 to 8 obtained by the granulation-sintering method are substantially the same as shown in FIGS. 1 and 2, in which very fine primary particles are bonded to each other. It constitutes spherical secondary particles.
- FIG. 1 is an image obtained by observing the thermal spray material of Sample 6 with a scanning electron microscope described later.
- FIG. 2 is an image obtained by observing one ceramic particle in FIG. 1 at a high magnification.
- very fine primary particles were observed in detail, they had a prismatic or massive shape with a specific crystal plane developed.
- the specific surface area of the ceramic particles was measured based on the BET method using nitrogen gas as an adsorbed gas, using a flow type specific surface area automatic measuring device (manufactured by Shimadzu Corporation, Flowsorb II 2300). Specifically, after putting ceramic particles as a sample into a sample tube, the sample is cooled, nitrogen gas is introduced into the sample tube, and an adsorption / desorption isotherm by a constant volume method gas adsorption method is prepared.
- the average aspect ratio of the ceramic particles is a planar view image (magnification 1000) obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). ⁇ 2000 times) was calculated by calculating the arithmetic average of the aspect ratios measured for 100 or more ceramic particles using image analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.).
- the aspect ratio specifies the contour of the ceramic particle from the contrast of the SEM image, and the major axis length of the corresponding ellipse (the ellipse having the same area and the same primary and secondary moments) is the major axis a and the minor axis length. This is a value obtained by determining the aspect ratio defined by a / b from these values, where the minor axis is b.
- the measurement result of the average aspect ratio of the ceramic particles is shown in the column of “Average aspect ratio” in Table 1.
- the average fractal dimension of the ceramic particles is the image of a planar view image obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). Using an analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.), the arithmetic average value of the fractal dimension measured for 100 or more ceramic particles was calculated. SEM analysis conditions were as follows: magnification: 2000 times, bit depth: 8, scanning speed: 80/100 s. In addition, the SEM image used for the measurement of the fractal dimension is prepared to realize a resolution in which the peripheral length of the ceramic particles is 30 pixels or more (preferably 1280 pixels or more.
- the angle of repose of the thermal spray material is the same as that of the thermal spray material of Samples 1-8.
- B. D. This is a value obtained by applying to a powder property measuring instrument (ABD-72, manufactured by Tsutsui Science Instruments Co., Ltd.).
- the measurement results of the repose angle of the thermal spray material are shown in the column “Repose angle” in Table 1.
- [Flow function] For reference, the thermal spray material of Sample 6 was measured with a powder fluidity analyzer (Powder Rheometer FT4, manufactured by Freeman Tchnology). As a result, the flow function of the thermal spray material of Sample 6 was 9.2.
- the spraying material prepared above was sprayed by the HVOF spraying method, which is a low-temperature process, to evaluate the film formability of the sprayed coating by the spraying material.
- the thermal spraying conditions were as follows. That is, first, an SS400 steel plate (70 mm ⁇ 50 mm ⁇ 2.3 mm) was prepared as a base material, and the surface was roughened by performing a blasting process using a # 40 alumina grid. A commercially available high-speed flame sprayer (Praxair / TAFA, JP-5000) was used for HVOF spraying.
- the upper limit of the flame temperature is about 2000 ° C., which is much lower than the melting point of the ceramic used for the thermal spray material.
- the thermal spray material was supplied to the burner chamber of the thermal sprayer at a supply rate of about 15 g / min in a dry powder state using a powder feeder (TechnoServ, AM-30).
- the thermal sprayer was supplied with acetylene gas as a fuel gas at a flow rate of 75 L / min and oxygen gas as a combustion aid at a flow rate of 230 L / min.
- a supersonic jet of about 1500 ° C. to 2500 ° C.
- the unit ( ⁇ m / pass) representing the film formation rate is formed by a single spraying operation (1 pass) performed by the spraying device (spraying gun) along the operating direction of the spraying device or the object to be sprayed (base material).
- the thickness ( ⁇ m) of the sprayed coating that can be obtained is shown.
- the size (equivalent circle diameter) of the thermal spray particles constituting the solid phase portion was measured.
- the measurement of the size of the thermal spray particles constituting the thermal spray coating was obtained by observing with a scanning electron microscope (Scanning Electron Microscope: SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N) 2000.
- Fig. 3 illustrates an SEM image of the cross-sectional structure of the sprayed coating obtained by spraying the sprayed material of Sample 5.
- the observation image used for the measurement of the size of the spray particles constituting the coating is, for example, a resolution in which the peripheral length of the ceramic particles is 30 pixels or more as shown in FIG. Preferably.
- the thermal spray material of Sample 1 has a small specific surface area of 0.1 m 2 / g, the thermal spray material cannot be sufficiently softened and melted by HOVF thermal spraying, which is a low temperature process. The deposited particles could not be deposited on the substrate.
- the thermal spray material of Sample 1 has an average particle diameter of 24 ⁇ m, which is not extremely large, but the average roundness is as large as 1.8, and the spray material is unevenly conveyed in the powder feeder and the thermal spraying apparatus. Was confirmed to occur.
- thermal spray material of Sample 1 was prepared by the melt-pulverization method and was not subjected to special polishing or the like, so that there were many corners in the ceramic particles, and the fluidity of the thermal spray material was reduced. It is considered a thing.
- a thermal spray coating can be formed by adopting a plasma spray method or the like which is a high temperature process.
- the fluidity of the thermal spray material is not sufficiently obtained, the supply amount of the thermal spray material is not constant, spitting occurs, and the quality of the thermal spray coating is not necessarily sufficient. I could not say.
- the thermal spray material of sample 2 has a specific surface area of 0.4 m 2 / g, which is larger than the thermal spray material of sample 1, it is not sufficient. Therefore, the thermal spray material is softened by HVOF thermal spraying, which is a low temperature process, and the molten particles adhere to the substrate. However, particles that are not sufficiently softened could not contribute to film formation.
- the thermal spray material of Sample 2 has a slightly large average roundness of 1.5, and a sufficient fluidity was not obtained. Therefore, there is a slight unevenness in the conveyance of the thermal spray material in the powder feeder and the thermal spraying apparatus. It was confirmed.
- thermal spray material of sample 2 is prepared by a granulation-sintering method, and the average roundness is suppressed to be lower than that of the thermal spray material of sample 1, but the shape is sufficiently close to a perfect sphere. It was thought that it was because it was not possible. Although the average aspect value of the thermal spray material of Sample 2 was the smallest among all samples, the fluidity of such a thermal spray material can be roughly estimated from the average aspect value, but it has been confirmed that it cannot be fully evaluated up to the detailed range. did it. Although not specifically shown, even with such a thermal spray material, a thermal spray coating can be formed by employing a plasma thermal spraying method or the like. However, even in that case, since the fluidity of the thermal spray material is not sufficiently obtained, the supply amount of the thermal spray material is not constant, spitting occurs, and the quality of the thermal spray coating is not necessarily sufficient. I could not say.
- the thermal spray material of Samples 3 to 8 has a sufficiently large specific surface area of 0.5 m 2 / g or more, as described above, the thermal spray material is also used in HVOF thermal spraying at a temperature lower than the melting point of the thermal spray material. It was confirmed that the film could be sufficiently melted and heated to form a homogeneous film.
- the specific surface area can be suitably used for thermal spraying at a lower temperature by increasing the specific surface area to 0.5 m 2 / g or more. It was confirmed that it was possible.
- the thermal spray materials of Samples 3 to 8 have an average particle diameter of 30 ⁇ m or less, but are sufficiently large as 20 ⁇ m or more, and an average roundness of less than 1.5. It was possible to supply the spray frame at a constant flow rate without clogging in the apparatus.
- the thermal spray material of Samples 3 to 8 can form a thermal spray coating consisting of a fine and dense structure with a particle diameter of less than 5 ⁇ m.
- the thermal spray materials of Samples 3 to 6 are made of alumina.
- the thermal spray temperatures of Samples 3-6 are significantly lower than 1800 ° C. and 1600 ° C., respectively, which is about 2050 ° C., which is the melting point of alumina.
- the thermal spray materials of Samples 7 and 8 are made of yttria and yttria stabilized zirconia.
- the thermal spray temperatures of Samples 7 and 8 are 2300 ° C.
- thermal spray material disclosed here, it is possible to form a thermal spray coating composed of a sufficiently dense and fine structure even by HVOF thermal spraying at a temperature lower than the melting point of the thermal spray material itself. Was confirmed.
- the average particle diameter is less than 6 ⁇ m (for example, 0.01 ⁇ m to 3 ⁇ m) and very fine primary particles are bonded with a gap. It is comprised from the ceramic particle formed by this. Therefore, even if the temperature of the frame does not reach the melting point, it is considered that such a thermal spray material is sufficiently softened and melted to form a thermal spray coating suitably. That is, according to the thermal spray material composed of ceramic particles in the form of secondary particles in which ultrafine particles are bonded with a gap as disclosed herein, a high-quality thermal spray coating is produced even in a low-temperature process below the melting point, for example. It was shown that it can be formed with good properties.
- the primary particles are in the form of nanoparticles or a form close thereto. Therefore, it has been found that the average primary particle diameter of the thermal spray particles constituting the thermal spray coating formed using such a thermal spray material is refined to about 1 ⁇ m or less, and an extremely dense coating structure is formed.
- the thermal spray coating formed from the thermal spray material of Samples 5 to 8 can be extremely dense, for example, the porosity determined by cross-sectional SEM observation is about 1% or less.
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Abstract
Provided is a thermal-spray material capable of forming, with satisfactory productivity, a thermal-spray coating film which is constituted of a ceramic having a dense and fine structure. The thermal-spray material provided by the present invention contains ceramic particles having an average particle diameter of 30 µm or smaller and a specific surface area of 0.5 m2/g or larger. In a preferred embodiment, these ceramic particles are in the form of secondary particles each made up of primary particles three-dimensionally bonded together so as to leave interstices thereamong.
Description
本発明は、溶射材料および溶射皮膜に関する。より詳細には、セラミックス粒子を含む溶射材料およびセラミックス材料からなる溶射皮膜に関する。
本出願は、2013年11月26日に出願された日本国特許出願2013-244276号に基づく優先権を主張しており、その出願の全内容は本明細書中に参照として組み入れられている。 The present invention relates to a thermal spray material and a thermal spray coating. More specifically, the present invention relates to a thermal spray material containing ceramic particles and a thermal spray coating made of the ceramic material.
This application claims priority based on Japanese Patent Application No. 2013-244276 filed on November 26, 2013, the entire contents of which are incorporated herein by reference.
本出願は、2013年11月26日に出願された日本国特許出願2013-244276号に基づく優先権を主張しており、その出願の全内容は本明細書中に参照として組み入れられている。 The present invention relates to a thermal spray material and a thermal spray coating. More specifically, the present invention relates to a thermal spray material containing ceramic particles and a thermal spray coating made of the ceramic material.
This application claims priority based on Japanese Patent Application No. 2013-244276 filed on November 26, 2013, the entire contents of which are incorporated herein by reference.
基材に皮膜を設けることにより新たな機能性を付与する技術は、従来より、様々な分野において利用されている。ドライコーティング技術の一つである溶射法は、金属やセラミックス、サーメット等からなる粒子状の溶射材料を燃焼炎あるいは電気エネルギー等の熱源により溶融させるとともにその溶射粒子を加速させて、基材の表面に吹き付け、堆積させることで、皮膜を形成する手法である。
Technology that imparts new functionality by providing a film on a substrate has been used in various fields. Thermal spraying, which is one of the dry coating technologies, is a method in which a particulate thermal spray material made of metal, ceramics, cermet, etc. is melted by a heat source such as a combustion flame or electric energy, and the thermal spray particles are accelerated to accelerate the surface of the substrate. This is a method of forming a film by spraying and depositing on the film.
なかでも、セラミックス粒子を溶射材料とする溶射技術は、セラミックス材料の特長である耐熱性、耐摩耗性、耐腐食性および耐絶縁性等といった優れた化学的・機械的特性を、比較的経済的にかつ高速で厚膜として基材に付与し得ることから、例えば、金属製部材のコーティングに広く適用されている。セラミックス粒子を溶射材料として溶射を行う従来技術としては、例えば、特許文献1および2が挙げられる。
In particular, thermal spraying technology using ceramic particles as a thermal spray material is relatively economical because of its excellent chemical and mechanical properties such as heat resistance, wear resistance, corrosion resistance, and insulation resistance, which are the characteristics of ceramic materials. In addition, since it can be applied to a substrate as a thick film at a high speed, it is widely applied to coating of metal members, for example. Examples of conventional techniques for performing thermal spraying using ceramic particles as a thermal spray material include Patent Documents 1 and 2.
セラミックス材料は一般に融点が高いことから、通常は、プラズマ溶射法等の高温プロセスにより溶射するのが一般的である。この高温プロセスでの溶射によると、溶射材料としてのセラミックス粒子が溶融状態での飛行中に成長する。そのため、微細な組織を有する溶射皮膜を形成するのは困難であった。
これに対し、セラミックス粒子を含む溶射材料を使用し、高速フレーム溶射法等の低温プロセスにより溶射することが提案されている。しかしながら、セラミックス粒子の溶射に低温プロセスを適用すると、かかるセラミックス粒子が十分に溶融せず、溶射皮膜の成膜速度や溶射付着率が低くなってしまうという問題がある。 Since ceramic materials generally have a high melting point, they are usually sprayed by a high temperature process such as plasma spraying. According to the thermal spraying in this high temperature process, ceramic particles as the thermal spray material grow during flight in the molten state. Therefore, it has been difficult to form a sprayed coating having a fine structure.
On the other hand, it has been proposed to use a thermal spray material containing ceramic particles and perform thermal spraying by a low temperature process such as a high-speed flame spraying method. However, when a low temperature process is applied to the thermal spraying of ceramic particles, there is a problem that the ceramic particles are not sufficiently melted, and the deposition rate of the thermal spray coating and the thermal spray adhesion rate are lowered.
これに対し、セラミックス粒子を含む溶射材料を使用し、高速フレーム溶射法等の低温プロセスにより溶射することが提案されている。しかしながら、セラミックス粒子の溶射に低温プロセスを適用すると、かかるセラミックス粒子が十分に溶融せず、溶射皮膜の成膜速度や溶射付着率が低くなってしまうという問題がある。 Since ceramic materials generally have a high melting point, they are usually sprayed by a high temperature process such as plasma spraying. According to the thermal spraying in this high temperature process, ceramic particles as the thermal spray material grow during flight in the molten state. Therefore, it has been difficult to form a sprayed coating having a fine structure.
On the other hand, it has been proposed to use a thermal spray material containing ceramic particles and perform thermal spraying by a low temperature process such as a high-speed flame spraying method. However, when a low temperature process is applied to the thermal spraying of ceramic particles, there is a problem that the ceramic particles are not sufficiently melted, and the deposition rate of the thermal spray coating and the thermal spray adhesion rate are lowered.
そこで、低温プロセスにおいてセラミックス粒子を十分に加熱させるべく、その粒子径を微細にすることが検討されてもいる。しかしながら、セラミックス粒子の粒子径が微細になればなるほど、高速の溶射フレームに溶射材料が弾かれ易くなるため、溶射材料を溶射フレームに供給すること自体が困難であった。なお、溶射材料をナノメートルサイズにまで微細化する場合、スラリーの形態で溶射に供することが提案されてもいる(例えば、特許文献2参照)。しかしながら、乾燥状態にある溶射材料が経時変化しにくいのに対し、スラリーの形態の溶射材料は沈降を生じる等して経時変化しやすく、扱い難いという新たな問題が生じてしまっていた。さらには、スラリーの調製後から溶射に供されるまでの短時間でもスラリーの状態(例えば、分散状態)が変化しやすく、形成される溶射皮膜の品質に影響が及ぶという問題もあった。加えて、溶射付着率や成膜速度が低くなってしまうという問題は解消されていない。
Therefore, in order to sufficiently heat the ceramic particles in a low temperature process, it has been studied to make the particle diameter fine. However, as the particle diameter of the ceramic particles becomes finer, it becomes easier for the spray material to be repelled by the high-speed spray frame, and thus it is difficult to supply the spray material to the spray frame itself. In addition, when miniaturizing a thermal spray material to nanometer size, providing to a thermal spray with the form of a slurry is also proposed (for example, refer patent document 2). However, while the sprayed material in a dry state is less likely to change with time, the sprayed material in the form of a slurry is liable to change with time due to sedimentation or the like, resulting in a new problem that it is difficult to handle. Furthermore, there is also a problem that the state of the slurry (for example, the dispersed state) is likely to change even in a short time from the preparation of the slurry to being subjected to thermal spraying, which affects the quality of the thermal spray coating to be formed. In addition, the problem that the thermal spray adhesion rate and the film formation rate are low has not been solved.
本発明はかかる点に鑑みてなされたものであり、緻密で微細な組織を有するセラミックスからなる溶射皮膜を生産性良く形成することができる溶射材料を提供することを目的としている。また、本発明の他の目的は、緻密で微細な組織を有するセラミックスからなる溶射皮膜を提供することである。
The present invention has been made in view of such a point, and an object of the present invention is to provide a thermal spray material capable of forming a thermal spray coating composed of a ceramic having a dense and fine structure with high productivity. Another object of the present invention is to provide a thermal spray coating made of a ceramic having a dense and fine structure.
上記目的を実現するべく、本発明により、溶射材料を提供する。かかる溶射材料は、平均粒子径が30μm以下であって、比表面積が0.5m2/g以上のセラミックス粒子を含むことを特徴としている。
ここに開示される溶射材料において、セラミックス粒子の平均粒子径自体は、上記のとおり溶射材料の供給に適した大きさであり得る。そして、粒成長が抑制され得る溶射温度において、溶射材料が軟化または溶融するに十分な熱が供給され得るように比表面積が増大されている。また、かかる比表面積の増大に伴い、溶射材料は表面が3次元的に入り組んだ複雑な形状(構造)を有することになり、実質的な寸法(例えば、表面の凹凸部における厚み)が低減される。かかる構成により、セラミックス溶融粒子は成長が抑制され、十分に溶融された状態で基材に到達し得る。これにより、緻密で微細な組織を有するセラミックスからなる溶射皮膜を、生産性良く形成することができる溶射材料が実現される。 In order to achieve the above object, the present invention provides a thermal spray material. Such a thermal spray material is characterized by containing ceramic particles having an average particle diameter of 30 μm or less and a specific surface area of 0.5 m 2 / g or more.
In the thermal spray material disclosed here, the average particle diameter of the ceramic particles can be a size suitable for supplying the thermal spray material as described above. The specific surface area is increased so that heat sufficient to soften or melt the sprayed material can be supplied at a spraying temperature at which grain growth can be suppressed. As the specific surface area increases, the thermal spray material has a complicated shape (structure) in which the surface is three-dimensionally complicated, and the substantial dimension (for example, the thickness of the uneven portion of the surface) is reduced. The With this configuration, the ceramic melt particles are prevented from growing and can reach the substrate in a sufficiently melted state. Thereby, the thermal spray material which can form the thermal spray coating which consists of ceramics which have a precise | minute and fine structure | tissue with sufficient productivity is implement | achieved.
ここに開示される溶射材料において、セラミックス粒子の平均粒子径自体は、上記のとおり溶射材料の供給に適した大きさであり得る。そして、粒成長が抑制され得る溶射温度において、溶射材料が軟化または溶融するに十分な熱が供給され得るように比表面積が増大されている。また、かかる比表面積の増大に伴い、溶射材料は表面が3次元的に入り組んだ複雑な形状(構造)を有することになり、実質的な寸法(例えば、表面の凹凸部における厚み)が低減される。かかる構成により、セラミックス溶融粒子は成長が抑制され、十分に溶融された状態で基材に到達し得る。これにより、緻密で微細な組織を有するセラミックスからなる溶射皮膜を、生産性良く形成することができる溶射材料が実現される。 In order to achieve the above object, the present invention provides a thermal spray material. Such a thermal spray material is characterized by containing ceramic particles having an average particle diameter of 30 μm or less and a specific surface area of 0.5 m 2 / g or more.
In the thermal spray material disclosed here, the average particle diameter of the ceramic particles can be a size suitable for supplying the thermal spray material as described above. The specific surface area is increased so that heat sufficient to soften or melt the sprayed material can be supplied at a spraying temperature at which grain growth can be suppressed. As the specific surface area increases, the thermal spray material has a complicated shape (structure) in which the surface is three-dimensionally complicated, and the substantial dimension (for example, the thickness of the uneven portion of the surface) is reduced. The With this configuration, the ceramic melt particles are prevented from growing and can reach the substrate in a sufficiently melted state. Thereby, the thermal spray material which can form the thermal spray coating which consists of ceramics which have a precise | minute and fine structure | tissue with sufficient productivity is implement | achieved.
なお、本明細書において、セラミックス粒子に係る「平均粒子径」とは、特筆しない限り、レーザ散乱・回折法に基づく粒度分布測定装置により測定された粒度分布における積算値50%での粒子径(50%体積平均粒子径;D50)を意味する。
また、本明細書において、「比表面積」は、BET法に基づき、溶射材料の表面に物理吸着したガス(典型的には窒素(N2)ガス)の量を測定することによって決定される、当該溶射材料を構成する一次粒子の外部および内部の全ての表面積をその質量で除した値を意味している。かかる比表面積は、JIS Z 8830:2013(ISO9277:2010)「ガス吸着による粉体(固体)の比表面積測定方法」の規定に準じて測定することができる。 In the present specification, the “average particle diameter” relating to ceramic particles means, unless otherwise specified, a particle diameter at an integrated value of 50% in a particle size distribution measured by a particle size distribution measuring apparatus based on a laser scattering / diffraction method ( Means 50% volume average particle size; D50).
In the present specification, the “specific surface area” is determined by measuring the amount of gas (typically nitrogen (N 2 ) gas) physically adsorbed on the surface of the thermal spray material based on the BET method. It means a value obtained by dividing all the external and internal surface areas of the primary particles constituting the thermal spray material by their masses. Such a specific surface area can be measured in accordance with JIS Z 8830: 2013 (ISO 9277: 2010) “Method for measuring specific surface area of powder (solid) by gas adsorption”.
また、本明細書において、「比表面積」は、BET法に基づき、溶射材料の表面に物理吸着したガス(典型的には窒素(N2)ガス)の量を測定することによって決定される、当該溶射材料を構成する一次粒子の外部および内部の全ての表面積をその質量で除した値を意味している。かかる比表面積は、JIS Z 8830:2013(ISO9277:2010)「ガス吸着による粉体(固体)の比表面積測定方法」の規定に準じて測定することができる。 In the present specification, the “average particle diameter” relating to ceramic particles means, unless otherwise specified, a particle diameter at an integrated value of 50% in a particle size distribution measured by a particle size distribution measuring apparatus based on a laser scattering / diffraction method ( Means 50% volume average particle size; D50).
In the present specification, the “specific surface area” is determined by measuring the amount of gas (typically nitrogen (N 2 ) gas) physically adsorbed on the surface of the thermal spray material based on the BET method. It means a value obtained by dividing all the external and internal surface areas of the primary particles constituting the thermal spray material by their masses. Such a specific surface area can be measured in accordance with JIS Z 8830: 2013 (ISO 9277: 2010) “Method for measuring specific surface area of powder (solid) by gas adsorption”.
ここに開示される溶射材料の好ましい一形態において、前記セラミックス粒子は、一次粒子が間隙をもって3次元的に結合されてなる二次粒子の形態を有していることを特徴としている。かかる一次粒子は、平均粒子径が6μm未満であるのがより望ましい形態であり得る。
すなわち、ここに開示される溶射材料を構成するセラミックス粒子は、例えば多孔質な単一の粒子から構成される形態であっても良い。しかしながら、例えば、高速フレーム溶射法等の低温プロセスに供することを考慮すると、上記の通り、微細な一次粒子が結合された二次粒子の形態であるのが好ましい。かかる構成によると、より低い温度の溶射フレーム等に溶射材料を供給した場合であっても、溶射材料に含まれるセラミックス粒子を適切に軟化溶融させることができ、緻密な溶射皮膜を好適に得ることができる。また、低温プロセスにおいては溶融された溶融粒子の成長が抑制されるため、一次粒子の寸法に由来したより微細な組織を有する溶射皮膜を得ることができる。これにより、セラミックスからなる溶射皮膜を、より一層緻密で微細な組織を有するものとして高品質に形成することができる溶射材料が実現される。延いては、所望の特性を備える溶射皮膜を得るための設計をより簡便に行うことができる溶射材料が提供される。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized by having a form of secondary particles in which primary particles are three-dimensionally bonded with a gap. Such primary particles may be in a more desirable form with an average particle size of less than 6 μm.
That is, the ceramic particle which comprises the thermal spray material disclosed here may be a form comprised from a single porous particle, for example. However, considering the use in a low-temperature process such as a high-speed flame spraying method, for example, as described above, the form of secondary particles in which fine primary particles are combined is preferable. According to such a configuration, even when the thermal spray material is supplied to a lower temperature thermal spray frame or the like, the ceramic particles contained in the thermal spray material can be appropriately softened and melted, and a dense thermal spray coating is suitably obtained. Can do. In addition, since the growth of melted molten particles is suppressed in the low temperature process, a sprayed coating having a finer structure derived from the size of the primary particles can be obtained. Thereby, the thermal spray material which can form the thermal spray coating consisting of ceramics as a thing which has a denser and fine structure with high quality is realized. As a result, a thermal spray material that can be more easily designed to obtain a thermal spray coating having desired characteristics is provided.
すなわち、ここに開示される溶射材料を構成するセラミックス粒子は、例えば多孔質な単一の粒子から構成される形態であっても良い。しかしながら、例えば、高速フレーム溶射法等の低温プロセスに供することを考慮すると、上記の通り、微細な一次粒子が結合された二次粒子の形態であるのが好ましい。かかる構成によると、より低い温度の溶射フレーム等に溶射材料を供給した場合であっても、溶射材料に含まれるセラミックス粒子を適切に軟化溶融させることができ、緻密な溶射皮膜を好適に得ることができる。また、低温プロセスにおいては溶融された溶融粒子の成長が抑制されるため、一次粒子の寸法に由来したより微細な組織を有する溶射皮膜を得ることができる。これにより、セラミックスからなる溶射皮膜を、より一層緻密で微細な組織を有するものとして高品質に形成することができる溶射材料が実現される。延いては、所望の特性を備える溶射皮膜を得るための設計をより簡便に行うことができる溶射材料が提供される。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized by having a form of secondary particles in which primary particles are three-dimensionally bonded with a gap. Such primary particles may be in a more desirable form with an average particle size of less than 6 μm.
That is, the ceramic particle which comprises the thermal spray material disclosed here may be a form comprised from a single porous particle, for example. However, considering the use in a low-temperature process such as a high-speed flame spraying method, for example, as described above, the form of secondary particles in which fine primary particles are combined is preferable. According to such a configuration, even when the thermal spray material is supplied to a lower temperature thermal spray frame or the like, the ceramic particles contained in the thermal spray material can be appropriately softened and melted, and a dense thermal spray coating is suitably obtained. Can do. In addition, since the growth of melted molten particles is suppressed in the low temperature process, a sprayed coating having a finer structure derived from the size of the primary particles can be obtained. Thereby, the thermal spray material which can form the thermal spray coating consisting of ceramics as a thing which has a denser and fine structure with high quality is realized. As a result, a thermal spray material that can be more easily designed to obtain a thermal spray coating having desired characteristics is provided.
なお、本明細書において、一次粒子に関する「平均粒子径」は、上記の比表面積を実現し得る球形粒子の直径(球相当径)として算出される値である。かかる一次粒子の平均粒子径(Dave)は、上記セラミックス粒子(二次粒子)の比表面積をSm、密度をρとしたとき、次式に基づき求めることができる。なお、セラミックス粒子が複数のセラミックス材料の混合物である場合、密度は、それら複数のセラミックス材料の密度を配合割合に応じて足し合わせた値(加重平均値)を採用することができる。
Dave=6/(ρSm)
また、ここでいう「間隙」とは、例えば、当該一次粒子が最密充填された場合に必然的に形成される空間よりも、より広い空間を意味している。典型的には、かかる「間隙」は、当該一次粒子が最密充填された場合に必然的に形成される空間の、1.2倍以上の空間であり得る。 In the present specification, the “average particle diameter” relating to the primary particles is a value calculated as the diameter (spherical equivalent diameter) of the spherical particles capable of realizing the above specific surface area. The average particle diameter (D ave ) of the primary particles can be obtained based on the following formula, where S m is the specific surface area of the ceramic particles (secondary particles) and ρ is the density. When the ceramic particles are a mixture of a plurality of ceramic materials, a value (weighted average value) obtained by adding the densities of the plurality of ceramic materials according to the blending ratio can be employed.
D ave = 6 / (ρS m )
In addition, the “gap” here means a larger space than a space inevitably formed when the primary particles are packed most closely. Typically, such a “gap” may be a space that is 1.2 times or more the space that is inevitably formed when the primary particles are closest packed.
Dave=6/(ρSm)
また、ここでいう「間隙」とは、例えば、当該一次粒子が最密充填された場合に必然的に形成される空間よりも、より広い空間を意味している。典型的には、かかる「間隙」は、当該一次粒子が最密充填された場合に必然的に形成される空間の、1.2倍以上の空間であり得る。 In the present specification, the “average particle diameter” relating to the primary particles is a value calculated as the diameter (spherical equivalent diameter) of the spherical particles capable of realizing the above specific surface area. The average particle diameter (D ave ) of the primary particles can be obtained based on the following formula, where S m is the specific surface area of the ceramic particles (secondary particles) and ρ is the density. When the ceramic particles are a mixture of a plurality of ceramic materials, a value (weighted average value) obtained by adding the densities of the plurality of ceramic materials according to the blending ratio can be employed.
D ave = 6 / (ρS m )
In addition, the “gap” here means a larger space than a space inevitably formed when the primary particles are packed most closely. Typically, such a “gap” may be a space that is 1.2 times or more the space that is inevitably formed when the primary particles are closest packed.
ここに開示される溶射材料の好ましい一形態において、前記セラミックス粒子は、平面視における平均真円度が1.5未満であることを特徴としている。
従来の溶射材料において、球形化処理が施されていないセラミックス粒子は、結晶性が高いことから結晶系の外形がそのまま粒子の形態となって表れやすい傾向があった。とりわけ、球形化処理を施しにくいナノメートルサイズのセラミックス粒子や、結晶面に沿って破砕されたセラミックス粒子は、その傾向が強い。したがって、結晶系に由来する稜や隅角(頂点であり得る)や角部を有するセラミックス粒子を含む溶射材料は、供給装置や溶射ガンからフレームに供給されるまでの間に、供給装置や溶射ガンの表面に稜や隅角、角部等が引っかかったり、セラミックス粒子同士が互いにかみ合ったりして、流動性が低下しがちであった。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles have an average roundness in a plan view of less than 1.5.
In conventional thermal spray materials, ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are. In particular, nanometer-sized ceramic particles that are difficult to spheroidize and ceramic particles crushed along the crystal plane have a strong tendency. Therefore, the thermal spray material containing ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame. Ridges, corners, corners, and the like are caught on the surface of the gun, and ceramic particles tend to mesh with each other, which tends to reduce fluidity.
従来の溶射材料において、球形化処理が施されていないセラミックス粒子は、結晶性が高いことから結晶系の外形がそのまま粒子の形態となって表れやすい傾向があった。とりわけ、球形化処理を施しにくいナノメートルサイズのセラミックス粒子や、結晶面に沿って破砕されたセラミックス粒子は、その傾向が強い。したがって、結晶系に由来する稜や隅角(頂点であり得る)や角部を有するセラミックス粒子を含む溶射材料は、供給装置や溶射ガンからフレームに供給されるまでの間に、供給装置や溶射ガンの表面に稜や隅角、角部等が引っかかったり、セラミックス粒子同士が互いにかみ合ったりして、流動性が低下しがちであった。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles have an average roundness in a plan view of less than 1.5.
In conventional thermal spray materials, ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are. In particular, nanometer-sized ceramic particles that are difficult to spheroidize and ceramic particles crushed along the crystal plane have a strong tendency. Therefore, the thermal spray material containing ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame. Ridges, corners, corners, and the like are caught on the surface of the gun, and ceramic particles tend to mesh with each other, which tends to reduce fluidity.
ここに開示される溶射材料においては、セラミックス粒子の平均真円度が上記の通り小さく制限され、真円に近い外形を有している。したがって、かかる溶射材料を流動させるに際し、セラミックス粒子(例えば、上記の一次粒子であり得る。)の稜や隅角、角部等の外形によって流動性が低下されるのが抑制される。その結果、溶射装置への溶射材料の供給が容易で安定になされ、溶射フレームやガス等の中心部への溶射材料の供給を好適に行うことができ、溶射効率の向上および溶射皮膜の品質の向上を図ることができる。
In the thermal spray material disclosed here, the average roundness of the ceramic particles is limited to be small as described above, and has an outer shape close to a perfect circle. Therefore, when this thermal spray material is made to flow, it is suppressed that fluidity | liquidity falls by external shapes, such as the edge of a ceramic particle (for example, it may be said primary particle), a corner, and a corner | angular part. As a result, it is easy and stable to supply the thermal spray material to the thermal spraying device, and it is possible to suitably supply the thermal spray material to the center of the thermal spray frame and gas, improving the thermal spray efficiency and improving the quality of the thermal spray coating. Improvements can be made.
なお、本明細書における、セラミックス粒子の「平均真円度」とは、電子顕微鏡等の観察手段により観察された100以上のセラミックス粒子の平面視像(例えば、二次電子像等)について求められた真円度の算術平均値を意味する。また、真円度は、セラミックス粒子の平面視像において、当該セラミックス粒子の輪郭の長さである周囲長と、かかる輪郭で囲まれた面積とから、下記式により規定される値である。なお、かかる真円度は、セラミックス粒子の表面形態の滑らかさをより反映しやすい指標であり、幾何学的円(真円)は真円度=1となり、真円から離れるにつれて真円度は1より大きな値となる。かかる平均真円度は、例えば、適切な倍率で取得した電子顕微鏡像を、画像処理ソフト等を用いて解析することで求めることができる。
真円度=(周囲長2)÷(4×π×面積) In the present specification, the “average roundness” of the ceramic particles is obtained for a planar view image (for example, a secondary electron image) of 100 or more ceramic particles observed by an observation means such as an electron microscope. It means the arithmetic average value of roundness. Further, the roundness is a value defined by the following expression from the peripheral length that is the length of the outline of the ceramic particle and the area surrounded by the outline in the plan view image of the ceramic particle. The roundness is an index that more easily reflects the smoothness of the surface morphology of the ceramic particles. The geometrical circle (roundness) is roundness = 1, and the roundness is increased as the distance from the roundness increases. A value greater than 1. Such average roundness can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
Roundness = (perimeter 2 ) ÷ (4 x π x area)
真円度=(周囲長2)÷(4×π×面積) In the present specification, the “average roundness” of the ceramic particles is obtained for a planar view image (for example, a secondary electron image) of 100 or more ceramic particles observed by an observation means such as an electron microscope. It means the arithmetic average value of roundness. Further, the roundness is a value defined by the following expression from the peripheral length that is the length of the outline of the ceramic particle and the area surrounded by the outline in the plan view image of the ceramic particle. The roundness is an index that more easily reflects the smoothness of the surface morphology of the ceramic particles. The geometrical circle (roundness) is roundness = 1, and the roundness is increased as the distance from the roundness increases. A value greater than 1. Such average roundness can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
Roundness = (perimeter 2 ) ÷ (4 x π x area)
ここに開示される溶射材料の好ましい一態様において、上記セラミックス粒子は、平面視における平均アスペクト比が1.4未満であることを特徴としている。
上述の真円度は、セラミックス粒子の円形度(球形度であり得る。)のうちでも表面形態をより反映しやすい指標であり、セラミックス粒子の平面視における輪郭線が複雑になればなるほどその値は大きくなる傾向にある。すなわち、上記のとおり平均真円度がより1に近いセラミックス粒子において、真円度は、セラミックス粒子の全体的な形態よりも表面形態をより反映するものであり得る。そこで、ここに開示される技術においては、かかる真円度とは別に、アスペクト比によっても、セラミックス粒子の形態を評価するようにしている。かかる構成によると、セラミックス粒子の形態が全体としてより一層真球(すなわち、平面視において真円)に近いセラミックス粒子を含む溶射材料を実現することができる。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized in that an average aspect ratio in a plan view is less than 1.4.
The roundness described above is an index that more easily reflects the surface form among the circularity (can be spherical) of the ceramic particles, and the value becomes more complicated as the contour line in the plan view of the ceramic particles becomes more complicated. Tend to grow. That is, in the ceramic particles having an average roundness closer to 1 as described above, the roundness may more reflect the surface form than the overall form of the ceramic particles. Therefore, in the technology disclosed herein, the form of the ceramic particles is evaluated not only by the roundness but also by the aspect ratio. According to this configuration, it is possible to realize a thermal spray material including ceramic particles whose shape of ceramic particles is closer to a perfect sphere (that is, a perfect circle in plan view) as a whole.
上述の真円度は、セラミックス粒子の円形度(球形度であり得る。)のうちでも表面形態をより反映しやすい指標であり、セラミックス粒子の平面視における輪郭線が複雑になればなるほどその値は大きくなる傾向にある。すなわち、上記のとおり平均真円度がより1に近いセラミックス粒子において、真円度は、セラミックス粒子の全体的な形態よりも表面形態をより反映するものであり得る。そこで、ここに開示される技術においては、かかる真円度とは別に、アスペクト比によっても、セラミックス粒子の形態を評価するようにしている。かかる構成によると、セラミックス粒子の形態が全体としてより一層真球(すなわち、平面視において真円)に近いセラミックス粒子を含む溶射材料を実現することができる。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized in that an average aspect ratio in a plan view is less than 1.4.
The roundness described above is an index that more easily reflects the surface form among the circularity (can be spherical) of the ceramic particles, and the value becomes more complicated as the contour line in the plan view of the ceramic particles becomes more complicated. Tend to grow. That is, in the ceramic particles having an average roundness closer to 1 as described above, the roundness may more reflect the surface form than the overall form of the ceramic particles. Therefore, in the technology disclosed herein, the form of the ceramic particles is evaluated not only by the roundness but also by the aspect ratio. According to this configuration, it is possible to realize a thermal spray material including ceramic particles whose shape of ceramic particles is closer to a perfect sphere (that is, a perfect circle in plan view) as a whole.
なお、本明細書においては、「平均アスペクト比」とは、電子顕微鏡等の観察手段により観察された100以上のセラミックス粒子の平面視像(二次電子像等)について求められたアスペクト比の算術平均値を意味する。かかるアスペクト比は、当該セラミックス粒子の相当楕円における長軸の長さをa、短軸の長さをbとしたとき、a/bで定義される。また、相当楕円とは、当該セラミックス粒子と同面積で、かつ一次および二次モーメントが等しい楕円をいう。かかる平均アスペクト比は、例えば、適切な倍率で取得した電子顕微鏡像を画像処理ソフト等を用いて解析することで求めることができる。
In the present specification, the “average aspect ratio” means the arithmetic operation of the aspect ratio obtained for a planar view image (secondary electron image, etc.) of 100 or more ceramic particles observed by an observation means such as an electron microscope. Mean value. The aspect ratio is defined as a / b, where a is the major axis length and b is the minor axis length of the corresponding ellipse of the ceramic particle. The equivalent ellipse is an ellipse having the same area as the ceramic particles and equal primary and secondary moments. Such an average aspect ratio can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
ここに開示される溶射材料の好ましい一態様において、上記セラミックス粒子は、平均フラクタル次元が1.07未満であることを特徴としている。
フラクタル次元(Fractal Dimension:FD)は、粒子表面の複雑な形態を測るために利用される指標であり得る。ここに開示される技術においては、セラミックス粒子が上記の平均フラクタル次元を有しているため、より滑らかな表面を有し、溶射材料の流動性が向上されたものとして実現されている。その結果、溶射装置への溶射用粉末の供給がより一層安定し、フレームまたは作動ガス中心部等への溶射材料の投入が容易となり得る。延いては、溶射材料が、溶射プロセスによる加熱や加速の効果を好適に受けることができ、溶射効率が向上されるとともに、形成される皮膜の品質の向上を図ることができる。
なお、本明細書においては、「平均フラクタル次元」とは、電子顕微鏡等の観察手段により観察された100以上のセラミックス粒子の平面視像(二次電子像等)について求められたフラクタル次元の算術平均値を意味する。また、本明細書において、フラクタル次元は、ディバイダーズメソッドにより求められる値を採用しており、セラミックス粒子の平面視像における当該セラミックス粒子の周囲長とストライド長の対数を関連づける関数の、線形部分の傾きとして定義される。かかるフラクタル次元の測定値は、1(=実線)以上2(=平面)未満の値となり、1に近い程セラミックス粒子の表面が滑らかなことを意味する。かかる平均フラクタル次元は、例えば、適切な倍率で取得した電子顕微鏡像を画像処理ソフト等を用いて解析することで求めることができる。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized by having an average fractal dimension of less than 1.07.
Fractal dimension (FD) can be an index used to measure the complex morphology of the particle surface. In the technique disclosed here, since the ceramic particles have the above average fractal dimension, it is realized as having a smoother surface and improved fluidity of the thermal spray material. As a result, the supply of the thermal spraying powder to the thermal spraying apparatus can be further stabilized, and the spraying material can be easily put into the frame or the working gas central part. As a result, the thermal spraying material can suitably receive the effects of heating and acceleration by the thermal spraying process, improving the thermal spraying efficiency and improving the quality of the coating film to be formed.
In the present specification, “average fractal dimension” means an arithmetic of a fractal dimension obtained for a planar view image (secondary electron image or the like) of 100 or more ceramic particles observed by an observation means such as an electron microscope. Mean value. Further, in this specification, the fractal dimension employs a value obtained by the divider method, and the linear part of the function relating the logarithm of the perimeter of the ceramic particle and the stride length in the planar view of the ceramic particle. Defined as slope. The measured value of the fractal dimension is 1 (= solid line) or more and less than 2 (= plane), and the closer to 1, the smoother the surface of the ceramic particles. Such an average fractal dimension can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
フラクタル次元(Fractal Dimension:FD)は、粒子表面の複雑な形態を測るために利用される指標であり得る。ここに開示される技術においては、セラミックス粒子が上記の平均フラクタル次元を有しているため、より滑らかな表面を有し、溶射材料の流動性が向上されたものとして実現されている。その結果、溶射装置への溶射用粉末の供給がより一層安定し、フレームまたは作動ガス中心部等への溶射材料の投入が容易となり得る。延いては、溶射材料が、溶射プロセスによる加熱や加速の効果を好適に受けることができ、溶射効率が向上されるとともに、形成される皮膜の品質の向上を図ることができる。
なお、本明細書においては、「平均フラクタル次元」とは、電子顕微鏡等の観察手段により観察された100以上のセラミックス粒子の平面視像(二次電子像等)について求められたフラクタル次元の算術平均値を意味する。また、本明細書において、フラクタル次元は、ディバイダーズメソッドにより求められる値を採用しており、セラミックス粒子の平面視像における当該セラミックス粒子の周囲長とストライド長の対数を関連づける関数の、線形部分の傾きとして定義される。かかるフラクタル次元の測定値は、1(=実線)以上2(=平面)未満の値となり、1に近い程セラミックス粒子の表面が滑らかなことを意味する。かかる平均フラクタル次元は、例えば、適切な倍率で取得した電子顕微鏡像を画像処理ソフト等を用いて解析することで求めることができる。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are characterized by having an average fractal dimension of less than 1.07.
Fractal dimension (FD) can be an index used to measure the complex morphology of the particle surface. In the technique disclosed here, since the ceramic particles have the above average fractal dimension, it is realized as having a smoother surface and improved fluidity of the thermal spray material. As a result, the supply of the thermal spraying powder to the thermal spraying apparatus can be further stabilized, and the spraying material can be easily put into the frame or the working gas central part. As a result, the thermal spraying material can suitably receive the effects of heating and acceleration by the thermal spraying process, improving the thermal spraying efficiency and improving the quality of the coating film to be formed.
In the present specification, “average fractal dimension” means an arithmetic of a fractal dimension obtained for a planar view image (secondary electron image or the like) of 100 or more ceramic particles observed by an observation means such as an electron microscope. Mean value. Further, in this specification, the fractal dimension employs a value obtained by the divider method, and the linear part of the function relating the logarithm of the perimeter of the ceramic particle and the stride length in the planar view of the ceramic particle. Defined as slope. The measured value of the fractal dimension is 1 (= solid line) or more and less than 2 (= plane), and the closer to 1, the smoother the surface of the ceramic particles. Such an average fractal dimension can be obtained, for example, by analyzing an electron microscope image acquired at an appropriate magnification using image processing software or the like.
ここに開示される溶射材料の好ましい一態様においては、安息角が35°未満であることを特徴としている。
安息角は、粉体の流動性を示し得る指標であり、粉体の粒度(平均粒子径)等にもよるため一概には言えないものの、一般的に、流動性の良い粉体ほど安息角が小さく、流動性の良くない粉体の場合には安息角が大きくなり得る。かかる構成によると、例えば、平均粒子径が30μm未満の溶射材料について流動性が高いと判断することができ、溶射皮膜をより一層生産性良く形成することができる溶射材料を提供することができる。
なお、本明細書において、「安息角」は、溶射材料を一定の高さの漏斗から水平な基板の上に落下させることで生成した円すい状の堆積物の直径および高さから算出される底角を意味している。かかる安息角は、JIS R 9301-2-2:1999「アルミナ粉末物性測定方法-2:安息角」の規定に準じて測定することができる。 In a preferred embodiment of the thermal spray material disclosed herein, the angle of repose is less than 35 °.
The angle of repose is an index that can indicate the fluidity of the powder, and since it depends on the particle size (average particle diameter) of the powder, etc. The angle of repose can be increased in the case of a powder having a small particle size and poor fluidity. According to such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 μm has high fluidity, and it is possible to provide a thermal spraying material capable of forming a thermal spray coating with higher productivity.
In the present specification, the “repose angle” is a bottom calculated from the diameter and height of the conical deposit generated by dropping the sprayed material from a funnel having a certain height onto a horizontal substrate. Means a corner. Such angle of repose can be measured in accordance with the provisions of JIS R 9301-2-2: 1999 “Alumina powder physical property measurement method-2: angle of repose”.
安息角は、粉体の流動性を示し得る指標であり、粉体の粒度(平均粒子径)等にもよるため一概には言えないものの、一般的に、流動性の良い粉体ほど安息角が小さく、流動性の良くない粉体の場合には安息角が大きくなり得る。かかる構成によると、例えば、平均粒子径が30μm未満の溶射材料について流動性が高いと判断することができ、溶射皮膜をより一層生産性良く形成することができる溶射材料を提供することができる。
なお、本明細書において、「安息角」は、溶射材料を一定の高さの漏斗から水平な基板の上に落下させることで生成した円すい状の堆積物の直径および高さから算出される底角を意味している。かかる安息角は、JIS R 9301-2-2:1999「アルミナ粉末物性測定方法-2:安息角」の規定に準じて測定することができる。 In a preferred embodiment of the thermal spray material disclosed herein, the angle of repose is less than 35 °.
The angle of repose is an index that can indicate the fluidity of the powder, and since it depends on the particle size (average particle diameter) of the powder, etc. The angle of repose can be increased in the case of a powder having a small particle size and poor fluidity. According to such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 μm has high fluidity, and it is possible to provide a thermal spraying material capable of forming a thermal spray coating with higher productivity.
In the present specification, the “repose angle” is a bottom calculated from the diameter and height of the conical deposit generated by dropping the sprayed material from a funnel having a certain height onto a horizontal substrate. Means a corner. Such angle of repose can be measured in accordance with the provisions of JIS R 9301-2-2: 1999 “Alumina powder physical property measurement method-2: angle of repose”.
ここに開示される溶射材料の好ましい一態様において、上記セラミックス粒子は、アルミナ、ジルコニア、イットリア、シリカ、炭化ケイ素、炭化ホウ素、窒化ケイ素、サイアロン、窒化アルミニウムおよびハイドロキシアパタイトからなる群から選択される1種または2種以上のセラミックス材料を含むことを特徴としている。
かかる構成によると、例えば、上記のセラミックス材料の単独の機能、あるいは2種状のセラミックス材料を混合ないしは複合化した材料の機能に対応する機能を備える溶射皮膜を形成することができる溶射材料が提供される。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are selected from the group consisting of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite. It is characterized by containing a seed or two or more ceramic materials.
According to this configuration, for example, there is provided a thermal spray material capable of forming a thermal spray coating having a function corresponding to the function of a single material of the above ceramic material or the function of a material obtained by mixing or combining two types of ceramic materials. Is done.
かかる構成によると、例えば、上記のセラミックス材料の単独の機能、あるいは2種状のセラミックス材料を混合ないしは複合化した材料の機能に対応する機能を備える溶射皮膜を形成することができる溶射材料が提供される。 In a preferred embodiment of the thermal spray material disclosed herein, the ceramic particles are selected from the group consisting of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite. It is characterized by containing a seed or two or more ceramic materials.
According to this configuration, for example, there is provided a thermal spray material capable of forming a thermal spray coating having a function corresponding to the function of a single material of the above ceramic material or the function of a material obtained by mixing or combining two types of ceramic materials. Is done.
他の側面において、ここに開示される発明は、セラミックス材料からなる溶射粒子が基材上に堆積されてなる溶射皮膜を提供する。かかる溶射皮膜は、上記基材の表面に垂直な断面における前記溶射粒子の平均粒子径が5μm未満であることを特徴としている。
かかる構成によると、セラミックス材料からなる溶射皮膜であっても、粒子径が上記のとおり微細で緻密な溶射皮膜が実現され得る。 In another aspect, the invention disclosed herein provides a thermal spray coating in which thermal spray particles made of a ceramic material are deposited on a substrate. The thermal spray coating is characterized in that the average particle diameter of the thermal spray particles in a cross section perpendicular to the surface of the substrate is less than 5 μm.
According to such a configuration, even if the sprayed coating is made of a ceramic material, a fine and dense sprayed coating having a particle diameter as described above can be realized.
かかる構成によると、セラミックス材料からなる溶射皮膜であっても、粒子径が上記のとおり微細で緻密な溶射皮膜が実現され得る。 In another aspect, the invention disclosed herein provides a thermal spray coating in which thermal spray particles made of a ceramic material are deposited on a substrate. The thermal spray coating is characterized in that the average particle diameter of the thermal spray particles in a cross section perpendicular to the surface of the substrate is less than 5 μm.
According to such a configuration, even if the sprayed coating is made of a ceramic material, a fine and dense sprayed coating having a particle diameter as described above can be realized.
なお、本明細書において、溶射粒子に関する「平均粒子径」は、当該溶射皮膜の基材に略垂直な断面における組織の観察像を画像解析することで求められる値である。具体的には、溶射皮膜の基材に略垂直な断面組織を所定の倍率の顕微鏡等で観察することで得られた観察像について、気孔部と固相部とを分離する2値化を行い、これを画像解析ソフトを用いて解析することで、100個以上の溶射粒子についての円相当径の算術平均値として得られる値である。
In the present specification, the “average particle diameter” relating to the spray particles is a value obtained by image analysis of an observation image of the structure in a cross section substantially perpendicular to the base material of the spray coating. Specifically, the observation image obtained by observing a cross-sectional structure substantially perpendicular to the base material of the thermal spray coating with a microscope with a predetermined magnification is binarized to separate the pore portion and the solid phase portion. By analyzing this using image analysis software, it is a value obtained as an arithmetic average value of equivalent circle diameters for 100 or more sprayed particles.
さらに、ここに開示される発明は、基材の表面に上記の溶射皮膜が備えられている、溶射皮膜付基材をも提供する。かかる溶射皮膜付基材は、基材の表面が微細で緻密な組織のセラミックス材料でコーティングされていることから、基材にセラミックス材料のバルクに近い機能を付与することが可能とされ得る。
Furthermore, the invention disclosed herein also provides a substrate with a thermal spray coating, in which the above thermal spray coating is provided on the surface of the substrate. Such a base material with a thermal spray coating may be capable of imparting a function close to the bulk of the ceramic material to the base material since the surface of the base material is coated with a ceramic material having a fine and dense structure.
以下、適宜図面を参照し、本発明の溶射材料について説明する。なお、本明細書において特に言及している事項(溶射材料の形態等)以外の事項であって、本発明の実施に必要な事柄(例えば、かかる溶射材料を用いた溶射方法や溶射装置等の溶射に係る一般的事項)は、当該分野における従来技術に基づく当業者の設計事項として把握され得る。本発明は、本明細書に開示されている内容と当該分野における技術常識とに基づいて実施することができる。
Hereinafter, the thermal spray material of the present invention will be described with reference to the drawings as appropriate. It should be noted that matters other than matters specifically mentioned in the present specification (forms of thermal spray material, etc.) and matters necessary for carrying out the present invention (for example, thermal spraying method and thermal spraying device using such thermal spray material, etc.) General matters relating to thermal spraying) can be understood as design matters of those skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
ここに開示される溶射材料は、本質的に、平均粒子径が30μm以下であって、比表面積が0.5m2/g以上のセラミックス粒子を含んでいる。すなわち、かかる溶射材料は、比表面積が極めて大きいセラミックス粒子により主として構成されている。具体的には、例えば、シリカ(SiO2)の比重が2.2[g/ml]であることから、半径がr[m]の真球のシリカ粒子の比表面積は1.36/r×10-6[m2/g]で表される。したがって、例えば、半径が30[μm]の真球のシリカ粒子の比表面積は1.36/900×106[m2/g]で表される。これに対し、ここに開示される溶射材料の比表面積は0.5[m2/g]以上に規定される。このような比表面積の増大に伴い、ここに開示される溶射材料は、表面形態が3次元的に入り組んだ複雑な形状(構造)を有することになる。すなわち、実質的な寸法(例えば、表面の凹凸部分の厚み等)は、溶射材料自体の平均粒子径に拘束されることなく、大幅に低減され得る。したがって、このような極めて大きな比表面積を有することにより、融点の高いセラミックス材料であっても、比較的低温の溶射フレーム等の熱源の熱を効率良く吸収して十分な軟化および溶融が実現され得る。延いては、セラミックスからなる溶射皮膜を基材に対して付着性良く形成することが可能な溶射材料が提供される。さらに、形成される溶射皮膜の組織は、セラミックス粒子の平均粒径に依存することなく、微細なものとなり得る。
The thermal spray material disclosed here essentially includes ceramic particles having an average particle diameter of 30 μm or less and a specific surface area of 0.5 m 2 / g or more. That is, the thermal spray material is mainly composed of ceramic particles having a very large specific surface area. Specifically, for example, since the specific gravity of silica (SiO 2 ) is 2.2 [g / ml], the specific surface area of the spherical silica particles having a radius of r [m] is 1.36 / r × It is represented by 10 −6 [m 2 / g]. Therefore, for example, the specific surface area of a true spherical silica particle having a radius of 30 [μm] is represented by 1.36 / 900 × 10 6 [m 2 / g]. On the other hand, the specific surface area of the thermal spray material disclosed herein is defined to be 0.5 [m 2 / g] or more. With such an increase in specific surface area, the thermal spray material disclosed herein has a complicated shape (structure) in which the surface form is complicated three-dimensionally. That is, substantial dimensions (for example, the thickness of the uneven portions on the surface) can be significantly reduced without being restricted by the average particle diameter of the thermal spray material itself. Therefore, by having such a very large specific surface area, even a ceramic material having a high melting point can efficiently absorb heat from a heat source such as a relatively low temperature spraying frame to achieve sufficient softening and melting. . By extension, a thermal spray material capable of forming a thermal spray coating made of ceramics with good adhesion to a substrate is provided. Furthermore, the structure of the sprayed coating formed can be fine without depending on the average particle size of the ceramic particles.
また、比較的低温の溶射温度で溶射が可能とされるため、粒成長が抑制され得る溶射温度における溶射が可能とされる。加えて、融点の低い元素を含むセラミックス粒子であっても溶射により溶射材料の組成が変化され難い。したがって、形成される溶射皮膜の組成を簡便に制御することが可能となる。
かかるセラミックス粒子の比表面積は、上記範囲であれば特に制限はされないものの、より広大であることが望ましい。例えば、0.8m2/g以上とすることができ、1m2/g以上であることが好ましく、10m2/g以上であるのがより好ましい。さらには、30m2/g以上、40m2/g以上、50m2/g以上、60m2/g以上、70m2/g以上、80m2/g以上、例えば100m2/g以上とより増大されているのが望ましい。 Further, since spraying is possible at a relatively low spraying temperature, it is possible to perform spraying at a spraying temperature at which grain growth can be suppressed. In addition, even if the ceramic particles contain an element having a low melting point, the composition of the thermal spray material is hardly changed by thermal spraying. Therefore, it is possible to easily control the composition of the sprayed coating formed.
The specific surface area of the ceramic particles is not particularly limited as long as it is in the above range, but it is desirable that the specific surface area be larger. For example, it can be set to 0.8 m 2 / g or more, preferably 1 m 2 / g or more, and more preferably 10 m 2 / g or more. Furthermore, 30 m 2 / g or more, 40 m 2 / g or more, 50 m 2 / g or more, 60 m 2 / g or more, 70 m 2 / g or more, 80 m 2 / g or more, for example, more than 100 m 2 / g or more. It is desirable.
かかるセラミックス粒子の比表面積は、上記範囲であれば特に制限はされないものの、より広大であることが望ましい。例えば、0.8m2/g以上とすることができ、1m2/g以上であることが好ましく、10m2/g以上であるのがより好ましい。さらには、30m2/g以上、40m2/g以上、50m2/g以上、60m2/g以上、70m2/g以上、80m2/g以上、例えば100m2/g以上とより増大されているのが望ましい。 Further, since spraying is possible at a relatively low spraying temperature, it is possible to perform spraying at a spraying temperature at which grain growth can be suppressed. In addition, even if the ceramic particles contain an element having a low melting point, the composition of the thermal spray material is hardly changed by thermal spraying. Therefore, it is possible to easily control the composition of the sprayed coating formed.
The specific surface area of the ceramic particles is not particularly limited as long as it is in the above range, but it is desirable that the specific surface area be larger. For example, it can be set to 0.8 m 2 / g or more, preferably 1 m 2 / g or more, and more preferably 10 m 2 / g or more. Furthermore, 30 m 2 / g or more, 40 m 2 / g or more, 50 m 2 / g or more, 60 m 2 / g or more, 70 m 2 / g or more, 80 m 2 / g or more, for example, more than 100 m 2 / g or more. It is desirable.
さらに、セラミックス粒子の平均粒子径自体は、上記のとおり溶射材料の供給に適した大きさであり得る。したがって、例えば、かかる溶射材料を高速の溶射フレームに供給した場合であっても、セラミックス粒子は適度な大きさと重量を有しているために、溶射フレームに弾かれ難い。したがって、かかる点においても、溶射付着率や成膜速度を高く維持して溶射を行うことができる。また、溶射材料の供給性を高く維持することが可能なため、溶射材料の不均一な供給による溶射皮膜の品質低下の問題を抑制することができる。
Furthermore, the average particle size of the ceramic particles can be a size suitable for supplying the thermal spray material as described above. Therefore, for example, even when such a thermal spray material is supplied to a high-speed thermal spray frame, the ceramic particles have an appropriate size and weight, and thus are not easily repelled by the thermal spray frame. Therefore, also in this respect, thermal spraying can be performed while maintaining a high thermal spraying adhesion rate and film formation rate. Moreover, since it is possible to maintain the supply property of the thermal spray material high, it is possible to suppress the problem of deterioration in the quality of the thermal spray coating due to the non-uniform supply of the thermal spray material.
かかるセラミックス粒子に係る平均粒径は、30μm程度以下であれば特に制限されず、平均粒子径の下限についても特に制限はない。より小さいものとする場合には、例えば、2μm以下とすることができ、好ましくは1μm以下、例えば400nm以下とすることができる。例えば、具体的には、平均粒子径が100nm以下の、いわゆるナノ粒子とすることも可能である。しかしながら、例えば、かかるセラミックス粒子を形成する際のハンドリングを考慮した場合は、平均粒子径の下限は100nm以上とすることが好ましく、1μm以上とするのがより好ましく、例えば、5μm以上とすることが例示される。
The average particle size of the ceramic particles is not particularly limited as long as it is about 30 μm or less, and the lower limit of the average particle size is not particularly limited. In the case of a smaller one, for example, it can be 2 μm or less, preferably 1 μm or less, for example 400 nm or less. For example, specifically, so-called nanoparticles having an average particle diameter of 100 nm or less can be used. However, for example, in consideration of handling when forming such ceramic particles, the lower limit of the average particle diameter is preferably 100 nm or more, more preferably 1 μm or more, for example, 5 μm or more. Illustrated.
なお、通常、例えば平均粒子径が6μm未満程度の微細なセラミックス粒子を溶射材料として用いると、比表面積の増大に伴いその流動性が低下して皮膜形成能が低下する。そしてさらに、その質量の小ささから、かかる溶射材料をフレームやジェット気流等に載せて飛行させることが困難となり得る。これに対し、ここに開示される溶射材料では、平均粒子径が6μm未満の一次粒子に対し、その複数のものを間隙をもって3次元的に結合させている。これにより、一次粒子の形態は概ね維持しつつも、フレームやジェット気流等から弾かれないような重みづけを実現するようにしている。これによって、より平均粒子径の小さいセラミックス粒子を用いることによる利点と、より平均粒径の大きなセラミックス粒子を用いることによる利点とを両方兼ね備えた、全く新しい溶射材料が提供され得る。
Normally, when fine ceramic particles having an average particle diameter of less than about 6 μm, for example, are used as the thermal spray material, the fluidity decreases with an increase in specific surface area, and the film forming ability decreases. Furthermore, due to its small mass, it may be difficult to fly such a thermal spray material on a frame or jet stream. On the other hand, in the thermal spray material disclosed here, a plurality of particles are three-dimensionally bonded with a gap to primary particles having an average particle diameter of less than 6 μm. As a result, weighting is achieved so as not to be repelled from a frame, a jet stream, or the like while substantially maintaining the form of the primary particles. This can provide a completely new thermal spray material that has both the advantage of using ceramic particles having a smaller average particle diameter and the advantage of using ceramic particles having a larger average particle diameter.
なお、以上の溶射材料の構成成分のうち、溶射による溶射皮膜の形成に際して皮膜形成成分となり得る成分は、主として上記のセラミックス粒子であることが好ましい。なお、ここでいう「主として」とは、皮膜形成成分のうち95質量%以上を上記セラミックス粒子が占めることを意味する。好ましくは98質量%以上、より好ましくは99質量%以上、例えば、99.5質量%以上、実質的に100質量%を上記のセラミックス粒子で占めることができる。
In addition, it is preferable that the component which can become a film formation component at the time of formation of the thermal spraying film by thermal spraying among the structural components of the above thermal spraying material is mainly said ceramic particle. Here, “mainly” means that the ceramic particles occupy 95% by mass or more of the film forming component. The ceramic particles can occupy 98% by mass or more, more preferably 99% by mass or more, for example, 99.5% by mass or more, and substantially 100% by mass.
以上の溶射材料において、セラミックス粒子の組成については特に限定されない。例えば、酸化物からなるセラミックス(酸化物系セラミックス)材料や、炭化物や窒化物,ハロゲン化物、アパタイト等の非酸化物からなるセラミックス材料であってよい。
ここで、酸化物系セラミックスとしては、特に限定されることなく各種の金属の酸化物とすることができる。かかる酸化物系セラミックスを構成する金属元素としては、例えば、B,Si,Ge,Sb,Bi等の半金属元素、Mg,Ca,Sr,Ba,Zn,Al,Ga,In,Sn,Pb等の典型元素、Sc,Y,Ti,Zr,Hf,V,Nb,Ta,Cr,Mo,W,Mn,Fe,Co,Ni,Cu,Ag,Au等の遷移金属元素、La,Ce,Pr,Nd,Sm,Er,Lu等のランタノイド元素から選択される1種または2種以上が挙げられる。なかでも、Mg,Y,Ti,Zr,Cr,Mn,Fe,Zn,Al,Erから選択される1種または2種以上の元素であることが好ましい。なお、ここに開示される酸化物系セラミックスは、以上の金属元素に加えて、F,Cl,Br,I等のハロゲン元素を含むことも好ましい。 In the above sprayed material, the composition of the ceramic particles is not particularly limited. For example, it may be a ceramic material (oxide ceramic) made of oxide, or a ceramic material made of non-oxide such as carbide, nitride, halide, apatite.
Here, the oxide ceramics are not particularly limited and may be oxides of various metals. Examples of metal elements constituting such oxide ceramics include metalloid elements such as B, Si, Ge, Sb, and Bi, Mg, Ca, Sr, Ba, Zn, Al, Ga, In, Sn, and Pb. Typical elements of Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Ag, Au, and other transition metal elements, La, Ce, Pr , Nd, Sm, Er, Lu and the like, or one or more selected from lanthanoid elements. Especially, it is preferable that it is 1 type, or 2 or more types of elements selected from Mg, Y, Ti, Zr, Cr, Mn, Fe, Zn, Al, and Er. Note that the oxide-based ceramic disclosed herein preferably contains a halogen element such as F, Cl, Br, or I in addition to the above metal elements.
ここで、酸化物系セラミックスとしては、特に限定されることなく各種の金属の酸化物とすることができる。かかる酸化物系セラミックスを構成する金属元素としては、例えば、B,Si,Ge,Sb,Bi等の半金属元素、Mg,Ca,Sr,Ba,Zn,Al,Ga,In,Sn,Pb等の典型元素、Sc,Y,Ti,Zr,Hf,V,Nb,Ta,Cr,Mo,W,Mn,Fe,Co,Ni,Cu,Ag,Au等の遷移金属元素、La,Ce,Pr,Nd,Sm,Er,Lu等のランタノイド元素から選択される1種または2種以上が挙げられる。なかでも、Mg,Y,Ti,Zr,Cr,Mn,Fe,Zn,Al,Erから選択される1種または2種以上の元素であることが好ましい。なお、ここに開示される酸化物系セラミックスは、以上の金属元素に加えて、F,Cl,Br,I等のハロゲン元素を含むことも好ましい。 In the above sprayed material, the composition of the ceramic particles is not particularly limited. For example, it may be a ceramic material (oxide ceramic) made of oxide, or a ceramic material made of non-oxide such as carbide, nitride, halide, apatite.
Here, the oxide ceramics are not particularly limited and may be oxides of various metals. Examples of metal elements constituting such oxide ceramics include metalloid elements such as B, Si, Ge, Sb, and Bi, Mg, Ca, Sr, Ba, Zn, Al, Ga, In, Sn, and Pb. Typical elements of Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Ag, Au, and other transition metal elements, La, Ce, Pr , Nd, Sm, Er, Lu and the like, or one or more selected from lanthanoid elements. Especially, it is preferable that it is 1 type, or 2 or more types of elements selected from Mg, Y, Ti, Zr, Cr, Mn, Fe, Zn, Al, and Er. Note that the oxide-based ceramic disclosed herein preferably contains a halogen element such as F, Cl, Br, or I in addition to the above metal elements.
酸化物系セラミックスとしては、より具体的には、例えば、アルミナ,ジルコニア,イットリア,クロミア,チタニア,コバルタイト、マグネシア,シリカ,カルシア,セリア,フェライト,スピネル,ジルコン,酸化ニッケル,酸化銀,酸化銅,酸化亜鉛,酸化ガリウム,酸化ストロンチウム,酸化スカンジウム,酸化サマリウム,酸化ビスマス、酸化ランタン,酸化ルテチウム,酸化ハフニウム,酸化バナジウム,酸化ニオブ,酸化タングステン,マンガン酸化物,酸化タンタル,酸化テルピウム,酸化ユーロピウム,酸化ネオジウム,酸化スズ,酸化アンチモン,アンチモン含有酸化スズ,酸化インジウム,スズ含有酸化インジウム,酸化ジルコニウムアルミネート,酸化ジルコニウムシリケート,酸化ハフニウムアルミネート,酸化ハフニウムシリケート,酸化チタンシリケート,酸化ランタンシリケート,酸化ランタンアルミネート,酸化イットリウムシリケート,酸化チタンシリケート,酸化タンタルシリケート等が例示される。
More specifically, the oxide ceramics include, for example, alumina, zirconia, yttria, chromia, titania, cobaltite, magnesia, silica, calcia, ceria, ferrite, spinel, zircon, nickel oxide, silver oxide, copper oxide, Zinc oxide, gallium oxide, strontium oxide, scandium oxide, samarium oxide, bismuth oxide, lanthanum oxide, lutetium oxide, hafnium oxide, vanadium oxide, niobium oxide, tungsten oxide, manganese oxide, tantalum oxide, terpium oxide, europium oxide, oxide Neodymium, tin oxide, antimony oxide, antimony-containing tin oxide, indium oxide, tin-containing indium oxide, zirconium oxide aluminate, zirconium oxide silicate, hafnium oxide aluminate, acid Hafnium silicate, titanium silicate oxide, lanthanum silicates, lanthanum oxide aluminate, yttrium oxide silicate, titanium silicate, tantalum oxide silicate, and the like.
また、非酸化物系セラミックスとしては、例えば、炭化ケイ素,炭化ホウ素等の炭化物、窒化ケイ素,窒化アルミニウム等の窒化物、フオルステライト,ステアタイト,コーディエライト,ムライト,チタン酸バリウム,チタン酸鉛,チタン酸ジルコン酸鉛,Mn-Znフェライト,Ni-Znフェライト,サイアロン等の複合化物、ハイドロキシアパタイト,リン酸カルシウム等のリン酸化合物等が例示される。
さらに、これらのセラミックス材料は、いずれか1種が単独でセラミック粒子を構成していても良いし、または2種以上が組み合わされてセラミックス粒子を構成していても良い。例えば、2種以上のセラミックス材料がセラミックス粒子に含まれる場合には、これらのセラミックス材料の一部または全部が複合酸化物を形成していても良い。このような複合化されたセラミックス粒子の例としては、例えば、具体的には、イットリア安定化ジルコニア、部分安定化ジルコニア、ガドリニウムドープセリア、ランタンドープチタン酸ジルコン酸鉛や、上記のサイアロン等の複合酸化物等が挙げられる。 Non-oxide ceramics include, for example, carbides such as silicon carbide and boron carbide, nitrides such as silicon nitride and aluminum nitride, forsterite, steatite, cordierite, mullite, barium titanate, lead titanate. , Lead zirconate titanate, Mn—Zn ferrite, Ni—Zn ferrite, sialon and other composite materials, hydroxyapatite, phosphate compounds such as calcium phosphate, and the like.
Furthermore, any one of these ceramic materials may constitute ceramic particles alone, or two or more thereof may be combined to constitute ceramic particles. For example, when two or more kinds of ceramic materials are included in the ceramic particles, some or all of these ceramic materials may form a composite oxide. Examples of such composite ceramic particles include, for example, composites such as yttria stabilized zirconia, partially stabilized zirconia, gadolinium doped ceria, lanthanum doped lead zirconate titanate, and the above sialon. An oxide etc. are mentioned.
さらに、これらのセラミックス材料は、いずれか1種が単独でセラミック粒子を構成していても良いし、または2種以上が組み合わされてセラミックス粒子を構成していても良い。例えば、2種以上のセラミックス材料がセラミックス粒子に含まれる場合には、これらのセラミックス材料の一部または全部が複合酸化物を形成していても良い。このような複合化されたセラミックス粒子の例としては、例えば、具体的には、イットリア安定化ジルコニア、部分安定化ジルコニア、ガドリニウムドープセリア、ランタンドープチタン酸ジルコン酸鉛や、上記のサイアロン等の複合酸化物等が挙げられる。 Non-oxide ceramics include, for example, carbides such as silicon carbide and boron carbide, nitrides such as silicon nitride and aluminum nitride, forsterite, steatite, cordierite, mullite, barium titanate, lead titanate. , Lead zirconate titanate, Mn—Zn ferrite, Ni—Zn ferrite, sialon and other composite materials, hydroxyapatite, phosphate compounds such as calcium phosphate, and the like.
Furthermore, any one of these ceramic materials may constitute ceramic particles alone, or two or more thereof may be combined to constitute ceramic particles. For example, when two or more kinds of ceramic materials are included in the ceramic particles, some or all of these ceramic materials may form a composite oxide. Examples of such composite ceramic particles include, for example, composites such as yttria stabilized zirconia, partially stabilized zirconia, gadolinium doped ceria, lanthanum doped lead zirconate titanate, and the above sialon. An oxide etc. are mentioned.
これらのセラミックス材料は、例えば、形成される溶射皮膜の色調を調整する目的で他の元素(例えば、移金属元素や、Na,K,Rb等の上記に例示した以外の元素等)が導入されたり、機能性を高める目的で他の元素が導入されるなどしてもよい。また、上記のセラミックス材料を構成する元素は、一部がイオンまたは錯体等の形態で含まれていても良い。
以上のセラミックス材料としては、なかでも、アルミナ、ジルコニア、イットリア、シリカ、炭化ケイ素、炭化ホウ素、窒化ケイ素、サイアロン、窒化アルミニウムおよびハイドロキシアパタイトのいずれかを含むことがより好ましい。 In these ceramic materials, for example, other elements (for example, transition metal elements, elements other than those exemplified above such as Na, K, Rb, etc.) are introduced for the purpose of adjusting the color tone of the formed thermal spray coating. Alternatively, other elements may be introduced for the purpose of enhancing functionality. A part of the elements constituting the ceramic material may be included in the form of ions or complexes.
Among these ceramic materials, it is more preferable to include any of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite.
以上のセラミックス材料としては、なかでも、アルミナ、ジルコニア、イットリア、シリカ、炭化ケイ素、炭化ホウ素、窒化ケイ素、サイアロン、窒化アルミニウムおよびハイドロキシアパタイトのいずれかを含むことがより好ましい。 In these ceramic materials, for example, other elements (for example, transition metal elements, elements other than those exemplified above such as Na, K, Rb, etc.) are introduced for the purpose of adjusting the color tone of the formed thermal spray coating. Alternatively, other elements may be introduced for the purpose of enhancing functionality. A part of the elements constituting the ceramic material may be included in the form of ions or complexes.
Among these ceramic materials, it is more preferable to include any of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite.
これらのセラミックス粒子の純度は特に制限されない。しかしながら、例えば、より機能性の高い溶射皮膜を形成する用途の場合には、意図しない物質(元素)の混入は避けることが好ましく、溶射材料の純度は高い方が好ましい。かかる観点においては、セラミックス粒子の純度は高い方が好ましい。例えば、純度が95質量%以上であることが好ましく、さらには99質量%以上、より好ましくは99.9質量%以上、例えば99.99質量%以上とすることができる。
The purity of these ceramic particles is not particularly limited. However, for example, in the case of an application for forming a thermal spray coating having a higher functionality, it is preferable to avoid mixing an unintended substance (element), and the higher the purity of the thermal spray material is preferable. From this viewpoint, it is preferable that the ceramic particles have a higher purity. For example, the purity is preferably 95% by mass or more, further 99% by mass or more, more preferably 99.9% by mass or more, for example, 99.99% by mass or more.
なお、ここに開示される溶射材料について、セラミックス粒子以外の成分が含まれていても良いし、含まれていなくても良い。例えば、かかる溶射材料は上記のとおりフレーム等への供給性が向上されているため、例えば、スラリー(サスペンション、インク、ベーストを包含する。)の形態に調製されていなくても良い。すなわち、皮膜形成成分となり得ない成分が実質的に含まれていなくても良い。しかしながら、例えば、かかる溶射材料をスラリー状に調製すべく、上記のセラミックス粒子を分散させるための分散媒や、かかる分散媒への分散性を高めるための分散剤等の添加剤が含まれていても良い。かかる分散媒の典型例としては、水や、水と水親和性アルコールとの混合溶媒等が挙げられる。また、皮膜形成成分としてセラミックス粒子以外の材料を含む場合等に、かかるセラミックス以外の材料(典型的には、金属粉末等の粒子状の材料)が含まれていても良い。
In addition, about the thermal spray material disclosed here, components other than ceramic particles may be included, or may not be included. For example, since the sprayability of the sprayed material is improved as described above, it may not be prepared in the form of a slurry (including suspension, ink, and base). That is, the component which cannot become a film formation component does not need to be substantially contained. However, for example, an additive such as a dispersion medium for dispersing the ceramic particles and a dispersant for improving dispersibility in the dispersion medium is included in order to prepare the thermal spray material in a slurry state. Also good. Typical examples of such a dispersion medium include water and a mixed solvent of water and a water-affinity alcohol. Further, when a material other than ceramic particles is included as a film forming component, a material other than such ceramics (typically, a particulate material such as metal powder) may be included.
なお、以上のような比表面積が増大されたセラミックス粒子は、その具体的な構成や製造方法等は特に制限されない。例えば、多孔質構造を有するセラミックス粒子を用いる等して上記のとおりの比表面積を実現するとともに、その平均粒子径を調整するようにしても良い。あるいは、セラミックス粒子の製造方法を微細に制御する等して、上記の通りの比表面積および平均粒子径を実現するセラミックス粒子を製造するようにしても良い。例えば、ここに開示される溶射材料の好ましい一態様として、以下の通りの構成のセラミックス粒子を用意するようにしても良い。
The specific structure and manufacturing method of the ceramic particles having an increased specific surface area as described above are not particularly limited. For example, the specific surface area as described above may be realized by using ceramic particles having a porous structure, and the average particle diameter may be adjusted. Or you may make it manufacture the ceramic particle which implement | achieves the above-mentioned specific surface area and average particle diameter by controlling the manufacturing method of ceramic particle finely. For example, as a preferred embodiment of the thermal spray material disclosed herein, ceramic particles having the following configuration may be prepared.
すなわち、一次粒子が間隙をもって3次元的に結合されてなる二次粒子の形態を有するセラミックス粒子により構成することである。図1は、かかるセラミックス粒子の一形態を例示するSEM像であり、図2はその拡大像である。このような構成のセラミックス粒子によると、一次粒子が微細で、かつ間隙を持って結合されているために、上記のとおりの極めて大きな比表面積を実現することができる。そして、かかるナノメートルサイズの一次粒子の粒径と、これに伴う大きな比表面積に基づき、このセラミックス粒子は比較的低温でも溶融させることができる。
この一次粒子の平均粒子径については特に限定されないものの、例えば、6μm未満であることが好ましい。このように一次粒子の平均粒子径を微細にすることで、より一層緻密で微細な組織を有する溶射皮膜を形成することが可能となる。かかる一次粒子の平均粒子径は、5μm以下であることが好ましく、例えば、1μm以下であるのがより好ましい。 That is, it is composed of ceramic particles having a form of secondary particles in which primary particles are three-dimensionally bonded with a gap. FIG. 1 is an SEM image illustrating an embodiment of such ceramic particles, and FIG. 2 is an enlarged image thereof. According to the ceramic particles having such a configuration, since the primary particles are fine and bonded with a gap, an extremely large specific surface area as described above can be realized. And based on the particle diameter of such nanometer-sized primary particles and the large specific surface area associated therewith, the ceramic particles can be melted even at a relatively low temperature.
The average particle diameter of the primary particles is not particularly limited, but is preferably less than 6 μm, for example. Thus, by making the average particle diameter of the primary particles fine, it becomes possible to form a sprayed coating having a finer and finer structure. The average particle diameter of such primary particles is preferably 5 μm or less, and more preferably 1 μm or less, for example.
この一次粒子の平均粒子径については特に限定されないものの、例えば、6μm未満であることが好ましい。このように一次粒子の平均粒子径を微細にすることで、より一層緻密で微細な組織を有する溶射皮膜を形成することが可能となる。かかる一次粒子の平均粒子径は、5μm以下であることが好ましく、例えば、1μm以下であるのがより好ましい。 That is, it is composed of ceramic particles having a form of secondary particles in which primary particles are three-dimensionally bonded with a gap. FIG. 1 is an SEM image illustrating an embodiment of such ceramic particles, and FIG. 2 is an enlarged image thereof. According to the ceramic particles having such a configuration, since the primary particles are fine and bonded with a gap, an extremely large specific surface area as described above can be realized. And based on the particle diameter of such nanometer-sized primary particles and the large specific surface area associated therewith, the ceramic particles can be melted even at a relatively low temperature.
The average particle diameter of the primary particles is not particularly limited, but is preferably less than 6 μm, for example. Thus, by making the average particle diameter of the primary particles fine, it becomes possible to form a sprayed coating having a finer and finer structure. The average particle diameter of such primary particles is preferably 5 μm or less, and more preferably 1 μm or less, for example.
そして、一次粒子の平均粒子径は、さらには500nm以下であるのが好ましく、例えば、100nm以下、50nm以下、30nm以下、20nm以下、10nm以下のナノ粒子とすることができる。このように一次粒子の平均粒子径を微細にすることで、例えば、かかる溶射材料を構成するセラミック材料自体の融点よりも低い温度で軟化又は溶融させることができる。このことは、これまでに予想されていない、全く新しい知見であり得る。したがって、かかる溶射材料は、例えば、低温プロセスによる溶射法に特に好適に供することができる。また、このような低温プロセスによっても、セラミックからなる溶射皮膜を、例えば、付着性よく、緻密なものとして、高品質に形成することができる。また、低温プロセスによると、ナノメートルサイズの一次粒子が粗大化するのを確実に防止することもできる。このような低温プロセスにより形成される溶射皮膜は、上記のセラミック粒子における一次粒子の寸法に由来したより一層微細で緻密な組織を有するものとなり得る。これにより、例えば、当該セラミックス材料のバルクに近い特性を有する溶射皮膜の形成が可能とされ得る。
The average particle diameter of the primary particles is further preferably 500 nm or less, for example, nanoparticles of 100 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 10 nm or less can be obtained. Thus, by making the average particle diameter of the primary particles fine, for example, it can be softened or melted at a temperature lower than the melting point of the ceramic material itself constituting the thermal spray material. This can be a completely new finding that has not been anticipated. Therefore, such a thermal spray material can be particularly suitably used for, for example, a thermal spraying method using a low temperature process. In addition, even with such a low temperature process, a thermal spray coating made of ceramic can be formed with high quality, for example, as a dense one with good adhesion. In addition, the low temperature process can reliably prevent the nanometer-sized primary particles from becoming coarse. The thermal spray coating formed by such a low temperature process can have a finer and denser structure derived from the size of the primary particles in the ceramic particles. Thereby, for example, it may be possible to form a thermal spray coating having characteristics close to the bulk of the ceramic material.
なお、特に限定されるものではないが、上記の微細な一次粒子を結合させた二次粒子としてのセラミックス粒子については、例えば、セラミックス粒子の平均粒子径に対する一次粒子の平均粒子径の大きさがより小さいほうが、より上述の利点をより好適に反映し得るセラミックス粒子を実現し得るために好ましい。例えば、セラミックス粒子の平均粒子径をRaとし、一次粒子の平均粒子径をraとすると、これらの比ra/Raが小さいほうが好適である。例えば、ra/Raの値は、0.1以下であるのが好ましく、0.05以下であるのがより好ましく、例えば、0.01以下、さらには0.005以下であるのがより望ましい。
Although not particularly limited, for the ceramic particles as the secondary particles combined with the fine primary particles described above, for example, the average particle size of the primary particles relative to the average particle size of the ceramic particles is The smaller one is preferable because ceramic particles that can better reflect the above-described advantages can be realized. For example, when the average particle diameter of ceramic particles is Ra and the average particle diameter of primary particles is ra, it is preferable that the ratio ra / Ra is smaller. For example, the value of ra / Ra is preferably 0.1 or less, more preferably 0.05 or less, for example, 0.01 or less, and even more preferably 0.005 or less.
一方で、従来より、例えば、図4に例示したように、いわゆる「造粒-焼結粒子」等として、一次粒子が結合されてなる二次粒子からなる溶射材料が知られてもいる。しかしながら、図3から明らかなように、従来の造粒-焼結粒子は、一次粒子の平均粒子径が比較的大きく(例えば、6μm以上)、例えばその比表面積を増大させることやその効果については全く考慮されていなかった。そのため、従来の造粒-焼結粒子の比表面積は典型的には0.4m2/g以下程度と、0.5m2/g以上を実現し得るものではなかった。かかる観点からも、ここに開示されるセラミックス粒子の形態の特性は、これまでに見られない斬新なものであり得る。
On the other hand, conventionally, for example, as illustrated in FIG. 4, as a so-called “granulated-sintered particle” or the like, a thermal spray material composed of secondary particles formed by bonding primary particles is also known. However, as is apparent from FIG. 3, the conventional granulated-sintered particles have a relatively large average particle diameter of primary particles (for example, 6 μm or more). It was not considered at all. For this reason, the specific surface area of conventional granulated-sintered particles is typically about 0.4 m 2 / g or less, and cannot be realized to be 0.5 m 2 / g or more. From this point of view, the characteristics of the morphology of the ceramic particles disclosed herein can be a novel one that has not been seen so far.
このような、より微細な一次粒子が結合されてなるセラミックス粒子は、作製方法等は特に制限されない。例えば、公知の乾式造粒あるいは湿式造粒等の造粒方法を利用して作製することができる。かかる造粒方法としては、例えば、一例として、転動造粒法、流動層造粒法、撹枠造粒法、破砕造粒法、溶融造粒法、噴霧造粒法、マイクロエマルション造粒法等が挙げられる。なかでも好適な造粒方法として、噴霧造粒法が挙げられる。
Such ceramic particles to which finer primary particles are bonded are not particularly limited in the production method. For example, it can be produced using a known granulation method such as dry granulation or wet granulation. Examples of such granulation methods include, for example, rolling granulation method, fluidized bed granulation method, stirring frame granulation method, crushing granulation method, melt granulation method, spray granulation method, microemulsion granulation method Etc. Among these, a spray granulation method is a preferable granulation method.
噴霧造粒法によると、例えば、一例として、以下の手順でかかるセラミックス粒子を作成することができる。すなわち、まず、一次粒子を構成し得るセラミックスの超微粒子(例えば、直径が数nm(例えば1nm)~100nm程度のナノ粒子であり得る。)を用意し、その表面を保護剤等により安定化させる。そしてかかる安定化されたセラミックスの超微粒子を、必要に応じて、例えば有機材料等からなるスペーサー超微粒子や、バインダ等とともに適切な溶媒に分散させて噴霧液を用意する。一次粒子の溶媒への分散には、例えば、ホモジナイザー、翼式撹拌機等の混合機、分散機等を用いて実施することができる。そしてこの噴霧液を、超音波噴霧機等を利用して噴霧することで、セラミックスの超微粒子を複数含む適切なサイズの液滴を形成する。かかる液滴を、例えば、気流に載せて連続炉を通過させる。すると、液滴は、連続炉内を搬送されながら、炉内の比較的上流に設けられる低温ゾーンで乾燥されて溶媒成分が除去され、次いで、炉内の比較的下流に設けられる高温ゾーンで焼成される。これにより、一次粒子が間隙をもって結合された二次粒子の形態のセラミックス粒子を得ることができる。
According to the spray granulation method, for example, such ceramic particles can be prepared by the following procedure as an example. That is, first, ultrafine ceramic particles (for example, nanoparticles having a diameter of several nanometers (eg, 1 nm) to 100 nm) that can form primary particles are prepared, and the surface thereof is stabilized with a protective agent or the like. . Then, the stabilized ultrafine particles of the ceramics are dispersed in an appropriate solvent together with spacer ultrafine particles made of, for example, an organic material, a binder, or the like as necessary to prepare a spray solution. The primary particles can be dispersed in the solvent using, for example, a mixer such as a homogenizer or a blade-type stirrer, a disperser, or the like. Then, by spraying this spray liquid using an ultrasonic sprayer or the like, droplets of an appropriate size including a plurality of ceramic ultrafine particles are formed. Such droplets are, for example, placed in an air stream and passed through a continuous furnace. Then, while being transported in the continuous furnace, the droplets are dried in a low temperature zone provided relatively upstream in the furnace to remove the solvent component, and then fired in a high temperature zone provided relatively downstream in the furnace. Is done. Thereby, ceramic particles in the form of secondary particles in which the primary particles are bonded with a gap can be obtained.
なお、上記の作製工程において、液滴が乾燥された状態では、例えば、セラミックスの超微粒子とスペーサー超微粒子とが均一な混合状態でバインダにより結着されて混合粒子を構成している。そして、この混合粒子が焼成されることで、スペーサー超微粒子およびバインダが消失する(燃えぬける)とともに、セラミックスの超微粒子が焼結されることで、一次粒子が間隙をもって結合された形態のセラミックス粒子が形成される。なお、焼結に際し、セラミックスの超微粒子は一部が液相となって他の粒子との結合に寄与するため、一般に、出発材料の超微粒子よりも一次粒子の平均粒子径は大きくなる。また、乾燥から焼結までの間に、セラミックス以外の成分の消失および焼成によるセラミックス超微粒子の焼き締まりなどから、液滴のサイズよりも得られるセラミックス粒子の平均粒子径のほうが大幅に小さくなる。これら、セラミックス粒子および一次粒子の平均粒子径や、一次粒子間に形成される間隙の大きさおよび割合は、所望のセラミックス粒子の形態に応じて適宜設計することができる。
In the above production process, when the droplets are dried, for example, ceramic ultrafine particles and spacer ultrafine particles are bound by a binder in a uniform mixed state to form mixed particles. When the mixed particles are fired, the spacer ultrafine particles and the binder disappear (burn out), and the ceramic ultrafine particles are sintered so that the primary particles are bonded with a gap. Is formed. During sintering, some of the ceramic ultrafine particles are in a liquid phase and contribute to bonding with other particles, so that the average particle diameter of the primary particles is generally larger than that of the starting ultrafine particles. In addition, the average particle diameter of the ceramic particles obtained is considerably smaller than the size of the droplets due to the disappearance of components other than the ceramic and the sintering of the ceramic ultrafine particles due to firing during the period from drying to sintering. The average particle diameter of these ceramic particles and primary particles and the size and ratio of the gaps formed between the primary particles can be appropriately designed according to the desired form of the ceramic particles.
また、ここに開示される溶射材料の他の好ましい一態様として、以下の通りの構成のセラミックス粒子を用意するようにしても良い。すなわち、ゼオライト構造やメソポーラス構造に代表される微多孔質構造を有するセラミックス粒子により構成することである。かかる微多孔質構造を有するセラミックス材料としては、例えば、いわゆるメソポーラス材料と呼ばれる、直径2nm~50nmの細孔(メソ孔)を有するセラミックス材料からなる微多孔質構造体を用いることができる。かかる微多孔質構造体は、例えば、構造規定性両親媒性物質(典型的には、ブロックコポリマーや界面活性剤等)を鋳型とし、その表面に自己組織化プロセスやゾルゲルプロセス等を利用して、目的の金属のアルコキシド等のセラミックス前駆体からなる微多孔質構造体を形成し、その後、鋳型を除去することで形成することができる。かかる微多孔質構造を有するセラミックス材料としては、特に限定されるものではないが、例えば、メソポーラスシリカ、メソポーラスチタニア、メソポーラスアルミナ、メソポーラスアルミノシリケート等が例示される。なお、本明細書においては、かかる微多孔質構造体として、上記のメソポーラス材料の他に、直径2nm以下の細孔(マイクロ孔)や、直径50nm以上の細孔(マクロ孔)を有するセラミックス材料等をも包含し得る。
Further, as another preferred embodiment of the thermal spray material disclosed herein, ceramic particles having the following configuration may be prepared. That is, it is composed of ceramic particles having a microporous structure typified by a zeolite structure and a mesoporous structure. As the ceramic material having such a microporous structure, for example, a so-called mesoporous material called a microporous structure made of a ceramic material having pores (mesopores) having a diameter of 2 nm to 50 nm can be used. Such a microporous structure uses, for example, a structure-defining amphiphile (typically, a block copolymer, a surfactant, etc.) as a template, and uses a self-assembly process or a sol-gel process on its surface. It can be formed by forming a microporous structure made of a ceramic precursor such as an alkoxide of the target metal and then removing the template. The ceramic material having such a microporous structure is not particularly limited, and examples thereof include mesoporous silica, mesoporous titania, mesoporous alumina, and mesoporous aluminosilicate. In the present specification, as such a microporous structure, in addition to the above mesoporous material, a ceramic material having pores (micropores) having a diameter of 2 nm or less and pores (macropores) having a diameter of 50 nm or more. Etc. may also be included.
さらに、ここに開示される溶射材料は、平均真円度が1.5未満(例えば、1以上1.5未満)のセラミックス粒子を含んでいるのが好ましい。なお、かかる平均真円度は、比較的粒径の小さいセラミックス粒子の平均真球度を間接的に表し得る指標として採用されたものであり、当該セラミックス粒子を任意の方向から平面視した場合の平均真円度を意味している。したがって、かかる平均真円度は、当該セラミックス粒子が、必ずしも二次元的に真円に近い形態であることを意図するものではなく、本質的には、三次元的に真球に近い形態であることを意図するものである。
Further, the thermal spray material disclosed herein preferably contains ceramic particles having an average roundness of less than 1.5 (for example, 1 or more and less than 1.5). The average roundness is employed as an index that can indirectly represent the average sphericity of ceramic particles having a relatively small particle diameter. When the ceramic particles are viewed in plan from an arbitrary direction, Means roundness. Therefore, this average roundness does not necessarily mean that the ceramic particles are two-dimensionally close to a perfect circle, but is essentially three-dimensionally close to a perfect sphere. Is intended.
従来の溶射材料において、球形化処理が施されていないセラミックス粒子は、結晶性が高いことから結晶系の外形がそのまま粒子の形態となって表れやすい傾向があった。とりわけ、粉砕物であるセラミックス粒子は結晶面に沿って破砕されるためにその傾向が強かった。また、理想的な結晶系の外形を示さない場合であっても、特定の結晶面が組み合わされてなる多面体に近い形態をその外形に表し得るものであった。したがって、結晶系に由来する稜や隅角(頂点であり得る)や角部を有するセラミックス粒子からなる溶射材料は、供給装置や溶射ガンからフレームに供給されるまでの間に、供給装置や溶射ガンの表面に稜や隅角、角部等が引っかかったり、セラミックス粒子同士が互いにかみ合ったりして、流動性が低下しがちであった。
これに対し、上記のようにセラミックス粒子の外形が真球に近くなり、例えば、当該粒子を構成するセラミックスの結晶性を反映した結晶面や稜、隅角、角部等の影響が低減されることで、かかるセラミックス粒子の流動性を著しく高めることができる。換言すると、ここに開示される二次粒子の形態を有する溶射材料において、一次粒子は、セラミック材料の高い結晶性が反映された形態であってよく、例えば、角柱状、塊状等の外形であっても、上記の平均真円度を満たすことで、高い流動性を確保することが可能とされる。なお、かかる平均真円度は、例えば、平均アスペクト比等の指標では表し得ないレベルの平均真球度を反映し得る指標であり得る。これにより、溶射に際して、供給装置内の流動性や、溶射ガンへの供給性が高められるとともに、溶射フレームやガス等の中心部への溶射材料の供給を好適に行うことができる、溶射材料が実現される。かかるセラミックス粒子の平均真円度は、可能な限り1に近いことが好ましく、1以上の値であり得る。また、平均真円度は、1.4以下であるのが好ましく、1.2以下がより好ましく、1.15以下、例えば、1.1以下であり得る。 In conventional thermal spray materials, ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are. In particular, the ceramic particles as a pulverized product were crushed along the crystal plane, and the tendency was strong. Further, even when the ideal crystal-type outer shape is not shown, a shape close to a polyhedron formed by combining specific crystal planes can be expressed in the outer shape. Therefore, the thermal spray material made of ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame. Ridges, corners, corners, and the like are caught on the surface of the gun, and ceramic particles tend to mesh with each other, which tends to reduce fluidity.
On the other hand, as described above, the outer shape of the ceramic particles is close to a true sphere, and for example, the influence of crystal planes, ridges, corners, corners, etc. reflecting the crystallinity of the ceramics constituting the particles is reduced. Thereby, the fluidity | liquidity of this ceramic particle can be improved significantly. In other words, in the thermal spray material having the form of the secondary particles disclosed herein, the primary particles may have a form reflecting the high crystallinity of the ceramic material, for example, an outer shape such as a prismatic shape or a lump shape. However, high fluidity can be secured by satisfying the above average roundness. The average roundness can be an index that can reflect the average sphericity at a level that cannot be expressed by an index such as an average aspect ratio. As a result, the thermal spray material that can improve the fluidity in the supply device and the supply capability to the thermal spray gun during thermal spraying and can suitably supply the thermal spray material to the center of the thermal spray frame, gas, etc. Realized. The average roundness of such ceramic particles is preferably as close to 1 as possible, and may be a value of 1 or more. The average roundness is preferably 1.4 or less, more preferably 1.2 or less, and may be 1.15 or less, for example, 1.1 or less.
これに対し、上記のようにセラミックス粒子の外形が真球に近くなり、例えば、当該粒子を構成するセラミックスの結晶性を反映した結晶面や稜、隅角、角部等の影響が低減されることで、かかるセラミックス粒子の流動性を著しく高めることができる。換言すると、ここに開示される二次粒子の形態を有する溶射材料において、一次粒子は、セラミック材料の高い結晶性が反映された形態であってよく、例えば、角柱状、塊状等の外形であっても、上記の平均真円度を満たすことで、高い流動性を確保することが可能とされる。なお、かかる平均真円度は、例えば、平均アスペクト比等の指標では表し得ないレベルの平均真球度を反映し得る指標であり得る。これにより、溶射に際して、供給装置内の流動性や、溶射ガンへの供給性が高められるとともに、溶射フレームやガス等の中心部への溶射材料の供給を好適に行うことができる、溶射材料が実現される。かかるセラミックス粒子の平均真円度は、可能な限り1に近いことが好ましく、1以上の値であり得る。また、平均真円度は、1.4以下であるのが好ましく、1.2以下がより好ましく、1.15以下、例えば、1.1以下であり得る。 In conventional thermal spray materials, ceramic particles that have not been spheroidized have a high crystallinity, and thus have a tendency that the outer shape of the crystal system tends to appear in the form of particles as they are. In particular, the ceramic particles as a pulverized product were crushed along the crystal plane, and the tendency was strong. Further, even when the ideal crystal-type outer shape is not shown, a shape close to a polyhedron formed by combining specific crystal planes can be expressed in the outer shape. Therefore, the thermal spray material made of ceramic particles having ridges, corners (which may be vertices) or corners derived from the crystal system is supplied from the supply device or the spray gun to the frame before being supplied to the frame. Ridges, corners, corners, and the like are caught on the surface of the gun, and ceramic particles tend to mesh with each other, which tends to reduce fluidity.
On the other hand, as described above, the outer shape of the ceramic particles is close to a true sphere, and for example, the influence of crystal planes, ridges, corners, corners, etc. reflecting the crystallinity of the ceramics constituting the particles is reduced. Thereby, the fluidity | liquidity of this ceramic particle can be improved significantly. In other words, in the thermal spray material having the form of the secondary particles disclosed herein, the primary particles may have a form reflecting the high crystallinity of the ceramic material, for example, an outer shape such as a prismatic shape or a lump shape. However, high fluidity can be secured by satisfying the above average roundness. The average roundness can be an index that can reflect the average sphericity at a level that cannot be expressed by an index such as an average aspect ratio. As a result, the thermal spray material that can improve the fluidity in the supply device and the supply capability to the thermal spray gun during thermal spraying and can suitably supply the thermal spray material to the center of the thermal spray frame, gas, etc. Realized. The average roundness of such ceramic particles is preferably as close to 1 as possible, and may be a value of 1 or more. The average roundness is preferably 1.4 or less, more preferably 1.2 or less, and may be 1.15 or less, for example, 1.1 or less.
なお、このセラミックス粒子の外形については、平面視における平均アスペクト比が1.4未満であるとより好ましい。というのは、上記のとおり、平均真円度がより1に近いセラミックス粒子において、真円度は、セラミックス粒子の全体的な形態よりも表面形態をより反映するものであり得る。換言すると、上述の真円度は、真円に近いセラミックス粒子を評価する場合については、セラミックス粒子の平面視における輪郭線がミクロなレベルで複雑になればなるほど、その値はセラミックス粒子の全体の外形の変化の度合いを超えて大きくなりやすい傾向にある。したがって、真円度に加えて、さらにアスペクト比によりセラミックス粒子の外形について規定することで、全体としての外形がより真球に近い、すなわち平面視においては真円に近い、セラミックス粒子とすることができる。
かかる平均アスペクト比は、溶射材料の流動性を考慮すると、1.3以下であるのが好ましく、1.2以下であるのがより好ましい。さらには、例えば、1.15以下とすることができ、1あるいは1により近いことが望ましい。 In addition, about the external shape of this ceramic particle, it is more preferable in the planar view that the average aspect-ratio is less than 1.4. This is because, as described above, in ceramic particles having an average roundness closer to 1, the roundness may reflect the surface morphology more than the overall morphology of the ceramic particles. In other words, in the case of evaluating ceramic particles that are close to a perfect circle, the roundness described above becomes more complex as the contour line in the plan view of the ceramic particles becomes more complex at a micro level. It tends to be larger than the degree of change of the outer shape. Therefore, by defining the outer shape of the ceramic particles by the aspect ratio in addition to the roundness, it is possible to obtain ceramic particles whose overall outer shape is closer to a perfect sphere, that is, closer to a perfect circle in plan view. it can.
The average aspect ratio is preferably 1.3 or less, and more preferably 1.2 or less in consideration of the fluidity of the thermal spray material. Further, for example, it can be set to 1.15 or less, and is preferably 1 or closer to 1.
かかる平均アスペクト比は、溶射材料の流動性を考慮すると、1.3以下であるのが好ましく、1.2以下であるのがより好ましい。さらには、例えば、1.15以下とすることができ、1あるいは1により近いことが望ましい。 In addition, about the external shape of this ceramic particle, it is more preferable in the planar view that the average aspect-ratio is less than 1.4. This is because, as described above, in ceramic particles having an average roundness closer to 1, the roundness may reflect the surface morphology more than the overall morphology of the ceramic particles. In other words, in the case of evaluating ceramic particles that are close to a perfect circle, the roundness described above becomes more complex as the contour line in the plan view of the ceramic particles becomes more complex at a micro level. It tends to be larger than the degree of change of the outer shape. Therefore, by defining the outer shape of the ceramic particles by the aspect ratio in addition to the roundness, it is possible to obtain ceramic particles whose overall outer shape is closer to a perfect sphere, that is, closer to a perfect circle in plan view. it can.
The average aspect ratio is preferably 1.3 or less, and more preferably 1.2 or less in consideration of the fluidity of the thermal spray material. Further, for example, it can be set to 1.15 or less, and is preferably 1 or closer to 1.
また、このセラミックス粒子については、平均フラクタル次元が1.07未満であることも好ましい態様の一つである。というのは、かかるセラミックス粒子は、表面形態がミクロなレベルで複雑なものであり得る。したがって、かかる粒子表面の複雑な形態を更に多様な指標で規定することで、外形がより真球に近いセラミックス粒子とすることができる。フラクタル次元は、個々の粒子表面の複雑な形態を測るために広く一般に利用される指標であり、平均フラクタル次元はここに開示されるセラミックス粒子の表面の滑らかさを指し図るには好適な指標であり得る。平均フラクタル次元を1.07未満に規定することで、さらに流動性の向上された溶射材料を実現し得る。
かかる平均フラクタル次元は、溶射材料の流動性を考慮すると、1.05以下であるのが好ましく、1.03以下であるのがより好ましい。さらには、例えば、1.02以下、1.01以下とすることができ、1あるいは1により近いことが望ましい。 In addition, regarding the ceramic particles, an average fractal dimension is preferably less than 1.07. This is because such ceramic particles may have a complicated surface morphology at a micro level. Therefore, by defining the complicated shape of the particle surface with more various indexes, the outer shape of the ceramic particle can be made closer to a true sphere. The fractal dimension is an index that is widely used to measure the complex morphology of individual particle surfaces, and the average fractal dimension is a suitable index for indicating the smoothness of the surface of ceramic particles disclosed herein. possible. By defining the average fractal dimension to be less than 1.07, it is possible to realize a thermal spray material with further improved fluidity.
The average fractal dimension is preferably 1.05 or less and more preferably 1.03 or less in consideration of the fluidity of the thermal spray material. Furthermore, for example, it can be set to 1.02 or less and 1.01 or less, and is desirably 1 or closer to 1.
かかる平均フラクタル次元は、溶射材料の流動性を考慮すると、1.05以下であるのが好ましく、1.03以下であるのがより好ましい。さらには、例えば、1.02以下、1.01以下とすることができ、1あるいは1により近いことが望ましい。 In addition, regarding the ceramic particles, an average fractal dimension is preferably less than 1.07. This is because such ceramic particles may have a complicated surface morphology at a micro level. Therefore, by defining the complicated shape of the particle surface with more various indexes, the outer shape of the ceramic particle can be made closer to a true sphere. The fractal dimension is an index that is widely used to measure the complex morphology of individual particle surfaces, and the average fractal dimension is a suitable index for indicating the smoothness of the surface of ceramic particles disclosed herein. possible. By defining the average fractal dimension to be less than 1.07, it is possible to realize a thermal spray material with further improved fluidity.
The average fractal dimension is preferably 1.05 or less and more preferably 1.03 or less in consideration of the fluidity of the thermal spray material. Furthermore, for example, it can be set to 1.02 or less and 1.01 or less, and is desirably 1 or closer to 1.
加えて、ここに開示される溶射材料については、安息角が35°未満であることも好ましい態様の一つである。安息角は、従来より粉体の流動性を示すために広く採用されてきた指標の一つであり得る。そして、例えば、溶射材料が供給装置内および溶射装置内を搬送される際の、自発的な流動性を実際的に反映し得る指標であり得る。したがって、かかる安息角を小さく規定することで、流動性が高い溶射材料を実現することができる。延いては、均質な溶射皮膜をより生産性良く形成することができる溶射材料であり得る。
かかる安息角は、溶射材料の流動性を考慮すると、34°以下であるのが好ましく、32°以下であるのがより好ましい。さらには、例えば、30°以下とすることもできる。安息角の下限に特に制限はないが、安息角が小さすぎると溶射材料が飛散し易くなったり、溶射材料の供給量の制御が困難になったりする場合がある。したがって、おおよその目安として、安息角は20°以上とすることが例示される。 In addition, for the thermal spray material disclosed herein, it is also a preferred embodiment that the angle of repose is less than 35 °. The angle of repose can be one of the indexes that have been widely adopted to show the fluidity of powders. For example, it may be an index that can actually reflect the spontaneous fluidity when the thermal spray material is conveyed in the supply apparatus and the thermal spray apparatus. Therefore, by defining the angle of repose to be small, a spray material having high fluidity can be realized. As a result, it can be a thermal spray material capable of forming a homogeneous thermal spray coating with higher productivity.
In consideration of the fluidity of the thermal spray material, the angle of repose is preferably 34 ° or less, and more preferably 32 ° or less. Further, for example, the angle may be 30 ° or less. The lower limit of the angle of repose is not particularly limited. However, if the angle of repose is too small, the sprayed material may be easily scattered or the supply amount of the sprayed material may be difficult to control. Therefore, as an approximate guide, the angle of repose is exemplified as 20 ° or more.
かかる安息角は、溶射材料の流動性を考慮すると、34°以下であるのが好ましく、32°以下であるのがより好ましい。さらには、例えば、30°以下とすることもできる。安息角の下限に特に制限はないが、安息角が小さすぎると溶射材料が飛散し易くなったり、溶射材料の供給量の制御が困難になったりする場合がある。したがって、おおよその目安として、安息角は20°以上とすることが例示される。 In addition, for the thermal spray material disclosed herein, it is also a preferred embodiment that the angle of repose is less than 35 °. The angle of repose can be one of the indexes that have been widely adopted to show the fluidity of powders. For example, it may be an index that can actually reflect the spontaneous fluidity when the thermal spray material is conveyed in the supply apparatus and the thermal spray apparatus. Therefore, by defining the angle of repose to be small, a spray material having high fluidity can be realized. As a result, it can be a thermal spray material capable of forming a homogeneous thermal spray coating with higher productivity.
In consideration of the fluidity of the thermal spray material, the angle of repose is preferably 34 ° or less, and more preferably 32 ° or less. Further, for example, the angle may be 30 ° or less. The lower limit of the angle of repose is not particularly limited. However, if the angle of repose is too small, the sprayed material may be easily scattered or the supply amount of the sprayed material may be difficult to control. Therefore, as an approximate guide, the angle of repose is exemplified as 20 ° or more.
なお、特に制限されるものではないが、ここに開示される溶射材料は、フローファンクションが3以上であることが好ましい。
上記の安息角は、無荷重状態での溶射材料の流動性を評価し得る指標であった。一方で、このフローファンクションは、溶射材料を圧密した状態でせん断応力を測定することによりその流動特性を評価するものであって、溶射材料のハンドリング性をより実際的に表現し得る指標となり得る。したがって、かかる構成によっても、例えば、平均粒子径が30μm未満の溶射材料について流動性が高いと判断することができ、溶射皮膜をより一層生産性良く形成し得る溶射材料を提供することができる。
なお、本明細書において、「フローファンクション」は、いわゆる相対流動性指数(Relative Flow Index:RFI)とも呼ばれる値であって、内径が50mmの容器内に所定の量の溶射材料を入れ、常温常湿下、当該溶射材料に9kPaの剪断力を与えたときの溶射材料の最大主応力と単軸崩壊応力とを測定し、最大主応力の測定値を単軸崩壊応力の測定値で除することで求められる値である。このフローファンクションが大きいほど、当該溶射材料の流動性が良いことを意味する。 Although not particularly limited, the thermal spray material disclosed herein preferably has a flow function of 3 or more.
The angle of repose is an index that can evaluate the fluidity of the thermal spray material in a no-load state. On the other hand, this flow function evaluates the flow characteristics by measuring the shear stress in a compacted state of the thermal spray material, and can be an index that can more practically express the handling property of the thermal spray material. Therefore, even with such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 μm has high fluidity, and it is possible to provide a thermal spraying material that can form a thermal spray coating with higher productivity.
In the present specification, the “flow function” is a value called a so-called Relative Flow Index (RFI), and a predetermined amount of thermal spray material is placed in a container having an inner diameter of 50 mm. Measure the maximum principal stress and uniaxial collapse stress of the thermal spray material when a shearing force of 9 kPa is applied to the thermal spray material under humidity, and divide the measured value of the maximum principal stress by the measured value of the uniaxial collapse stress. This is the value obtained by. The larger the flow function, the better the fluidity of the sprayed material.
上記の安息角は、無荷重状態での溶射材料の流動性を評価し得る指標であった。一方で、このフローファンクションは、溶射材料を圧密した状態でせん断応力を測定することによりその流動特性を評価するものであって、溶射材料のハンドリング性をより実際的に表現し得る指標となり得る。したがって、かかる構成によっても、例えば、平均粒子径が30μm未満の溶射材料について流動性が高いと判断することができ、溶射皮膜をより一層生産性良く形成し得る溶射材料を提供することができる。
なお、本明細書において、「フローファンクション」は、いわゆる相対流動性指数(Relative Flow Index:RFI)とも呼ばれる値であって、内径が50mmの容器内に所定の量の溶射材料を入れ、常温常湿下、当該溶射材料に9kPaの剪断力を与えたときの溶射材料の最大主応力と単軸崩壊応力とを測定し、最大主応力の測定値を単軸崩壊応力の測定値で除することで求められる値である。このフローファンクションが大きいほど、当該溶射材料の流動性が良いことを意味する。 Although not particularly limited, the thermal spray material disclosed herein preferably has a flow function of 3 or more.
The angle of repose is an index that can evaluate the fluidity of the thermal spray material in a no-load state. On the other hand, this flow function evaluates the flow characteristics by measuring the shear stress in a compacted state of the thermal spray material, and can be an index that can more practically express the handling property of the thermal spray material. Therefore, even with such a configuration, for example, it is possible to determine that the thermal spraying material having an average particle diameter of less than 30 μm has high fluidity, and it is possible to provide a thermal spraying material that can form a thermal spray coating with higher productivity.
In the present specification, the “flow function” is a value called a so-called Relative Flow Index (RFI), and a predetermined amount of thermal spray material is placed in a container having an inner diameter of 50 mm. Measure the maximum principal stress and uniaxial collapse stress of the thermal spray material when a shearing force of 9 kPa is applied to the thermal spray material under humidity, and divide the measured value of the maximum principal stress by the measured value of the uniaxial collapse stress. This is the value obtained by. The larger the flow function, the better the fluidity of the sprayed material.
以上のとおり、ここに開示される技術により提供される溶射材料は、そこに含まれるセラミックス粒子の平均粒子径が比較的大きく維持されているため、例えば、溶射フレーム等への熱源の供給性(流動性を包含する。)が高く確保されている。また、比表面積が極めて大きく規定されているため、より低い温度で十分に軟化溶融され得るとともに、微細な組織を実現し得る。したがって、緻密で微細な組織を有する溶射皮膜を生産性良く形成することができる溶射材料であり得る。
As described above, the thermal spray material provided by the technique disclosed herein maintains a relatively large average particle diameter of the ceramic particles contained therein, and thus, for example, the heat source supplyability to the thermal spray frame or the like ( Including fluidity). Further, since the specific surface area is defined to be extremely large, it can be sufficiently softened and melted at a lower temperature, and a fine structure can be realized. Therefore, it can be a thermal spray material capable of forming a thermal spray coating having a dense and fine structure with high productivity.
また、このような溶射材料は、好適な一形態として、例えば、より微細な一次粒子が結合されてなる二次粒子としてのセラミックス粒子を含むものとして好適に実現することができる。例えば、ナノメートルサイズの一次粒子が結合された形態のセラミックス粒子であり得る。かかる二次粒子としてのセラミックス粒子によると、より微細な一次粒子の間には十分な間隙を設けることができ、セラミックス粒子は一次粒子の形態を維持しつつ二次粒子を構成していると考えることができる。したがって、例えば、かかる溶射材料を溶射に用いることで、一次粒子に相当する寸法(例えば、ナノメートルサイズ)の溶射材料を用いて溶射した場合と同様の特徴を有する高品質な溶射皮膜を形成することができる。また、融点が高いセラミックスからなる溶射材料であるにもかかわらず、より一層低温での溶射が可能となる。例えば、2000℃程度と、かかる溶射材料の融点以下の温度での溶射が可能とされ得る。さらに、例えば、かかる溶射材料を溶射に用いることで、二次粒子に相当する寸法(例えば、マイクロメートルサイズ)の溶射材料を用いた場合と同様にして、溶射を行うことができる。例えば、流動性よく溶射材料を溶射装置に供給することができ、また、高効率で、付着性のよい溶射皮膜を高い製膜速度で形成することができる。
Moreover, such a thermal spray material can be suitably realized as a suitable form, for example, including ceramic particles as secondary particles formed by bonding finer primary particles. For example, it may be ceramic particles in a form in which nanometer-sized primary particles are bonded. According to the ceramic particles as such secondary particles, it is possible to provide a sufficient gap between the finer primary particles, and the ceramic particles constitute secondary particles while maintaining the form of the primary particles. be able to. Therefore, for example, by using such a thermal spray material for thermal spraying, a high-quality thermal spray coating having the same characteristics as the case of thermal spraying using a thermal spray material having dimensions (for example, nanometer size) corresponding to primary particles is formed. be able to. Further, although it is a thermal spray material made of ceramics having a high melting point, thermal spraying at a lower temperature is possible. For example, it may be possible to perform thermal spraying at a temperature of about 2000 ° C. or lower and a temperature lower than the melting point of the thermal spray material. Further, for example, by using such a thermal spray material for thermal spraying, it is possible to perform thermal spraying in the same manner as when using a thermal spray material having a dimension (for example, micrometer size) corresponding to the secondary particles. For example, a thermal spray material can be supplied to a thermal spraying apparatus with good fluidity, and a thermal spray coating with high efficiency and good adhesion can be formed at a high film forming speed.
かかる溶射材料を例えば高速フレーム溶射法により溶射して得られる溶射皮膜は、セラミックス材料からなる溶射粒子が基材上に堆積されてなる溶射皮膜であって、基材の表面に垂直な断面におけるかかる溶射粒子の平均粒子径が5μm未満と、微細な溶融粒子が緻密に堆積して形成されるものであり得る。かかる溶射粒子の粒子径は、4μm以下であることが好ましく、3μm以下であることがより好ましく、1μm以下であること、さらには100nm以下であるのがより一層好ましい。したがって、当該溶射材料のバルクに匹敵する特性を備えたものであり得る。例えば、緻密性、絶縁性等の電気特性、耐食性、環境遮断特性等に優れた溶射皮膜であり得る。したがって、かかる溶射皮膜を備える皮膜形成品は、所望の特性を有するセラミックス粒子を含む溶射材料を用いて形成することで、広く様々な用途に好適に適用することができる。
A sprayed coating obtained by spraying such a sprayed material by, for example, a high-speed flame spraying method is a sprayed coating in which sprayed particles made of a ceramic material are deposited on a base material, and the cross section is perpendicular to the surface of the base material. When the average particle diameter of the spray particles is less than 5 μm, fine molten particles may be densely deposited. The particle size of the spray particles is preferably 4 μm or less, more preferably 3 μm or less, further preferably 1 μm or less, and even more preferably 100 nm or less. Therefore, it may have characteristics comparable to the bulk of the thermal spray material. For example, it may be a thermal spray coating excellent in electrical characteristics such as denseness and insulation, corrosion resistance, and environmental barrier properties. Therefore, a film-formed product provided with such a thermal spray coating can be suitably applied to a wide variety of uses by being formed using a thermal spray material containing ceramic particles having desired characteristics.
例えば、セラミックス粒子を酸化アルミニウムから構成することで、高い電気絶縁性、耐摩耗性および耐食性を示す溶射皮膜が得られることから、各種部材の保護皮膜等として好適に使用できる。また、例えば、セラミックス粒子を酸化イットリウムから構成することで、高い耐プラズマエロージョン性を示す溶射皮膜が得られることから、半導体デバイス製造装置等のチャンバー内部の保護皮膜等として好適に使用できる。特に、フッ素化された酸化イットリウムからセラミックス粒子を構成することで、得られる溶射皮膜は耐プラズマエロージョン性がより一層高められるために好ましい。さらに、例えば、セラミックス粒子をイットリア安定化ジルコニアから構成することで、硬質でイオン伝導性に優れている溶射皮膜が得られることから、固体酸化物型燃料電池(Solid Oxide Fuel Cel1:SOFC)の固体電解質等として好適に使用できる。このように、ここに開示される溶射 材料により、所望の用途に応じた溶射皮膜を好適に形成することができる。
For example, by forming ceramic particles from aluminum oxide, a sprayed coating exhibiting high electrical insulation, wear resistance, and corrosion resistance can be obtained, and therefore, it can be suitably used as a protective coating for various members. Further, for example, by forming ceramic particles from yttrium oxide, a thermal spray coating exhibiting high plasma erosion resistance can be obtained, and therefore, it can be suitably used as a protective coating inside a chamber of a semiconductor device manufacturing apparatus or the like. In particular, by forming ceramic particles from fluorinated yttrium oxide, the resulting sprayed coating is preferable because the plasma erosion resistance is further enhanced. Furthermore, for example, by forming ceramic particles from yttria-stabilized zirconia, a thermal spray coating that is hard and has excellent ion conductivity can be obtained, so that the solid oxide fuel cell (Solid Oxide Fuel Cel1: SOFC) solid It can be suitably used as an electrolyte or the like. Thus, the thermal spray coating according to a desired use can be suitably formed with the thermal spray coating material disclosed here.
上記の溶射材料は、特に制限なく各種の溶射方法に適用することができる。例えば、従来のように、プラズマ溶接法等の、熱源の温度が2500℃以上の高温プロセスでの溶射方法に適用することができる。かかる溶射法によると、例えば二次粒子の形態ではないセラミックス粒子を含む溶射材料を用いる場合に、かかる溶射材料を十分に軟化および溶融させることができ、高品質な溶射を行うことができる。
プラズマ溶射法とは、溶射材を軟化または溶融するための溶射熱源としてプラズマ炎を利用する溶射方法である。電極間にアークを発生させ、かかるアークにより作動ガスをプラズマ化すると、かかるプラズマ流はノズルから高温高速のプラズマジェットとなって噴出する。プラズマ溶射法は、このプラズマジェットに溶射材料を投入し、加熱、加速して基材に堆積させることで溶射皮膜を得るコーティング手法一般を包含する。なお、プラズマ溶射法は、大気中で行う大気プラズマ溶射(APS:atmospheric plasma spraying)や、大気圧よりも低い気圧で溶射を行う減圧プラズマ溶射(LPS:low pressure plasma spraying)、大気圧より高い加圧容器内でプラズマ溶射を行う加圧プラズマ溶射(high pressure plasma spraying)等の態様であり得る。プラズマ溶射によると、例えば、一例として、溶射材を2500℃~10000℃程度のプラズマジェットにより加熱および加速させることで、溶射粒子を300m/s~600m/s程度の速度にて基材へ衝突させて堆積させることができる。 The above-mentioned thermal spray material can be applied to various thermal spraying methods without particular limitation. For example, it can be applied to a thermal spraying method in a high temperature process in which the temperature of the heat source is 2500 ° C. or higher, such as a plasma welding method, as in the past. According to such a thermal spraying method, for example, when using a thermal spray material containing ceramic particles that are not in the form of secondary particles, the thermal spray material can be sufficiently softened and melted, and high-quality thermal spraying can be performed.
The plasma spraying method is a spraying method using a plasma flame as a thermal spraying heat source for softening or melting a thermal spray material. When an arc is generated between the electrodes and the working gas is converted into plasma by the arc, the plasma flow is ejected from the nozzle as a high-temperature and high-speed plasma jet. The plasma spraying method includes a general coating technique in which a thermal spray material is put into this plasma jet, heated and accelerated, and deposited on a substrate by deposition. Plasma spraying methods include atmospheric plasma spraying (APS) performed in the atmosphere, low pressure plasma spraying (LPS) performed at a pressure lower than atmospheric pressure, and pressure higher than atmospheric pressure. It may be an embodiment such as high pressure plasma spraying in which plasma spraying is performed in a pressure vessel. According to plasma spraying, for example, the thermal spray material is heated and accelerated by a plasma jet at about 2500 ° C. to 10000 ° C. to cause the thermal spray particles to collide with the substrate at a speed of about 300 m / s to 600 m / s. Can be deposited.
プラズマ溶射法とは、溶射材を軟化または溶融するための溶射熱源としてプラズマ炎を利用する溶射方法である。電極間にアークを発生させ、かかるアークにより作動ガスをプラズマ化すると、かかるプラズマ流はノズルから高温高速のプラズマジェットとなって噴出する。プラズマ溶射法は、このプラズマジェットに溶射材料を投入し、加熱、加速して基材に堆積させることで溶射皮膜を得るコーティング手法一般を包含する。なお、プラズマ溶射法は、大気中で行う大気プラズマ溶射(APS:atmospheric plasma spraying)や、大気圧よりも低い気圧で溶射を行う減圧プラズマ溶射(LPS:low pressure plasma spraying)、大気圧より高い加圧容器内でプラズマ溶射を行う加圧プラズマ溶射(high pressure plasma spraying)等の態様であり得る。プラズマ溶射によると、例えば、一例として、溶射材を2500℃~10000℃程度のプラズマジェットにより加熱および加速させることで、溶射粒子を300m/s~600m/s程度の速度にて基材へ衝突させて堆積させることができる。 The above-mentioned thermal spray material can be applied to various thermal spraying methods without particular limitation. For example, it can be applied to a thermal spraying method in a high temperature process in which the temperature of the heat source is 2500 ° C. or higher, such as a plasma welding method, as in the past. According to such a thermal spraying method, for example, when using a thermal spray material containing ceramic particles that are not in the form of secondary particles, the thermal spray material can be sufficiently softened and melted, and high-quality thermal spraying can be performed.
The plasma spraying method is a spraying method using a plasma flame as a thermal spraying heat source for softening or melting a thermal spray material. When an arc is generated between the electrodes and the working gas is converted into plasma by the arc, the plasma flow is ejected from the nozzle as a high-temperature and high-speed plasma jet. The plasma spraying method includes a general coating technique in which a thermal spray material is put into this plasma jet, heated and accelerated, and deposited on a substrate by deposition. Plasma spraying methods include atmospheric plasma spraying (APS) performed in the atmosphere, low pressure plasma spraying (LPS) performed at a pressure lower than atmospheric pressure, and pressure higher than atmospheric pressure. It may be an embodiment such as high pressure plasma spraying in which plasma spraying is performed in a pressure vessel. According to plasma spraying, for example, the thermal spray material is heated and accelerated by a plasma jet at about 2500 ° C. to 10000 ° C. to cause the thermal spray particles to collide with the substrate at a speed of about 300 m / s to 600 m / s. Can be deposited.
一方で、より微細な一次粒子が結合されてなるセラミックス粒子を含む溶射材料については、そこに含まれるセラミックス粒子を構成するセラミックス材料自体の融点よりも低い温度で溶射し得るとの特徴から、例えば、熱源の温度が2500℃以下(2500℃未満)程度の低温プロセスでの溶射方法に適用するのがその利点が如何なく発揮されるために好ましい。したがって、かかる溶射材料は、例えば、高速フレーム溶射法やフォームスプレー法等に代表される低温プロセスによる溶射法に好ましく適用することができる。すなわち、かかる溶射材料は、セラミックス粒子がより低い温度においても好適に軟化または溶融状態を実現することができ、適切な速度で飛行させることにより、基材に密着性良く付着し、より微密な溶射皮膜を形成することができる。溶射速度については、例えば、300m/s以上2000m/s以下程度を目安に適宜調整することができる。
On the other hand, with respect to the thermal spray material including ceramic particles formed by bonding finer primary particles, it can be sprayed at a temperature lower than the melting point of the ceramic material itself constituting the ceramic particles contained therein, for example, It is preferable to apply to a thermal spraying method in a low-temperature process where the temperature of the heat source is about 2500 ° C. or less (less than 2500 ° C.) because the advantages are manifested. Therefore, such a thermal spray material can be preferably applied to a thermal spraying method by a low temperature process represented by, for example, a high-speed flame spraying method or a foam spraying method. That is, such a thermal spray material can suitably realize a softened or molten state even when the ceramic particles are at a lower temperature. By flying at an appropriate speed, the thermal spray material adheres to the base material with good adhesion and becomes finer. A sprayed coating can be formed. The spraying speed can be adjusted as appropriate using, for example, about 300 m / s or more and 2000 m / s or less.
また、高速フレーム溶射法としては、例えば、酸素支燃型高速フレーム(High Velocity Oxygen Flame:HVOF)溶射法、ウォームスプレー溶射法および空気支燃型(High Velocity Air flame:HVAF)高速フレーム溶射法等を考慮することができる。
HVOF溶射法とは、燃料と酸素とを混合して高圧で燃焼させた燃焼炎を溶射のための熱源として利用するフレーム溶射法の一種である。燃焼室の圧力を高めることにより、連続した燃焼炎でありながらノズルから高速(超音速であり得る。)の高温ガス流を噴出させる。HVOF溶射法は、このガス流中に溶射材料を投入し、加熱、加速して基材に堆積させることで溶射皮膜を得るコーティング手法一般を包含する。HVOF溶射法によると、例えば、一例として、溶射材料を1800℃~2500℃の超音速燃焼炎のジェットにより溶融および加速させることで、溶射粒子を500m/s~1000m/sという高速度にて基材へ衝突させて堆積させることができる。高速フレーム溶射で使用する燃料は、アセチレン、エチレン、プロパン、プロピレンなどの炭化水素のガス燃料であってもよいし、灯油やエタノールなどの液体燃料であってもよい。また、溶射材の融点が高いほど超音速燃焼炎の温度が高い方が好ましく、この観点では、ガス燃料を用いることが好ましい。 Examples of the high-speed flame spraying method include an oxygen-flammable high-speed flame (HVOF) thermal spraying method, a warm spray thermal spraying method, and an air-flammable (High Velocity Air flame: HVAF) high-speed flame spraying method. Can be considered.
The HVOF spraying method is a kind of flame spraying method in which a combustion flame in which fuel and oxygen are mixed and burned at high pressure is used as a heat source for spraying. By increasing the pressure in the combustion chamber, a high-temperature (which may be supersonic) high-temperature gas flow is ejected from the nozzle while being a continuous combustion flame. The HVOF thermal spraying method includes a general coating technique in which a thermal spray material is put into this gas flow, and heated and accelerated to deposit it on a substrate to obtain a thermal spray coating. According to the HVOF thermal spraying method, for example, the thermal spray material is melted and accelerated with a jet of a supersonic combustion flame of 1800 ° C. to 2500 ° C., so that the thermal spray particles can be obtained at a high speed of 500 m / s to 1000 m / s. It can be deposited by colliding with the material. The fuel used in high-speed flame spraying may be a hydrocarbon gas fuel such as acetylene, ethylene, propane, or propylene, or a liquid fuel such as kerosene or ethanol. Further, the higher the melting point of the thermal spray material, the higher the temperature of the supersonic combustion flame is preferable. From this viewpoint, it is preferable to use gas fuel.
HVOF溶射法とは、燃料と酸素とを混合して高圧で燃焼させた燃焼炎を溶射のための熱源として利用するフレーム溶射法の一種である。燃焼室の圧力を高めることにより、連続した燃焼炎でありながらノズルから高速(超音速であり得る。)の高温ガス流を噴出させる。HVOF溶射法は、このガス流中に溶射材料を投入し、加熱、加速して基材に堆積させることで溶射皮膜を得るコーティング手法一般を包含する。HVOF溶射法によると、例えば、一例として、溶射材料を1800℃~2500℃の超音速燃焼炎のジェットにより溶融および加速させることで、溶射粒子を500m/s~1000m/sという高速度にて基材へ衝突させて堆積させることができる。高速フレーム溶射で使用する燃料は、アセチレン、エチレン、プロパン、プロピレンなどの炭化水素のガス燃料であってもよいし、灯油やエタノールなどの液体燃料であってもよい。また、溶射材の融点が高いほど超音速燃焼炎の温度が高い方が好ましく、この観点では、ガス燃料を用いることが好ましい。 Examples of the high-speed flame spraying method include an oxygen-flammable high-speed flame (HVOF) thermal spraying method, a warm spray thermal spraying method, and an air-flammable (High Velocity Air flame: HVAF) high-speed flame spraying method. Can be considered.
The HVOF spraying method is a kind of flame spraying method in which a combustion flame in which fuel and oxygen are mixed and burned at high pressure is used as a heat source for spraying. By increasing the pressure in the combustion chamber, a high-temperature (which may be supersonic) high-temperature gas flow is ejected from the nozzle while being a continuous combustion flame. The HVOF thermal spraying method includes a general coating technique in which a thermal spray material is put into this gas flow, and heated and accelerated to deposit it on a substrate to obtain a thermal spray coating. According to the HVOF thermal spraying method, for example, the thermal spray material is melted and accelerated with a jet of a supersonic combustion flame of 1800 ° C. to 2500 ° C., so that the thermal spray particles can be obtained at a high speed of 500 m / s to 1000 m / s. It can be deposited by colliding with the material. The fuel used in high-speed flame spraying may be a hydrocarbon gas fuel such as acetylene, ethylene, propane, or propylene, or a liquid fuel such as kerosene or ethanol. Further, the higher the melting point of the thermal spray material, the higher the temperature of the supersonic combustion flame is preferable. From this viewpoint, it is preferable to use gas fuel.
また、上記のHVOF溶射法を応用した、いわゆるウォームスプレー溶射法と呼ばれている溶射法を採用することもできる。ウォームスプレー溶射法とは、典型的には、上記のHVOF溶射法において、燃焼炎に室温程度の温度の窒素等からなる冷却ガスを混合する等して燃焼炎の温度を低下させた状態で溶射することで、溶射皮膜を形成する手法である。溶射材は、完全に溶融された状態に限定されず、例えば、一部が溶融された状態であったり、融点以下の軟化状態にあったりするものを溶射することができる。このウォームスプレー溶射法によると、例えば、一例として、溶射材料を1000℃~2000℃の超音速燃焼炎のジェットにより溶融および加速させることで、溶射粒子を500m/s~1000m/sという高速度にて基材へ衝突させて堆積させることができる。
HVAF溶射法とは、上記のHVOF溶射法において、支燃ガスとしての酸素に代えて空気を用いるようにした溶射法である。HVAF溶射法によると、HVOF溶射法と比較して溶射温度を低温とすることができる。例えば、一例として、溶射材料を1600℃~2000℃の超音速燃焼炎のジェットにより溶融および加速させることで、溶射粒子を500m/s~1000m/sという高速度にて基材へ衝突させて堆積させることができる。 Also, a so-called warm spray spraying method that applies the above-described HVOF spraying method may be employed. Typically, the warm spray spraying method is the above-described HVOF spraying method in which the temperature of the combustion flame is lowered by mixing the combustion flame with a cooling gas composed of nitrogen or the like at a room temperature. This is a technique for forming a sprayed coating. The thermal spray material is not limited to a completely melted state. For example, a thermal spray material that is partially melted or softened below the melting point can be sprayed. According to this warm spray spraying method, for example, the sprayed material is melted and accelerated by a jet of a supersonic combustion flame at 1000 ° C. to 2000 ° C., so that the sprayed particles can be made at a high speed of 500 m / s to 1000 m / s. And can be deposited by colliding with the substrate.
The HVAF thermal spraying method is a thermal spraying method in which air is used in place of oxygen as a combustion support gas in the HVOF thermal spraying method. According to the HVAF spraying method, the spraying temperature can be lowered as compared with the HVOF spraying method. For example, as an example, a thermal spray material is melted and accelerated by a jet of a supersonic combustion flame at 1600 ° C. to 2000 ° C., so that the thermal spray particles collide with a substrate at a high speed of 500 m / s to 1000 m / s and are deposited. Can be made.
HVAF溶射法とは、上記のHVOF溶射法において、支燃ガスとしての酸素に代えて空気を用いるようにした溶射法である。HVAF溶射法によると、HVOF溶射法と比較して溶射温度を低温とすることができる。例えば、一例として、溶射材料を1600℃~2000℃の超音速燃焼炎のジェットにより溶融および加速させることで、溶射粒子を500m/s~1000m/sという高速度にて基材へ衝突させて堆積させることができる。 Also, a so-called warm spray spraying method that applies the above-described HVOF spraying method may be employed. Typically, the warm spray spraying method is the above-described HVOF spraying method in which the temperature of the combustion flame is lowered by mixing the combustion flame with a cooling gas composed of nitrogen or the like at a room temperature. This is a technique for forming a sprayed coating. The thermal spray material is not limited to a completely melted state. For example, a thermal spray material that is partially melted or softened below the melting point can be sprayed. According to this warm spray spraying method, for example, the sprayed material is melted and accelerated by a jet of a supersonic combustion flame at 1000 ° C. to 2000 ° C., so that the sprayed particles can be made at a high speed of 500 m / s to 1000 m / s. And can be deposited by colliding with the substrate.
The HVAF thermal spraying method is a thermal spraying method in which air is used in place of oxygen as a combustion support gas in the HVOF thermal spraying method. According to the HVAF spraying method, the spraying temperature can be lowered as compared with the HVOF spraying method. For example, as an example, a thermal spray material is melted and accelerated by a jet of a supersonic combustion flame at 1600 ° C. to 2000 ° C., so that the thermal spray particles collide with a substrate at a high speed of 500 m / s to 1000 m / s and are deposited. Can be made.
なお、以上のことからも明らかなように、ここに開示される溶射材料によると、当該溶射材料に含まれるセラミックス粒子を構成するセラミックス材料の融点よりも、より低い温度での溶射が可能とされる。これにより、3次元的に複雑な構造を有するセラミックス粒子の粒成長を抑制しつつ、十分な溶融を実現することで、緻密で微細な組織を有するセラミックスからなる皮膜形成が可能とされる。かかるより低温での溶射温度は、例えば、当該融点よりも、10℃~4000℃程度、例えば50℃~350℃程度低い温度とすることが考慮される。例えば、一例として、ここに開示されるアルミナからなる溶射材料を用いることで、融点が2050℃のアルミナからなる溶射皮膜を、2000℃以下、より限定的には1700℃以下の溶射温度で形成することが可能とされる。また、ここに開示されるイットリア安定化ジルコニアからなる溶射材料を用いることで、融点が2600℃以上のイットリア安定化ジルコニアからなる溶射皮膜を、2550℃以下、より限定的には2300℃以下の溶射温度で形成することが可能とされる。さらに、ここに開示されるムライトからなる溶射材料を用いることで、融点が1915℃のムライトからなる溶射皮膜を、1900℃以下、より限定的には1860℃以下の溶射温度で形成することが可能とされる。
As is clear from the above, according to the thermal spray material disclosed herein, thermal spraying at a temperature lower than the melting point of the ceramic material constituting the ceramic particles contained in the thermal spray material is enabled. The As a result, it is possible to form a film made of ceramics having a dense and fine structure by realizing sufficient melting while suppressing grain growth of ceramic particles having a three-dimensionally complicated structure. It is considered that the spraying temperature at a lower temperature is, for example, about 10 ° C. to 4000 ° C., for example, about 50 ° C. to 350 ° C. lower than the melting point. For example, as an example, by using a thermal spray material made of alumina disclosed herein, a thermal spray coating made of alumina having a melting point of 2050 ° C. is formed at a thermal spray temperature of 2000 ° C. or lower, more specifically 1700 ° C. or lower. It is possible. Further, by using the thermal spray material made of yttria stabilized zirconia disclosed herein, a thermal spray coating made of yttria stabilized zirconia having a melting point of 2600 ° C. or higher can be sprayed to 2550 ° C. or lower, more specifically 2300 ° C. or lower. It is possible to form at temperature. Furthermore, by using the thermal spray material made of mullite disclosed herein, a thermal spray coating made of mullite having a melting point of 1915 ° C. can be formed at a thermal spray temperature of 1900 ° C. or lower, more specifically 1860 ° C. or lower. It is said.
また、ここに開示される溶射材料は、その平均粒子径に因ることなく流動性が高く維持され得ることから、効率よくスムーズに溶射材料を溶射装置に供給することができ、高品質な溶射皮膜を生産性良く形成することができる。したがって、溶射材料の溶射装置への供給方式は特に制限されることはない。例えば、アキシャルフィード方式で行われること、すなわち溶射装置で生じるジェット流の軸と同じ方向に向けて溶射材料の供給が行われることが好ましい。溶射材料が溶射装置内に付着しにくいという観点から、溶射材料をアキシャルフィード方式で溶射装置に供給しすることで、溶射材料をより流動性の良い状態におくことができ、均質な溶射皮膜を効率よく形成することができるために好ましい。
In addition, since the thermal spray material disclosed herein can maintain high fluidity without depending on the average particle diameter, the thermal spray material can be efficiently and smoothly supplied to the thermal spraying device, and high-quality thermal spraying can be performed. A film can be formed with good productivity. Therefore, the method of supplying the spray material to the spraying device is not particularly limited. For example, it is preferable to perform the axial feed method, that is, to supply the thermal spray material in the same direction as the axis of the jet flow generated in the thermal spraying apparatus. From the viewpoint that the thermal spray material is less likely to adhere to the thermal spraying device, the thermal spray material can be kept in a more fluid state by supplying the thermal spraying material to the thermal spraying device by an axial feed method, and a uniform thermal spray coating can be obtained. It is preferable because it can be formed efficiently.
なお、溶射距離は、溶射方法および溶射装置により適宜設定することができる。おおよその目安として、ノズル先端から基材までの距離が30mm以上200mm以下程度とすることが好ましい。溶射距離が近すぎると、溶射熱源が基材に近接するため基材が変質したり変形を生じたりするおそれがあるために好ましくない。溶射距離が遠すぎると、溶融粒子の速度が低減されることと冷却が進むことから、十分な付着性が得られなくなる可能性があるために好ましくない。溶射距離は、例えば、上記の範囲であると、十分に加熱された溶射粒子が当該温度を保ったまま基材に適切な速度で到達し得るため、織密で付着性の良い溶射皮膜を得ることができる。
In addition, the spraying distance can be appropriately set depending on the spraying method and the spraying apparatus. As a rough guide, the distance from the nozzle tip to the substrate is preferably about 30 mm or more and 200 mm or less. If the spraying distance is too short, the thermal spray heat source is close to the base material, and therefore the base material may be altered or deformed, which is not preferable. If the spraying distance is too long, the speed of the molten particles is reduced and the cooling proceeds, so that sufficient adhesion may not be obtained, which is not preferable. When the spraying distance is within the above range, for example, the sufficiently heated sprayed particles can reach the substrate at an appropriate speed while maintaining the temperature, so that a sprayed coating having a dense and good adhesion is obtained. be able to.
なお、被溶射材である基材についても特に制限はなく、各種の材料からなるものを用いることができる。かかる材料としては、例えば、各種の金属または合金等が挙げられる。具体的には、例えば、アルミニウム、アルミニウム合金、鉄、鉄鋼、銅、銅合金、ニッケル、ニッケル合金、金、銀、ビスマス、マンガン、亜鉛、亜鉛合金等が例示される。なかでも、汎用されている金属材料のうち比較的熱膨張係数の大きい、各種SUS材(いわゆるステンレス銅であり得る。)等に代表される鉄鋼、インコネル等に代表される耐熱合金、インバー,コバール等に代表される低膨張合金、ハステロイ等に代表される耐食合金、軽量構造材等として有用な1000シリーズ~7000シリーズアルミニウム合金等に代表されるアルミニウム合金等からなる基材は、ここに開示される方法により好適に緻密で密着性の良い溶射皮膜を形成でき、本発明の利点が明瞭となり得る点で好ましい。
In addition, there is no restriction | limiting in particular also about the base material which is a sprayed material, What consists of various materials can be used. Examples of such materials include various metals or alloys. Specifically, for example, aluminum, aluminum alloy, iron, steel, copper, copper alloy, nickel, nickel alloy, gold, silver, bismuth, manganese, zinc, zinc alloy and the like are exemplified. Among them, steels represented by various SUS materials (which may be so-called stainless copper), heat resistant alloys represented by Inconel, Invar, Kovar, etc., which have a relatively large coefficient of thermal expansion among metal materials that are widely used. A base material made of a low expansion alloy represented by, etc., a corrosion resistant alloy represented by Hastelloy, etc., an aluminum alloy represented by 1000 series to 7000 series aluminum alloys useful as a lightweight structural material, etc. is disclosed herein. This method is preferable in that a finely sprayed coating having good adhesion can be formed suitably, and the advantages of the present invention can be clarified.
以下、本発明に関する実施例を説明するが、本発明を以下の実施例に示すものに限定することを意図したものではない。
Hereinafter, examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in the following examples.
下記の表1に示す8種類の溶射材料を用意した。すなわち、サンプル1~6の溶射材料は、いずれも平均粒子径が24μmのアルミナ粒子により構成されている。これらのうち、サンプル1の溶射材料は、溶融-粉砕法により製造され、アルミナ(Al2O3)からなる一次粒子の平均粒子径が24μmである。そしてサンプル2~6の溶射材料は、それぞれ表に示す平均粒子径を有するアルミナからなる一次粒子が、造粒および焼結されることにより、上記の平均粒子径のアルミナ二次粒子を構成している。サンプル7および8の溶射材料は、それぞれイットリア(Y2O3)および8%イットリア安定化ジルコニア(8% Yttria-Stabilized Zirconia:8%YSZ)からなる、平均粒子径が24μmの粒子を含んでいる。これらの粒子も、それぞれ表に示す平均粒子径を有する一次粒子が造粒および焼結されることにより、上記の平均粒子径の二次粒子を構成している。
Eight types of thermal spray materials shown in Table 1 below were prepared. That is, the thermal spray materials of Samples 1 to 6 are all composed of alumina particles having an average particle diameter of 24 μm. Among these, the thermal spray material of Sample 1 is manufactured by the melt-pulverization method, and the average particle diameter of primary particles made of alumina (Al 2 O 3 ) is 24 μm. The thermal spray materials of Samples 2 to 6 are composed of alumina secondary particles having the above average particle diameter by forming and sintering primary particles made of alumina each having the average particle diameter shown in the table. Yes. The thermal spray materials of Samples 7 and 8 contain particles having an average particle size of 24 μm, each composed of yttria (Y 2 O 3 ) and 8% Yttria-Stabilized Zirconia (8% YSZ). . These particles also form secondary particles having the above average particle diameter by granulating and sintering primary particles having the average particle diameter shown in the table.
なお、溶融-粉砕法による溶射材料の調製は以下の手順で行った。すなわち、まず、目的のセラミック(この場合は、Al2O3)が得られるよう原料粉末を配合し、かかる原料粉末を加熱して溶融させた後、冷却して固化物(インゴッド)を用意する。そしてかかる固化物を機械的手段により粉砕し、必要に応じて分級を行うことで、溶射材料とした。この溶融-粉砕法により得られたサンプル1の溶射材料に含まれるアルミナ粒子は、比較的緻密かつ強固であって、粉砕粉末特有のエッジを有した角状あるいは塊状の形状を有するものであった。
The sprayed material was prepared by the following procedure by the melt-pulverization method. That is, first, raw material powder is blended so as to obtain a target ceramic (in this case, Al 2 O 3 ), the raw material powder is heated and melted, and then cooled to prepare a solidified product (ingot). . The solidified product was pulverized by mechanical means and classified as necessary to obtain a thermal spray material. The alumina particles contained in the thermal spray material of Sample 1 obtained by this melt-pulverization method were relatively dense and strong, and had a square or lump shape with an edge characteristic of the pulverized powder. .
また、造粒-焼結法による溶射材料の調製は以下の手順で行った。すなわち、まず、所定の平均粒子径のセラミック(一次粒子,この場合はAl2O3,Y2O3,8%YSZ等の超微粒子)の表面処理を行い、バインダー(PVA:ポリビニルアルコール)と共に溶媒(水およびアルコールの混合溶液等)に十分に混合して分散させ、スラリーを調製する。次いで、このスラリーを、噴霧造粒機および乾燥焼結炉等を用いて液滴状に造粒し、乾燥および焼結させることでセラミックス粒子(二次粒子)を得る。そして、かかるセラミックス粒子を必要に応じて分級することで溶射材料とした。
この造粒-焼結法により得られたサンプル2~8の溶射材料に含まれるセラミックス粒子は、例えば、図1および図2に示されるように、ごく微細な一次粒子が互いに結合して、略球形状の二次粒子を構成している。なお、図1は、サンプル6の溶射材料の後述の走査型電子顕微鏡で観察して得られた像である。また、図2は、図1中の一つのセラミックス粒子を高倍率で観察して得られた像である。なお、ごく微細な一次粒子を詳細に観察すると、これらは特定の結晶面が発達した角柱状あるいは塊状の形状を有するものであった。 The sprayed material was prepared by the granulation-sintering method according to the following procedure. That is, first, a ceramic (primary particles, in this case, ultrafine particles such as Al 2 O 3 , Y 2 O 3 , 8% YSZ) having a predetermined average particle diameter is subjected to surface treatment, together with a binder (PVA: polyvinyl alcohol). A slurry is prepared by thoroughly mixing and dispersing in a solvent (such as a mixed solution of water and alcohol). Next, the slurry is granulated into droplets using a spray granulator and a dry sintering furnace, and dried and sintered to obtain ceramic particles (secondary particles). And it was set as the thermal spray material by classifying this ceramic particle as needed.
The ceramic particles contained in the thermal spray materials of Samples 2 to 8 obtained by the granulation-sintering method are substantially the same as shown in FIGS. 1 and 2, in which very fine primary particles are bonded to each other. It constitutes spherical secondary particles. FIG. 1 is an image obtained by observing the thermal spray material of Sample 6 with a scanning electron microscope described later. FIG. 2 is an image obtained by observing one ceramic particle in FIG. 1 at a high magnification. In addition, when very fine primary particles were observed in detail, they had a prismatic or massive shape with a specific crystal plane developed.
この造粒-焼結法により得られたサンプル2~8の溶射材料に含まれるセラミックス粒子は、例えば、図1および図2に示されるように、ごく微細な一次粒子が互いに結合して、略球形状の二次粒子を構成している。なお、図1は、サンプル6の溶射材料の後述の走査型電子顕微鏡で観察して得られた像である。また、図2は、図1中の一つのセラミックス粒子を高倍率で観察して得られた像である。なお、ごく微細な一次粒子を詳細に観察すると、これらは特定の結晶面が発達した角柱状あるいは塊状の形状を有するものであった。 The sprayed material was prepared by the granulation-sintering method according to the following procedure. That is, first, a ceramic (primary particles, in this case, ultrafine particles such as Al 2 O 3 , Y 2 O 3 , 8% YSZ) having a predetermined average particle diameter is subjected to surface treatment, together with a binder (PVA: polyvinyl alcohol). A slurry is prepared by thoroughly mixing and dispersing in a solvent (such as a mixed solution of water and alcohol). Next, the slurry is granulated into droplets using a spray granulator and a dry sintering furnace, and dried and sintered to obtain ceramic particles (secondary particles). And it was set as the thermal spray material by classifying this ceramic particle as needed.
The ceramic particles contained in the thermal spray materials of Samples 2 to 8 obtained by the granulation-sintering method are substantially the same as shown in FIGS. 1 and 2, in which very fine primary particles are bonded to each other. It constitutes spherical secondary particles. FIG. 1 is an image obtained by observing the thermal spray material of Sample 6 with a scanning electron microscope described later. FIG. 2 is an image obtained by observing one ceramic particle in FIG. 1 at a high magnification. In addition, when very fine primary particles were observed in detail, they had a prismatic or massive shape with a specific crystal plane developed.
サンプル1~8の溶射材料の形態および流動性を評価し、その結果を表1に併せて示した。なお、表1に示した物性値の測定方法については以下に説明する。
[セラミックス粒子の平均粒子径]
セラミックス粒子の平均粒子径は、サンプル1~8の溶射材料をレーザ回折/散乱式粒度測定器(株式会社堀場製作所製,LA-300)に供して測定した、体積基準の粒度分布に基づくD50粒径である。セラミックス粒子の平均粒子径の測定結果を、表1の「平均粒子径」の欄に示した。 The form and flowability of the thermal spray materials of Samples 1 to 8 were evaluated, and the results are also shown in Table 1. In addition, the measuring method of the physical property value shown in Table 1 is demonstrated below.
[Average particle size of ceramic particles]
The average particle diameter of the ceramic particles, samples 1-8 a laser diffraction / scattering type particle size measuring instrument thermal spray material (Co. Horiba, LA-300) was measured and subjected to, D 50 based on volume-based particle size distribution The particle size. The measurement result of the average particle diameter of the ceramic particles is shown in the column of “Average particle diameter” in Table 1.
[セラミックス粒子の平均粒子径]
セラミックス粒子の平均粒子径は、サンプル1~8の溶射材料をレーザ回折/散乱式粒度測定器(株式会社堀場製作所製,LA-300)に供して測定した、体積基準の粒度分布に基づくD50粒径である。セラミックス粒子の平均粒子径の測定結果を、表1の「平均粒子径」の欄に示した。 The form and flowability of the thermal spray materials of Samples 1 to 8 were evaluated, and the results are also shown in Table 1. In addition, the measuring method of the physical property value shown in Table 1 is demonstrated below.
[Average particle size of ceramic particles]
The average particle diameter of the ceramic particles, samples 1-8 a laser diffraction / scattering type particle size measuring instrument thermal spray material (Co. Horiba, LA-300) was measured and subjected to, D 50 based on volume-based particle size distribution The particle size. The measurement result of the average particle diameter of the ceramic particles is shown in the column of “Average particle diameter” in Table 1.
[比表面積]
セラミックス粒子の比表面積は、流動式比表面積自動測定装置(島津製作所製、フローソーブII 2300)を用い、吸着ガスとして窒素ガスを使用したBET法に基づき測定した。具体的には、試料としてのセラミックス粒子を試料管に投入したのち、当該試料を冷却し、試料管内に窒素ガスを導入し、定容量法ガス吸着法による吸脱着等温線を作製する。そしてかかる吸脱着等温線における、一層目の単分子層吸着から多層吸着に移行する過程をBET法に基づき解析することにより単分子層吸着量を算出し、さらに窒素ガス分子一個の占める断面積を積算することで、比表面積を得る。このようにして求めたセラミックス粒子の比表面積の測定結果を、表1の「比表面積」の欄に示した。 [Specific surface area]
The specific surface area of the ceramic particles was measured based on the BET method using nitrogen gas as an adsorbed gas, using a flow type specific surface area automatic measuring device (manufactured by Shimadzu Corporation, Flowsorb II 2300). Specifically, after putting ceramic particles as a sample into a sample tube, the sample is cooled, nitrogen gas is introduced into the sample tube, and an adsorption / desorption isotherm by a constant volume method gas adsorption method is prepared. And in this adsorption / desorption isotherm, the process of transition from monolayer adsorption of the first layer to multilayer adsorption is analyzed based on the BET method to calculate the amount of monolayer adsorption, and the cross-sectional area occupied by one nitrogen gas molecule is calculated. The specific surface area is obtained by integrating. The measurement results of the specific surface area of the ceramic particles thus obtained are shown in the column “specific surface area” of Table 1.
セラミックス粒子の比表面積は、流動式比表面積自動測定装置(島津製作所製、フローソーブII 2300)を用い、吸着ガスとして窒素ガスを使用したBET法に基づき測定した。具体的には、試料としてのセラミックス粒子を試料管に投入したのち、当該試料を冷却し、試料管内に窒素ガスを導入し、定容量法ガス吸着法による吸脱着等温線を作製する。そしてかかる吸脱着等温線における、一層目の単分子層吸着から多層吸着に移行する過程をBET法に基づき解析することにより単分子層吸着量を算出し、さらに窒素ガス分子一個の占める断面積を積算することで、比表面積を得る。このようにして求めたセラミックス粒子の比表面積の測定結果を、表1の「比表面積」の欄に示した。 [Specific surface area]
The specific surface area of the ceramic particles was measured based on the BET method using nitrogen gas as an adsorbed gas, using a flow type specific surface area automatic measuring device (manufactured by Shimadzu Corporation, Flowsorb II 2300). Specifically, after putting ceramic particles as a sample into a sample tube, the sample is cooled, nitrogen gas is introduced into the sample tube, and an adsorption / desorption isotherm by a constant volume method gas adsorption method is prepared. And in this adsorption / desorption isotherm, the process of transition from monolayer adsorption of the first layer to multilayer adsorption is analyzed based on the BET method to calculate the amount of monolayer adsorption, and the cross-sectional area occupied by one nitrogen gas molecule is calculated. The specific surface area is obtained by integrating. The measurement results of the specific surface area of the ceramic particles thus obtained are shown in the column “specific surface area” of Table 1.
[一次粒子の平均粒子径]
一次粒子の平均粒子径は、サンプル1~8の溶射材料の比表面積をもとに算出した値を採用した。すなわち、一次粒子に関する「平均粒子径」は、上記で測定したセラミックス粒子の比表面積をSm、密度をρとして、次式に基づき求めた値である。なお、各セラミックス材料の密度としては、Al2O3:3.98g/ml,Y2O3:5.03g/ml,8%YSZ:5.58g/mlの値を採用した。このようにして求めたセラミックス粒子の一次粒子の平均粒子径の値を、表1の「平均一次粒子径」の欄に示した。
Dave=6/(ρSm) [Average particle size of primary particles]
As the average particle diameter of the primary particles, a value calculated based on the specific surface area of the thermal spray material of Samples 1 to 8 was adopted. That is, the “average particle diameter” regarding the primary particles is a value obtained based on the following equation, where S m is the specific surface area of the ceramic particles measured above, and ρ is the density. As the density of each ceramic material, values of Al 2 O 3 : 3.98 g / ml, Y 2 O 3 : 5.03 g / ml, 8% YSZ: 5.58 g / ml were adopted. The value of the average particle size of the primary particles of the ceramic particles thus obtained is shown in the column “Average primary particle size” in Table 1.
D ave = 6 / (ρS m )
一次粒子の平均粒子径は、サンプル1~8の溶射材料の比表面積をもとに算出した値を採用した。すなわち、一次粒子に関する「平均粒子径」は、上記で測定したセラミックス粒子の比表面積をSm、密度をρとして、次式に基づき求めた値である。なお、各セラミックス材料の密度としては、Al2O3:3.98g/ml,Y2O3:5.03g/ml,8%YSZ:5.58g/mlの値を採用した。このようにして求めたセラミックス粒子の一次粒子の平均粒子径の値を、表1の「平均一次粒子径」の欄に示した。
Dave=6/(ρSm) [Average particle size of primary particles]
As the average particle diameter of the primary particles, a value calculated based on the specific surface area of the thermal spray material of Samples 1 to 8 was adopted. That is, the “average particle diameter” regarding the primary particles is a value obtained based on the following equation, where S m is the specific surface area of the ceramic particles measured above, and ρ is the density. As the density of each ceramic material, values of Al 2 O 3 : 3.98 g / ml, Y 2 O 3 : 5.03 g / ml, 8% YSZ: 5.58 g / ml were adopted. The value of the average particle size of the primary particles of the ceramic particles thus obtained is shown in the column “Average primary particle size” in Table 1.
D ave = 6 / (ρS m )
[平均真円度]
セラミックス粒子の平均真円度は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像(倍率1000~2000倍)について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定した真円度の算術平均値を算出することで求めた。なお、真円度は、SEM像のコントラストからセラミックス粒子の輪郭をトレースすることで、かかるセラミックス粒子の周囲長および面積(平面視)を算出し、これらの値から、真円度=(周囲長2)÷(4×π×面積)の関係に基づき求めた値である。セラミックス粒子の平均真円度の測定結果を、表1の「平均真円度」の欄に示した。 [Average roundness]
The average roundness of the ceramic particles is a planar view image (magnification) obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). 1000-2000 times) was calculated by calculating the arithmetic average value of roundness measured for 100 or more ceramic particles using image analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.). The roundness is calculated by tracing the contour of the ceramic particle from the contrast of the SEM image, thereby calculating the perimeter and area (plan view) of the ceramic particle. From these values, the roundness = (perimeter length) 2 ) / (4 × π × area). The measurement result of the average roundness of the ceramic particles is shown in the column “average roundness” of Table 1.
セラミックス粒子の平均真円度は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像(倍率1000~2000倍)について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定した真円度の算術平均値を算出することで求めた。なお、真円度は、SEM像のコントラストからセラミックス粒子の輪郭をトレースすることで、かかるセラミックス粒子の周囲長および面積(平面視)を算出し、これらの値から、真円度=(周囲長2)÷(4×π×面積)の関係に基づき求めた値である。セラミックス粒子の平均真円度の測定結果を、表1の「平均真円度」の欄に示した。 [Average roundness]
The average roundness of the ceramic particles is a planar view image (magnification) obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). 1000-2000 times) was calculated by calculating the arithmetic average value of roundness measured for 100 or more ceramic particles using image analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.). The roundness is calculated by tracing the contour of the ceramic particle from the contrast of the SEM image, thereby calculating the perimeter and area (plan view) of the ceramic particle. From these values, the roundness = (perimeter length) 2 ) / (4 × π × area). The measurement result of the average roundness of the ceramic particles is shown in the column “average roundness” of Table 1.
[平均アスペクト比]
セラミックス粒子の平均アスペクト比は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像(倍率1000~2000倍)について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定したアスペクト比の算術平均値を算出することで求めた。なお、アスペクト比は、SEM像のコントラストからセラミックス粒子の輪郭を特定し、その相当楕円(同面積でかつ一次および二次モーメントが等しい楕円)の長軸の長さを長径a、短軸の長さを短径bとし、これらの値からa/bで定義されるアスペクト比を求めた値である。セラミックス粒子の平均アスペクト比の測定結果を、表1の「平均アスペクト比」の欄に示した。 [Average aspect ratio]
The average aspect ratio of the ceramic particles is a planar view image (magnification 1000) obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). ˜2000 times) was calculated by calculating the arithmetic average of the aspect ratios measured for 100 or more ceramic particles using image analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.). Note that the aspect ratio specifies the contour of the ceramic particle from the contrast of the SEM image, and the major axis length of the corresponding ellipse (the ellipse having the same area and the same primary and secondary moments) is the major axis a and the minor axis length. This is a value obtained by determining the aspect ratio defined by a / b from these values, where the minor axis is b. The measurement result of the average aspect ratio of the ceramic particles is shown in the column of “Average aspect ratio” in Table 1.
セラミックス粒子の平均アスペクト比は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像(倍率1000~2000倍)について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定したアスペクト比の算術平均値を算出することで求めた。なお、アスペクト比は、SEM像のコントラストからセラミックス粒子の輪郭を特定し、その相当楕円(同面積でかつ一次および二次モーメントが等しい楕円)の長軸の長さを長径a、短軸の長さを短径bとし、これらの値からa/bで定義されるアスペクト比を求めた値である。セラミックス粒子の平均アスペクト比の測定結果を、表1の「平均アスペクト比」の欄に示した。 [Average aspect ratio]
The average aspect ratio of the ceramic particles is a planar view image (magnification 1000) obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). ˜2000 times) was calculated by calculating the arithmetic average of the aspect ratios measured for 100 or more ceramic particles using image analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.). Note that the aspect ratio specifies the contour of the ceramic particle from the contrast of the SEM image, and the major axis length of the corresponding ellipse (the ellipse having the same area and the same primary and secondary moments) is the major axis a and the minor axis length. This is a value obtained by determining the aspect ratio defined by a / b from these values, where the minor axis is b. The measurement result of the average aspect ratio of the ceramic particles is shown in the column of “Average aspect ratio” in Table 1.
[平均フラクタル次元]
セラミックス粒子の平均フラクタル次元は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定したフラクタル次元の算術平均値を算出することで求めた。SEMでの解析条件は、倍率:2000倍、ビット深さ:8、走査速度:80/100sとした。なお、フラクタル次元の測定に用いるSEM像は、セラミックス粒子の周囲長が30ピクセル以上(好ましくは1280ピクセル以上。本実施形態では、960×1280ピクセルとした。)となる解像度を実現するものを用意した。そして、フラクタル次元の測定では、かかるSEM像のコントラストからセラミックス粒子の輪郭をトレースすることで、セラミックス粒子の周囲長および面積(平面視)を算出し、これらの値から、真円度=(周囲長2)÷(4×π×面積)の関係に基づきフラクタル次元を求めた。セラミックス粒子の平均真円度の測定結果を、表1の「平均FD」の欄に示した。 [Average fractal dimension]
The average fractal dimension of the ceramic particles is the image of a planar view image obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). Using an analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.), the arithmetic average value of the fractal dimension measured for 100 or more ceramic particles was calculated. SEM analysis conditions were as follows: magnification: 2000 times, bit depth: 8, scanning speed: 80/100 s. In addition, the SEM image used for the measurement of the fractal dimension is prepared to realize a resolution in which the peripheral length of the ceramic particles is 30 pixels or more (preferably 1280 pixels or more. In this embodiment, 960 × 1280 pixels). did. In the measurement of the fractal dimension, by tracing the contour of the ceramic particle from the contrast of the SEM image, the circumference and area (plan view) of the ceramic particle are calculated, and from these values, the roundness = (ambient The fractal dimension was determined based on the relationship of length 2 ) ÷ (4 × π × area). The measurement result of the average roundness of the ceramic particles is shown in the column of “Average FD” in Table 1.
セラミックス粒子の平均フラクタル次元は、サンプル1~8の溶射材料を走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た平面視像について、画像解析ソフト(株式会社日本ローバー製、Image-Pro Plus)を用い、100以上のセラミックス粒子について測定したフラクタル次元の算術平均値を算出することで求めた。SEMでの解析条件は、倍率:2000倍、ビット深さ:8、走査速度:80/100sとした。なお、フラクタル次元の測定に用いるSEM像は、セラミックス粒子の周囲長が30ピクセル以上(好ましくは1280ピクセル以上。本実施形態では、960×1280ピクセルとした。)となる解像度を実現するものを用意した。そして、フラクタル次元の測定では、かかるSEM像のコントラストからセラミックス粒子の輪郭をトレースすることで、セラミックス粒子の周囲長および面積(平面視)を算出し、これらの値から、真円度=(周囲長2)÷(4×π×面積)の関係に基づきフラクタル次元を求めた。セラミックス粒子の平均真円度の測定結果を、表1の「平均FD」の欄に示した。 [Average fractal dimension]
The average fractal dimension of the ceramic particles is the image of a planar view image obtained by observing the sprayed materials of Samples 1 to 8 with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N). Using an analysis software (Image-Pro Plus, manufactured by Nippon Rover Co., Ltd.), the arithmetic average value of the fractal dimension measured for 100 or more ceramic particles was calculated. SEM analysis conditions were as follows: magnification: 2000 times, bit depth: 8, scanning speed: 80/100 s. In addition, the SEM image used for the measurement of the fractal dimension is prepared to realize a resolution in which the peripheral length of the ceramic particles is 30 pixels or more (preferably 1280 pixels or more. In this embodiment, 960 × 1280 pixels). did. In the measurement of the fractal dimension, by tracing the contour of the ceramic particle from the contrast of the SEM image, the circumference and area (plan view) of the ceramic particle are calculated, and from these values, the roundness = (ambient The fractal dimension was determined based on the relationship of length 2 ) ÷ (4 × π × area). The measurement result of the average roundness of the ceramic particles is shown in the column of “Average FD” in Table 1.
[安息角]
溶射材料の安息角は、サンプル1~8の溶射材料をA.B.D.粉体特性測定器(筒井理科器械株式会社製、ABD-72形)に供することで得た値である。溶射材料の安息角の測定結果を、表1の「安息角」の欄に示した。
[フローファンクション]
なお、参考のために、サンプル6の溶射材料を粉体流動性分析装置(Freeman Tchnology社製、パウダーレオメーターFT4)により測定した。その結果、サンプル6の溶射材料のフローファンクションは9.2であった。 [Angle of repose]
The angle of repose of the thermal spray material is the same as that of the thermal spray material of Samples 1-8. B. D. This is a value obtained by applying to a powder property measuring instrument (ABD-72, manufactured by Tsutsui Science Instruments Co., Ltd.). The measurement results of the repose angle of the thermal spray material are shown in the column “Repose angle” in Table 1.
[Flow function]
For reference, the thermal spray material of Sample 6 was measured with a powder fluidity analyzer (Powder Rheometer FT4, manufactured by Freeman Tchnology). As a result, the flow function of the thermal spray material of Sample 6 was 9.2.
溶射材料の安息角は、サンプル1~8の溶射材料をA.B.D.粉体特性測定器(筒井理科器械株式会社製、ABD-72形)に供することで得た値である。溶射材料の安息角の測定結果を、表1の「安息角」の欄に示した。
[フローファンクション]
なお、参考のために、サンプル6の溶射材料を粉体流動性分析装置(Freeman Tchnology社製、パウダーレオメーターFT4)により測定した。その結果、サンプル6の溶射材料のフローファンクションは9.2であった。 [Angle of repose]
The angle of repose of the thermal spray material is the same as that of the thermal spray material of Samples 1-8. B. D. This is a value obtained by applying to a powder property measuring instrument (ABD-72, manufactured by Tsutsui Science Instruments Co., Ltd.). The measurement results of the repose angle of the thermal spray material are shown in the column “Repose angle” in Table 1.
[Flow function]
For reference, the thermal spray material of Sample 6 was measured with a powder fluidity analyzer (Powder Rheometer FT4, manufactured by Freeman Tchnology). As a result, the flow function of the thermal spray material of Sample 6 was 9.2.
[溶射方法]
上記で用意した溶射材料を、低温プロセスであるHVOF溶射法により溶射することにより、溶射材料による溶射皮膜の成膜性を評価した。溶射条件は、以下の通りとした。
すなわち、まず、基材にはSS400鋼板(70mm×50mm×2.3mm)を用意し、表面に#40のアルミナグリッドを用いたブラスト処理を施すことにより粗面化加工して用いた。HVOF溶射には、市販の高速フレーム溶射機(Praxair/TAFA社製、JP-5000)を用いた。この溶射機はフレーム温度の上限が約2000℃と、溶射材料に用いられたセラミックスの融点よりも大幅に低い温度である。溶射材料は、粉末供給機(テクノサーブ社製、AM-30)を用い、乾粉状態で、約15g/分の供給量で溶射機のバーナー室に供給した。なお、溶射機には、燃料ガスとしてアセチレンガスを75L/min、助燃剤としての酸素ガスを230L/minの流量で供給した。これにより、溶射機のノズルから溶射材料に応じて1500℃~2500℃程度の超音速ジェットを噴射させ、バーナー室に供給した溶射材料をかかるジェットに載せて溶融、飛行させ、基材に吹き付けることで、基材上に皮膜を形成した。なお、溶射ガンの移動速度は100m/min、溶射距離は90mmとした。また、溶射距離がおよそ30mm~90mmの範囲の飛行粒子の表面温度を、溶射飛行粒子解析機(DPV2000)を用いて測定したところ、サンプル1~8の溶射材料は、表1に示すように、それぞれ1500℃~2500℃に加熱されていることが確認できた。 [Spraying method]
The spraying material prepared above was sprayed by the HVOF spraying method, which is a low-temperature process, to evaluate the film formability of the sprayed coating by the spraying material. The thermal spraying conditions were as follows.
That is, first, an SS400 steel plate (70 mm × 50 mm × 2.3 mm) was prepared as a base material, and the surface was roughened by performing a blasting process using a # 40 alumina grid. A commercially available high-speed flame sprayer (Praxair / TAFA, JP-5000) was used for HVOF spraying. In this thermal spraying machine, the upper limit of the flame temperature is about 2000 ° C., which is much lower than the melting point of the ceramic used for the thermal spray material. The thermal spray material was supplied to the burner chamber of the thermal sprayer at a supply rate of about 15 g / min in a dry powder state using a powder feeder (TechnoServ, AM-30). The thermal sprayer was supplied with acetylene gas as a fuel gas at a flow rate of 75 L / min and oxygen gas as a combustion aid at a flow rate of 230 L / min. As a result, a supersonic jet of about 1500 ° C. to 2500 ° C. is ejected from the nozzle of the thermal sprayer in accordance with the thermal spray material, and the thermal spray material supplied to the burner chamber is placed on the jet to be melted and flighted and sprayed onto the substrate. A film was formed on the substrate. The moving speed of the spray gun was 100 m / min, and the spray distance was 90 mm. Further, when the surface temperature of the flying particles having a spraying distance of about 30 mm to 90 mm was measured using a spraying flying particle analyzer (DPV2000), the spraying materials of Samples 1 to 8 are as shown in Table 1. It was confirmed that each was heated to 1500 ° C. to 2500 ° C.
上記で用意した溶射材料を、低温プロセスであるHVOF溶射法により溶射することにより、溶射材料による溶射皮膜の成膜性を評価した。溶射条件は、以下の通りとした。
すなわち、まず、基材にはSS400鋼板(70mm×50mm×2.3mm)を用意し、表面に#40のアルミナグリッドを用いたブラスト処理を施すことにより粗面化加工して用いた。HVOF溶射には、市販の高速フレーム溶射機(Praxair/TAFA社製、JP-5000)を用いた。この溶射機はフレーム温度の上限が約2000℃と、溶射材料に用いられたセラミックスの融点よりも大幅に低い温度である。溶射材料は、粉末供給機(テクノサーブ社製、AM-30)を用い、乾粉状態で、約15g/分の供給量で溶射機のバーナー室に供給した。なお、溶射機には、燃料ガスとしてアセチレンガスを75L/min、助燃剤としての酸素ガスを230L/minの流量で供給した。これにより、溶射機のノズルから溶射材料に応じて1500℃~2500℃程度の超音速ジェットを噴射させ、バーナー室に供給した溶射材料をかかるジェットに載せて溶融、飛行させ、基材に吹き付けることで、基材上に皮膜を形成した。なお、溶射ガンの移動速度は100m/min、溶射距離は90mmとした。また、溶射距離がおよそ30mm~90mmの範囲の飛行粒子の表面温度を、溶射飛行粒子解析機(DPV2000)を用いて測定したところ、サンプル1~8の溶射材料は、表1に示すように、それぞれ1500℃~2500℃に加熱されていることが確認できた。 [Spraying method]
The spraying material prepared above was sprayed by the HVOF spraying method, which is a low-temperature process, to evaluate the film formability of the sprayed coating by the spraying material. The thermal spraying conditions were as follows.
That is, first, an SS400 steel plate (70 mm × 50 mm × 2.3 mm) was prepared as a base material, and the surface was roughened by performing a blasting process using a # 40 alumina grid. A commercially available high-speed flame sprayer (Praxair / TAFA, JP-5000) was used for HVOF spraying. In this thermal spraying machine, the upper limit of the flame temperature is about 2000 ° C., which is much lower than the melting point of the ceramic used for the thermal spray material. The thermal spray material was supplied to the burner chamber of the thermal sprayer at a supply rate of about 15 g / min in a dry powder state using a powder feeder (TechnoServ, AM-30). The thermal sprayer was supplied with acetylene gas as a fuel gas at a flow rate of 75 L / min and oxygen gas as a combustion aid at a flow rate of 230 L / min. As a result, a supersonic jet of about 1500 ° C. to 2500 ° C. is ejected from the nozzle of the thermal sprayer in accordance with the thermal spray material, and the thermal spray material supplied to the burner chamber is placed on the jet to be melted and flighted and sprayed onto the substrate. A film was formed on the substrate. The moving speed of the spray gun was 100 m / min, and the spray distance was 90 mm. Further, when the surface temperature of the flying particles having a spraying distance of about 30 mm to 90 mm was measured using a spraying flying particle analyzer (DPV2000), the spraying materials of Samples 1 to 8 are as shown in Table 1. It was confirmed that each was heated to 1500 ° C. to 2500 ° C.
[成膜性]
サンプル1~8の溶射材料を用いて溶射を行った際の成膜性について評価した結果を、表1の「成膜性」の欄に示した。成膜性の「成膜可否」の欄には、上記の溶射条件による成膜が可能であった場合に「可」を、成膜が不可能であった場合に「否」として示した。また、成膜性の「成膜速度」の欄には、上記の溶射条件による成膜において、成膜速度が5μm/passの良好な成膜が可能であった場合に「○」を、かかる成膜速度での成膜が不可能であった場合に「×」を、成膜自体ができなかった場合に「-」を示した。なお、成膜速度を表す単位(μm/pass)は、溶射装置(溶射ガン)が、溶射装置または溶射対象(基材)の運行方向に沿って行う1回の溶射操作(1pass)に製膜し得る溶射皮膜の厚み(μm)を示している。 [Film formability]
The results of evaluating the film formability when spraying using the thermal spray materials of Samples 1 to 8 are shown in the “film formability” column of Table 1. In the “deposition possibility” column of the film formability, “permitted” is shown when film formation under the above spraying conditions is possible, and “no” when film formation is impossible. In the column of “film formation speed” of the film formability, “○” is given when the film formation speed is 5 μm / pass in the film formation under the above-mentioned spraying conditions. When film formation at the film formation speed was impossible, “x” was shown, and when film formation itself was not possible, “-” was shown. In addition, the unit (μm / pass) representing the film formation rate is formed by a single spraying operation (1 pass) performed by the spraying device (spraying gun) along the operating direction of the spraying device or the object to be sprayed (base material). The thickness (μm) of the sprayed coating that can be obtained is shown.
サンプル1~8の溶射材料を用いて溶射を行った際の成膜性について評価した結果を、表1の「成膜性」の欄に示した。成膜性の「成膜可否」の欄には、上記の溶射条件による成膜が可能であった場合に「可」を、成膜が不可能であった場合に「否」として示した。また、成膜性の「成膜速度」の欄には、上記の溶射条件による成膜において、成膜速度が5μm/passの良好な成膜が可能であった場合に「○」を、かかる成膜速度での成膜が不可能であった場合に「×」を、成膜自体ができなかった場合に「-」を示した。なお、成膜速度を表す単位(μm/pass)は、溶射装置(溶射ガン)が、溶射装置または溶射対象(基材)の運行方向に沿って行う1回の溶射操作(1pass)に製膜し得る溶射皮膜の厚み(μm)を示している。 [Film formability]
The results of evaluating the film formability when spraying using the thermal spray materials of Samples 1 to 8 are shown in the “film formability” column of Table 1. In the “deposition possibility” column of the film formability, “permitted” is shown when film formation under the above spraying conditions is possible, and “no” when film formation is impossible. In the column of “film formation speed” of the film formability, “○” is given when the film formation speed is 5 μm / pass in the film formation under the above-mentioned spraying conditions. When film formation at the film formation speed was impossible, “x” was shown, and when film formation itself was not possible, “-” was shown. In addition, the unit (μm / pass) representing the film formation rate is formed by a single spraying operation (1 pass) performed by the spraying device (spraying gun) along the operating direction of the spraying device or the object to be sprayed (base material). The thickness (μm) of the sprayed coating that can be obtained is shown.
[溶射皮膜の粒子径]
また、サンプル1~8の溶射材料により形成された溶射皮膜を構成する粒子の平均粒子径を測定した結果を、表1の溶射皮膜の「平均粒子径」の欄に示した。
ここで、溶射皮膜を構成する溶射粒子の大きさは、溶射皮膜の断面組織の観察像を画像解析することで求めた。具体的には、基材上に形成された溶射皮膜を樹脂で固めた後、溶射皮膜を基材ごと当該基材の表面に垂直な方向で切断することで、溶射皮膜の断面を切り出した。そして、この溶射皮膜の任意の断面組織を所定の倍率の顕微鏡で観察することで得られた観察像について、気孔部と固相部とを分離する2値化を行い、これを画像解析ソフトを用いて解析することで、固相部を構成する溶射粒子の大きさ(円相当径)を測定した。なお、本明細書において、溶射皮膜を構成する溶射粒子の大きさの測定は、走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た2000倍の平面視像、若しくは「走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、SU8000シリーズ)により観察して得た20000倍の平面視像を用い、画像解析ソフト(MOUNTECH Co.,Ltd.製、Mac-View)を用いて画像解析することで行った。図3に、サンプル5の溶射材料を溶射して得られた溶射皮膜の断面組織のSEM像を例示した。溶射皮膜を構成する溶射粒子の大きさの測定に用いる観察像は、例えば、図3のように、セラミックス粒子の周囲長が30ピクセル以上となる解像度であるのが好ましい。 [Particle size of sprayed coating]
The results of measuring the average particle diameter of the particles constituting the thermal spray coating formed of the thermal spray materials of Samples 1 to 8 are shown in the column “Average particle diameter” of the thermal spray coating in Table 1.
Here, the size of the thermal spray particles constituting the thermal spray coating was obtained by image analysis of an observation image of the cross-sectional structure of the thermal spray coating. Specifically, after the thermal spray coating formed on the base material was hardened with resin, the thermal spray coating was cut in the direction perpendicular to the surface of the base material together with the base material to cut out a cross section of the thermal spray coating. Then, with respect to the observation image obtained by observing an arbitrary cross-sectional structure of the sprayed coating with a microscope having a predetermined magnification, binarization for separating the pore portion and the solid phase portion is performed, and this is applied to the image analysis software. By using and analyzing, the size (equivalent circle diameter) of the thermal spray particles constituting the solid phase portion was measured. In the present specification, the measurement of the size of the thermal spray particles constituting the thermal spray coating was obtained by observing with a scanning electron microscope (Scanning Electron Microscope: SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N) 2000. Image analysis software (MOUNTECH Co) using a 2 × 2 plane image or “20000 × 2 plane image obtained by observation with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, SU8000 series)”. The image was analyzed using a Mac-View) manufactured by., Ltd. Fig. 3 illustrates an SEM image of the cross-sectional structure of the sprayed coating obtained by spraying the sprayed material of Sample 5. The observation image used for the measurement of the size of the spray particles constituting the coating is, for example, a resolution in which the peripheral length of the ceramic particles is 30 pixels or more as shown in FIG. Preferably.
また、サンプル1~8の溶射材料により形成された溶射皮膜を構成する粒子の平均粒子径を測定した結果を、表1の溶射皮膜の「平均粒子径」の欄に示した。
ここで、溶射皮膜を構成する溶射粒子の大きさは、溶射皮膜の断面組織の観察像を画像解析することで求めた。具体的には、基材上に形成された溶射皮膜を樹脂で固めた後、溶射皮膜を基材ごと当該基材の表面に垂直な方向で切断することで、溶射皮膜の断面を切り出した。そして、この溶射皮膜の任意の断面組織を所定の倍率の顕微鏡で観察することで得られた観察像について、気孔部と固相部とを分離する2値化を行い、これを画像解析ソフトを用いて解析することで、固相部を構成する溶射粒子の大きさ(円相当径)を測定した。なお、本明細書において、溶射皮膜を構成する溶射粒子の大きさの測定は、走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、S-3000N)により観察して得た2000倍の平面視像、若しくは「走査型電子顕微鏡(Scanning Electron Microscope:SEM,株式会社日立ハイテクノロジーズ製、SU8000シリーズ)により観察して得た20000倍の平面視像を用い、画像解析ソフト(MOUNTECH Co.,Ltd.製、Mac-View)を用いて画像解析することで行った。図3に、サンプル5の溶射材料を溶射して得られた溶射皮膜の断面組織のSEM像を例示した。溶射皮膜を構成する溶射粒子の大きさの測定に用いる観察像は、例えば、図3のように、セラミックス粒子の周囲長が30ピクセル以上となる解像度であるのが好ましい。 [Particle size of sprayed coating]
The results of measuring the average particle diameter of the particles constituting the thermal spray coating formed of the thermal spray materials of Samples 1 to 8 are shown in the column “Average particle diameter” of the thermal spray coating in Table 1.
Here, the size of the thermal spray particles constituting the thermal spray coating was obtained by image analysis of an observation image of the cross-sectional structure of the thermal spray coating. Specifically, after the thermal spray coating formed on the base material was hardened with resin, the thermal spray coating was cut in the direction perpendicular to the surface of the base material together with the base material to cut out a cross section of the thermal spray coating. Then, with respect to the observation image obtained by observing an arbitrary cross-sectional structure of the sprayed coating with a microscope having a predetermined magnification, binarization for separating the pore portion and the solid phase portion is performed, and this is applied to the image analysis software. By using and analyzing, the size (equivalent circle diameter) of the thermal spray particles constituting the solid phase portion was measured. In the present specification, the measurement of the size of the thermal spray particles constituting the thermal spray coating was obtained by observing with a scanning electron microscope (Scanning Electron Microscope: SEM, manufactured by Hitachi High-Technologies Corporation, S-3000N) 2000. Image analysis software (MOUNTECH Co) using a 2 × 2 plane image or “20000 × 2 plane image obtained by observation with a scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, SU8000 series)”. The image was analyzed using a Mac-View) manufactured by., Ltd. Fig. 3 illustrates an SEM image of the cross-sectional structure of the sprayed coating obtained by spraying the sprayed material of Sample 5. The observation image used for the measurement of the size of the spray particles constituting the coating is, for example, a resolution in which the peripheral length of the ceramic particles is 30 pixels or more as shown in FIG. Preferably.
表1に示されるように、サンプル1の溶射材料は、比表面積が0.1m2/gと小さいため、低温プロセスであるHOVF溶射で溶射材料を十分に軟化・溶融させることができず、飛行してきた粒子を基板に付着させて製膜することができなかった。また、サンプル1の溶射材料については、平均粒径が24μmと極端に大きいわけではないものの、平均真円度が1.8と大きく、粉末供給機および溶射装置内での溶射材料の搬送にムラが生じるのが確認された。これは、サンプル1の溶射材料が溶融-粉砕法により調製されており、特段研磨等の処理等を施していないため、セラミックス粒子に角部が多く存在し、溶射材料の流動性が低下されたものと考えられる。なお、具体的には示していないが、かかる溶射材料であっても、高温プロセスであるプラズマ溶射法等を採用することで、溶射皮膜を形成することができる。ただし、その場合も、溶射材料の流動性が十分得られていないために、溶射材料の供給量が一定でなかったり、スピッティングが発生したりして、溶射皮膜の品質は必ずしも十分であるとは言えなかった。
As shown in Table 1, since the thermal spray material of Sample 1 has a small specific surface area of 0.1 m 2 / g, the thermal spray material cannot be sufficiently softened and melted by HOVF thermal spraying, which is a low temperature process. The deposited particles could not be deposited on the substrate. In addition, the thermal spray material of Sample 1 has an average particle diameter of 24 μm, which is not extremely large, but the average roundness is as large as 1.8, and the spray material is unevenly conveyed in the powder feeder and the thermal spraying apparatus. Was confirmed to occur. This is because the thermal spray material of Sample 1 was prepared by the melt-pulverization method and was not subjected to special polishing or the like, so that there were many corners in the ceramic particles, and the fluidity of the thermal spray material was reduced. It is considered a thing. Although not specifically shown, even with such a thermal spray material, a thermal spray coating can be formed by adopting a plasma spray method or the like which is a high temperature process. However, even in that case, since the fluidity of the thermal spray material is not sufficiently obtained, the supply amount of the thermal spray material is not constant, spitting occurs, and the quality of the thermal spray coating is not necessarily sufficient. I could not say.
サンプル2の溶射材料は、比表面積が0.4m2/gとサンプル1の溶射材料よりは大きいものの十分ではないため、低温プロセスであるHVOF溶射で溶射材料を軟化させて溶融粒子を基板に付着させることは可能であったが、十分に軟化されない粒子については成膜に寄与させることができなかった。また、サンプル2の溶射材料については、平均真円度が1.5とやや大きく十分な流動性が得られなかったため、粉末供給機および溶射装置内での溶射材料の搬送に若干のムラが生じるのが確認された。これは、サンプル2の溶射材料が、造粒-焼結法により調製されて平均真円度がサンプル1の溶射材料よりは低く抑えられているものの、十分に真球に近い形態にすることができなかったためであると考えられた。なお、サンプル2の溶射材料の平均アスペクト値は全サンプル中で最も小さかったが、かかる溶射材料の流動性に関しては平均アスペクト値からおおよそ推察できるものの、詳細な範囲までは十分に評価できないことが確認できた。なお、具体的には示していないが、かかる溶射材料であっても、プラズマ溶射法等を採用することで、溶射皮膜を形成することができる。ただし、その場合も、溶射材料の流動性が十分得られていないために、溶射材料の供給量が一定でなかったり、スピッティングが発生したりして、溶射皮膜の品質は必ずしも十分であるとは言えなかった。
Although the thermal spray material of sample 2 has a specific surface area of 0.4 m 2 / g, which is larger than the thermal spray material of sample 1, it is not sufficient. Therefore, the thermal spray material is softened by HVOF thermal spraying, which is a low temperature process, and the molten particles adhere to the substrate. However, particles that are not sufficiently softened could not contribute to film formation. In addition, the thermal spray material of Sample 2 has a slightly large average roundness of 1.5, and a sufficient fluidity was not obtained. Therefore, there is a slight unevenness in the conveyance of the thermal spray material in the powder feeder and the thermal spraying apparatus. It was confirmed. This is because the thermal spray material of sample 2 is prepared by a granulation-sintering method, and the average roundness is suppressed to be lower than that of the thermal spray material of sample 1, but the shape is sufficiently close to a perfect sphere. It was thought that it was because it was not possible. Although the average aspect value of the thermal spray material of Sample 2 was the smallest among all samples, the fluidity of such a thermal spray material can be roughly estimated from the average aspect value, but it has been confirmed that it cannot be fully evaluated up to the detailed range. did it. Although not specifically shown, even with such a thermal spray material, a thermal spray coating can be formed by employing a plasma thermal spraying method or the like. However, even in that case, since the fluidity of the thermal spray material is not sufficiently obtained, the supply amount of the thermal spray material is not constant, spitting occurs, and the quality of the thermal spray coating is not necessarily sufficient. I could not say.
一方で、サンプル3~8の溶射材料は、比表面積が0.5m2/g以上と十分に大きいため、上記のとおり、溶射材料の融点よりも低い温度でのHVOF溶射においても、溶射材料が十分に溶融および加熱されて、均質な皮膜を形成し得ることが確認できた。特にサンプル2および3の比較から、溶射用材料の平均粒子径が同じであっても、比表面積を0.5m2/g以上に増大させることで、より低温での溶射に好適に供することが可能なことが確認できた。その結果、溶射材料の飛散が少なく抑えられて、成膜速度が5μm/pass以上の生産性の良い成膜を行うことができた。また、サンプル3~8の溶射材料は、平均粒子径が30μm以下でありながらも20μm以上と十分に大きく、さらに平均真円度が1.5未満であるため、溶射に際して、粉末供給機および溶射装置内で詰まったりすることなく、一定の流量で溶射フレームに供給することができた。
On the other hand, since the thermal spray material of Samples 3 to 8 has a sufficiently large specific surface area of 0.5 m 2 / g or more, as described above, the thermal spray material is also used in HVOF thermal spraying at a temperature lower than the melting point of the thermal spray material. It was confirmed that the film could be sufficiently melted and heated to form a homogeneous film. In particular, from the comparison of samples 2 and 3, even if the average particle diameter of the thermal spray material is the same, the specific surface area can be suitably used for thermal spraying at a lower temperature by increasing the specific surface area to 0.5 m 2 / g or more. It was confirmed that it was possible. As a result, scattering of the spray material was suppressed, and a highly productive film formation rate of 5 μm / pass or more could be performed. Further, the thermal spray materials of Samples 3 to 8 have an average particle diameter of 30 μm or less, but are sufficiently large as 20 μm or more, and an average roundness of less than 1.5. It was possible to supply the spray frame at a constant flow rate without clogging in the apparatus.
なお、サンプル3~8の溶射材料によると、粒子径が5μm未満の微細で緻密な組織からなる溶射皮膜が形成できることもわかった。ここで、サンプル3~6の溶射材料はアルミナからなる。しかしながら、サンプル3~6の溶射温度はそれぞれ1800℃および1600℃とアルミナの融点の約2050℃よりも大幅に低い。また、サンプル7および8の溶射材料はイットリアおよびイットリア安定化ジルコニアからなる。しかしながら、サンプル7および8の溶射温度はそれぞれ2300℃および2500℃と、イットリアおよびイットリア安定化ジルコニアの融点の約2410℃および2600℃よりも大十分に低い。このように、ここに開示される溶射材料によると、このように溶射材料そのものの融点よりも低温でのHVOF溶射でも、十分に緻密で微細な組織からなる溶射皮膜を形成することが可能なことが確認できた。
It was also found that the thermal spray material of Samples 3 to 8 can form a thermal spray coating consisting of a fine and dense structure with a particle diameter of less than 5 μm. Here, the thermal spray materials of Samples 3 to 6 are made of alumina. However, the thermal spray temperatures of Samples 3-6 are significantly lower than 1800 ° C. and 1600 ° C., respectively, which is about 2050 ° C., which is the melting point of alumina. The thermal spray materials of Samples 7 and 8 are made of yttria and yttria stabilized zirconia. However, the thermal spray temperatures of Samples 7 and 8 are 2300 ° C. and 2500 ° C., respectively, well below the melting points of yttria and yttria stabilized zirconia of about 2410 ° C. and 2600 ° C. Thus, according to the thermal spray material disclosed here, it is possible to form a thermal spray coating composed of a sufficiently dense and fine structure even by HVOF thermal spraying at a temperature lower than the melting point of the thermal spray material itself. Was confirmed.
なお、サンプル3~8の溶射材料は、例えば図1および2に代表されるように、平均粒子径が6μm未満(例えば、0.01μm~3μm)と極微細な一次粒子が間隙をもって結合されることで形成されたセラミックス粒子から構成されている。したがって、フレームの温度が融点に満たなくても、かかる溶射材料は十分に軟化および溶融されて、好適に溶射皮膜を形成できたものと考えられる。すなわち、ここに開示される極微細な粒子が間隙をもって結合された二次粒子の形態のセラミックス粒子からなる溶射材料によると、例えば融点以下の低温プロセスであっても、高品質な溶射皮膜を生産性良く形成できることが示された。
In the thermal spray material of Samples 3 to 8, for example, as typified by FIGS. 1 and 2, the average particle diameter is less than 6 μm (for example, 0.01 μm to 3 μm) and very fine primary particles are bonded with a gap. It is comprised from the ceramic particle formed by this. Therefore, even if the temperature of the frame does not reach the melting point, it is considered that such a thermal spray material is sufficiently softened and melted to form a thermal spray coating suitably. That is, according to the thermal spray material composed of ceramic particles in the form of secondary particles in which ultrafine particles are bonded with a gap as disclosed herein, a high-quality thermal spray coating is produced even in a low-temperature process below the melting point, for example. It was shown that it can be formed with good properties.
なお、サンプル5~8の溶射材料は、一次粒子がナノ粒子もしくはそれに近い形態である。したがって、このような溶射材料を用いて形成される溶射皮膜を構成する溶射粒子の平均一次粒子径も凡そ1μm以下と微細化され、極めて緻密な皮膜組織が形成されることがわかった。かかるサンプル5~8の溶射材料から形成された溶射皮膜は、例えば、断面SEM観察により求められる気孔率が約1%以下と極めて緻密であり得る。この気孔率は、上記溶射皮膜の粒子径の算出時に求めた気孔部と固相部との面積から、気孔率=(気孔部面積)÷(気孔部面積+固相部面積)×100により算出される値である。また、サンプル8の溶射材料から形成された溶射皮膜は8%YSZから構成され、良好なイオン伝導特性を示し得る。したがって、この溶射皮膜は、例えば、SOFCセルにおける固体電解質等として好適に使用することができる。
Note that in the thermal spray materials of Samples 5 to 8, the primary particles are in the form of nanoparticles or a form close thereto. Therefore, it has been found that the average primary particle diameter of the thermal spray particles constituting the thermal spray coating formed using such a thermal spray material is refined to about 1 μm or less, and an extremely dense coating structure is formed. The thermal spray coating formed from the thermal spray material of Samples 5 to 8 can be extremely dense, for example, the porosity determined by cross-sectional SEM observation is about 1% or less. This porosity is calculated from the area of the pore portion and the solid phase portion obtained at the time of calculating the particle diameter of the sprayed coating by the following equation: Porosity = (pore portion area) ÷ (pore portion area + solid phase portion area) × 100 Is the value to be Moreover, the thermal spray coating formed from the thermal spray material of Sample 8 is composed of 8% YSZ, and can exhibit good ion conduction characteristics. Therefore, this thermal spray coating can be suitably used as, for example, a solid electrolyte in a SOFC cell.
以上、本発明を好適な実施形態により説明してきたが、こうした記述は限定事項ではなく、種々の改変が可能であることはいうまでもない。
As mentioned above, although this invention has been demonstrated by suitable embodiment, it cannot be overemphasized that such description is not a limitation matter and various modifications are possible.
Claims (10)
- 平均粒子径が30μm以下であって、比表面積が0.5m2/g以上のセラミックス粒子を含む、溶射材料。 A thermal spray material containing ceramic particles having an average particle diameter of 30 μm or less and a specific surface area of 0.5 m 2 / g or more.
- 前記セラミックス粒子は、一次粒子が間隙をもって3次元的に結合されてなる二次粒子の形態を有している、請求項1に記載の溶射材料。 The thermal spray material according to claim 1, wherein the ceramic particles have a form of secondary particles in which primary particles are three-dimensionally bonded with a gap.
- 前記一次粒子は、平均粒子径が6μm未満である、請求項2に記載の溶射材料。 The thermal spray material according to claim 2, wherein the primary particles have an average particle diameter of less than 6 µm.
- 前記セラミックス粒子は、平面視における平均真円度が1.5未満である、請求項1~3のいずれか1項に記載の溶射材料。 The thermal spray material according to any one of claims 1 to 3, wherein the ceramic particles have an average roundness in a plan view of less than 1.5.
- 前記セラミックス粒子は、平面視における平均アスペクト比が1.4未満である、請求項1~4のいずれか1項に記載の溶射材料。 The thermal spray material according to any one of claims 1 to 4, wherein the ceramic particles have an average aspect ratio in a plan view of less than 1.4.
- 前記セラミックス粒子は、平均フラクタル次元が1.07未満である、請求項1~5のいずれか1項に記載の溶射材料。 The thermal spray material according to any one of claims 1 to 5, wherein the ceramic particles have an average fractal dimension of less than 1.07.
- 安息角が35°未満である、請求項1~6のいずれか1項に記載の溶射材料。 The thermal spray material according to any one of claims 1 to 6, wherein an angle of repose is less than 35 °.
- 前記セラミックス粒子は、アルミナ、ジルコニア、イットリア、シリカ、炭化ケイ素、炭化ホウ素、窒化ケイ素、サイアロン、窒化アルミニウムおよびハイドロキシアパタイトからなる群から選択される1種または2種以上のセラミックス材料を含む、請求項1~7のいずれか1項に記載の溶射材料。 The ceramic particles include one or more ceramic materials selected from the group consisting of alumina, zirconia, yttria, silica, silicon carbide, boron carbide, silicon nitride, sialon, aluminum nitride, and hydroxyapatite. The thermal spray material according to any one of 1 to 7.
- セラミックス材料からなる溶射粒子が基材上に堆積されてなる溶射皮膜であって、
前記基材の表面に垂直な断面における前記溶射粒子の平均粒子径が5μm未満である、溶射皮膜。 A thermal spray coating in which thermal spray particles made of a ceramic material are deposited on a substrate,
The thermal spray coating whose average particle diameter of the said thermal spray particle in a cross section perpendicular | vertical to the surface of the said base material is less than 5 micrometers. - 基材の表面に請求項9に記載の溶射皮膜が備えられている、溶射皮膜付基材。 A substrate with a thermal spray coating, wherein the thermal spray coating according to claim 9 is provided on the surface of the substrate.
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