JP2010133021A - Particle for thermal spraying - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal particle for thermal spraying which is not oxidized during thermal spraying, and further, can be easily and inexpensively produced. <P>SOLUTION: The particle for thermal spraying is obtained by providing the surface of a mother particle composed of a metal with a covering layer formed by a surface treatment agent. Suitably, the covering layer covers the whole of the surface of the metal particle, and further, it is suitable that, until immediately before the collision against the surface of the base material as a target, at least a part of the covering layer is held in a state of being left on the surface of the metal particle so as to prevent the oxidation of the metal particle. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to oxidation suppression in a thermal spraying process of thermal spray particles, particularly thermal spray metal particles.

Thermal spraying is one of the methods for forming a metal coating, and the metal powder for thermal spraying is introduced into, for example, a plasma flame or a combustion flame to give heat and kinetic energy, and sprayed toward the surface of the target substrate. Is done.
However, when sprayed in the atmosphere, the sprayed metal powder is exposed to high temperature and undergoes oxidation, and the characteristics of the sprayed metal powder may not be sufficiently exhibited in the sprayed coating. In addition, alloy compositions have been developed for various purposes such as strength, corrosion resistance, and wear resistance, but the susceptibility to oxidation varies depending on the metal elements that make up the alloy, so the resulting thermal spray coating alloy The composition is different from the thermally sprayed alloy particles, and desired properties may not be obtained. In particular, when an easily oxidizable metal element that easily binds to oxygen is included, or when the metal powder has a small particle size, it is susceptible to oxidation.

In Patent Document 1, the surface of an MCrAlY powder (M is one or more of Fe, Ni, Co) used for forming a corrosion-resistant sprayed coating in a gas turbine blade or the like is subjected to high-temperature oxidation resistance such as Pt, Re, Ta, or Nb. It is described that the high-temperature oxidation resistance of the sprayed powder is improved by coating with a reactive metal.
However, the high temperature oxidation resistant metal is very expensive, and the coating must be performed by a plating method, a PVD method, or the like. In any case, the process is complicated, and the plating method has a problem of waste liquid.

Patent 3043745

  The present invention has been made in view of the background art described above, and an object of the present invention is to provide metal particles for thermal spraying that are difficult to oxidize during the thermal spraying process and that can be easily and inexpensively manufactured.

  As a result of intensive studies by the present inventors, the metal particles for thermal spraying are used as mother particles, and the surface is treated with a surface treatment agent in advance to form a coating layer, whereby a high-temperature oxidizing atmosphere is formed during the thermal spraying process It has been found that the core mother particles are not oxidized even when exposed to water and a good metal spray coating can be obtained, and the present invention has been completed.

That is, the thermal spraying particle according to the present invention is characterized in that it has a coating layer formed of a surface treatment agent on the surface of a base particle made of metal.
In the thermal spraying particle of the present invention, it is preferable that the coating layer covers the entire surface of the base particle.
In addition, it is preferable that at least a part of the coating layer remains on the surface of the base particle to prevent oxidation of the metal base particle until just before the surface of the base material that is the target collides.
Moreover, it is suitable that the surface treating agent amount with respect to the mother particles is 0.1 to 10% by mass.
Moreover, it is preferable that the mother particle is a metallic glass having a ΔTx of 30K or more.
Further, it is preferable that the metal of the mother particle contains a reactive metal element that is oxidized by thermal spraying in the atmosphere.

Moreover, it is suitable that the surface treatment agent is a reactive organic surface treatment agent having reactivity with the mother particles.
The reactive organic surface treatment agent is preferably a reactive silicone compound containing a Si—H group.
The reactive organic surface treatment agent is preferably a coupling agent, and more preferably a Si-based, Ti-based, Al-based, or Zr-based coupling agent.
The surface treatment agent can also be a non-reactive surface treatment agent that does not have reactivity with metal particles.
In addition, it is preferable that the surface treatment agent is sodium silicate.

The thermal spray coating according to the present invention is obtained by thermal spraying any one of the aforementioned thermal spraying particles.
The thermal spray coating of the present invention is preferably obtained by thermal spraying the thermal spray particles in the air.
Moreover, it is preferable that the average dispersed particle diameter of the coating layer residue remaining in the sprayed coating is 5 μm or less.
Further, in the case of a thermal spray coating obtained by thermal spraying particles for thermal spraying having a coating layer formed using a silicon compound as a surface treating agent, the coating layer residue remaining in the thermal spray coating is 4 vol% or less in terms of Si. Is preferred.

  The particles for thermal spraying of the present invention constitute the mother particles because the coating layer formed on the surface of the metal mother particles as the core suppresses the oxidation of the mother particles even when exposed to a high-temperature oxidation frame during the thermal spraying process. The properties inherent to the metal to be applied can be sufficiently exhibited even in the sprayed coating. In addition, the fine mother particles contribute to reducing the risk of dust explosion and preventing spitting. Further, the coating layer of the present invention can be easily formed on the surface of the mother particle by a surface treatment agent. Moreover, the function and property of the thermal spray coating can be improved by supporting child particles such as ceramic on the coating layer.

It is sectional drawing which shows typically an example of the particle | grains for thermal spraying concerning this invention. It is sectional drawing which shows typically an example of the particle | grains for thermal spraying concerning this invention. It is an electron micrograph (x500 times) of (a) before the coating treatment and (b) after the coating treatment of the Fe ₄₃ Cr ₁₆ Mo ₁₆ C ₁₅ B ₁₀ metal glass gas atomized powder. (A) Zr ₆₀ Al ₁₅ Ni _7.5 Co _2.5 Cu ₁₅ powder (38 to 53 μm) without coating layer, (b) Zr ₆₀ Al ₁₅ Ni _7.5 Co _2.5 Cu ₁₅ powder with coating layer It is an X-ray-diffraction result of the sprayed coating obtained by spraying (38-53 micrometers), respectively.

(A) Cu ₅₀ Zr ₄₀ Al ₁₀ metal glass powder (25 to 53 μm) without coating layer, (b) Cu ₅₀ Zr ₄₀ Al ₁₀ metal glass powder (25 to 53 μm) with coating layer, respectively It is the result of the X-ray diffraction of the sprayed coating. The distribution of Si and O by the AES analysis of the thermal spray coating obtained from the thermal spray particles coated with (a) 0.5% by mass and (b) 1% by mass of the surface treatment agent with respect to the mother particles. FIG. It is a figure which shows Si distribution by the SEM photograph and EDX analysis of the thermal spray coating obtained from the particle | grain for thermal spraying which coat | covered 3 mass% surface treating agent with respect to the mother particle. (A) Appearance and (b) Cross-sectional SEM photograph (2000 times) of particles for thermal spraying in which child particles (alumina fine powder) are supported on a coating layer (surface treatment agent: methyl hydrogen polysiloxane) on the surface of the mother particles It is. It is a figure which shows distribution of Al by the cross-sectional SEM photograph (500 times) of the thermal spray coating obtained from the child particle (alumina fine powder) carrying thermal spray particle, and EPMA analysis.

3 is an optical micrograph of a cross-section of a thermal spray coating obtained from thermal spray particles in which child particles (low softening point glass fine powder) are supported on a coating layer (surface treatment agent: methyl hydrogen polysiloxane) on the surface of a mother particle. Ti and Bi by EPMA analysis of the cross section of the thermal spray coating obtained from the thermal spray particles obtained by supporting the child particles (low softening point glass fine powder) on the coating layer (surface treatment agent: methyl hydrogen polysiloxane) on the surface of the mother particles It is a figure which shows distribution. (A) appearance and (b) SEM photograph of cross section of particles for thermal spraying in which child particles (low softening point glass fine powder) are supported on a coating layer (surface treatment agent: water glass + stearic acid) on the surface of the mother particles 2000 times).

  The particles for thermal spraying of the present invention have a coating layer formed by a surface treatment agent on the surface of base particles (core) made of metal. By this coating layer, the oxidation of the mother particles introduced into the thermal spray frame is suppressed. Therefore, the coating layer preferably covers the entire surface of the metal particles from the viewpoint of suppressing oxidation.

  FIG. 1 is a cross-sectional view schematically showing an example of thermal spray particles according to the present invention. In FIG. 1, a thermal spraying particle 10 has spherical base particles 2 made of metal and a coating layer 4 covering the surface thereof. In addition, although the coating layer 4 is one layer in FIG. 1, it can also be set as the multilayered structure of two or more layers as needed. Further, as shown in FIG. 2, the coating layer 4 can additionally include one or more child particles 6.

<Mother particles>
The metal constituting the core particle serving as the core is not particularly limited, and may be either a pure metal or an alloy, and the structure may be either crystalline or amorphous. Moreover, the composite material of a metal and another nonmetallic component can also be used as needed.
The antioxidant effect of the coating layer is particularly useful when the core mother particle is a reactive metal that is oxidized by thermal spraying. For example, a metal material containing a combustible metal such as Zr, Mg, Ti, or Al is usually highly reactive.

Also, since the 1980s, so-called metallic glasses have been found that have extremely high stability against crystallization in a supercooled liquid state as compared with conventional amorphous alloys. It has been reported.
Metallic glass is characterized by showing a clear glass transition and a wide supercooled liquid temperature region before crystallization when heated.

  That is, when the thermal behavior of metallic glass is examined using DSC (Differential Scanning Calorimeter), as the temperature rises, a broad wide endothermic temperature region appears starting from the glass transition temperature (Tg), and crystallization starts. It turns into a sharp exothermic peak at temperature (Tx). When further heated, an endothermic peak appears at the melting point (Tm). Each temperature varies depending on the type of metallic glass. One characteristic of the metallic glass is that the temperature range ΔTx = Tx−Tg between Tg and Tx is the supercooled liquid temperature range, and ΔTx is as large as 10 to 130K. A larger ΔTx means higher stability of the supercooled liquid state against crystallization. In a conventional amorphous alloy, such thermal behavior is not recognized, and ΔTx is almost zero.

In recent years, it has also been reported that an amorphous phase metallic glass spray coating can be obtained by thermal spraying an amorphous phase metallic glass powder (Japanese Patent Laid-Open No. 2006-21400).
As the base particles of the present invention, such a metal glass powder and further an amorphous phase metal glass powder are preferably used.
Moreover, when it is going to obtain the thermal spray coating of an amorphous phase, it is preferable to use the metal glass whose (DELTA) Tx is 30K or more.

  The shape of the mother particle is not particularly limited as long as it is usually used for thermal spraying, and examples thereof include a plate shape, a chip shape, a granular shape, a powder shape, and a spherical shape. It is. As used herein, the term “spherical” refers to a spherical shape having a ratio of the shortest diameter / longest diameter of particles (true sphere ratio) of 0.7 to 1. Such spherical mother particles are produced by a known method such as a gas atomizing method or a water atomizing method.

The particle size of the base particles is not particularly limited as long as it is in a range that allows thermal spraying. In general, the particle size of the spray particles is in the range of 1 to 100 μm.
In order to increase the denseness of the thermal spray coating, it may be desired to use thermal spray particles having a small particle size. However, when the particle size is reduced, the oxidation rate is increased and the thermal spray coating properties are significantly deteriorated. The present invention is particularly useful for such a mother particle having a small particle diameter, for example, particularly useful for a mother particle of 25 μm or less, and further 10 μm or less.

  Also, as the particle size decreases, the risk of dust explosion generally increases. Furthermore, spitting (melted particles inside the nozzle (barrel) of the spraying gun adheres and solidifies), resulting in a decrease in productivity, and the adhered solidified material inside the barrel peels off and forms in the sprayed coating. The problem of mixing easily occurs. The present invention is also useful for solving these problems.

<Coating layer>
The coating layer may disappear from the surface of the metal particles by volatilization or combustion immediately before the sprayed particles reach the target substrate surface and collide, but in order to sufficiently prevent the oxidation of the mother particles Is preferably maintained on the surface of the metal particles until it collides with the surface of the substrate. As a result of suppressing oxidation of the mother particles due to thermal spraying, the coating layer itself may be oxidized during thermal spraying and converted to oxide.

  When the particles for thermal spraying collide with the substrate surface with the coating layer and / or its oxide remaining, the coating layer and / or its oxide (hereinafter sometimes referred to as “coating layer residue”) is In some cases, the sprayed coating is broken, deformed, or scattered and at least a part thereof is included in the sprayed coating. When the coating layer residue adversely affects the sprayed coating, it is preferable that the coating layer residue be finely dispersed. For example, the dispersed particle size of the coating layer residue in the sprayed coating is preferably 10 μm at the maximum and 5 μm or less on average.

The thermal spraying particles of the present invention can be obtained by coating the surface of the core base particles with a surface treatment agent by a known method.
The amount of the surface treatment agent used may be appropriately set according to the target coating layer, but it is preferable to use an amount sufficient to cover the entire surface of the base particles. Typically, in order to sufficiently coat the surface of the metal particles, it is preferable to use the surface treatment agent in an amount of 0.1% by mass or more, more preferably 0.5% by mass or more based on the mother particles. On the other hand, even if an excessive amount of surface treatment agent is used, an improvement in the effect of suppressing oxidation cannot be expected.In contrast, a large amount of coating layer residue remains in the sprayed coating, and depending on the type of coating layer residue, film performance is adversely affected. May give. In order to reduce the coating layer residue in the sprayed coating or to finely disperse the coating layer residue, the surface treatment agent is preferably 10% by mass or less, more preferably 5% by mass or less, based on the mother particles. For example, when the thermal spraying particles in which a coating layer is formed using a silicon compound as a surface treatment agent, the coating layer residue in the thermal spray coating can be 4 vol% or less. Further, since the cohesiveness of the thermal spray particles obtained by the coating treatment becomes stronger and the feedability to the thermal spraying device tends to deteriorate when the surface treatment agent is increased, the surface treatment is more preferably performed on the mother particles. An agent is 3 mass% or less. The layer thickness of the coating layer is preferably about 1 to 30 nm. This is not the case when the coating layer carries child particles.

  The surface treatment agent is not limited as long as it can form a coating layer having an ability to inhibit oxidation on the surface of the mother particles, but a hydrophobic coating agent is preferably used from the viewpoint of moisture resistance. Typical examples include silicone compounds such as dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, alkyl-modified silicone, alkoxy-modified silicone, fluorine-modified silicone, trimethylsiloxysilicic acid, acrylic silicone, and silicone resin. Fluorine compounds such as perfluoroalkyl group-containing esters, perfluoropolyethers, perfluoroalkyl group-containing polymers; silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconium coupling agents, etc. Coupling agents; hydrocarbons such as liquid paraffin, squalane, petrolatum, lanolin, microcrystalline wax, polyethylene wax; higher alcohols; zinc laurate, Acyl amino acid compounds such as lauroyl lysine; magnesium stearate, metal soaps of aluminum stearate and organic surface treatment agent such as dextrin fatty acid esters are not limited thereto. Moreover, 1 type, or 2 or more types may be used for an organic surface treating agent.

The coating layer formed of the surface treatment agent is preferably solid at least at room temperature (25 ° C.) in terms of handleability.
The coating layer may be formed on the surface of the metal mother particle by physical adsorption and / or chemical bonding, and any of a non-reactive coating agent and a reactive coating agent may be used, but during storage or thermal spraying. In order not to damage the coating layer, it is preferable that the coating layer is firmly formed on the surface of the mother particle by chemical bonding using a reactive coating agent.

  Examples of the organic surface treatment agent capable of forming such a coating layer include reactive coating agents such as organohydrogenpolysiloxanes and coupling agents. The reactive coating agent is usually dispersed or dissolved in an appropriate liquid (water or organic solvent) and uniformly adhered to the entire surface of the mother particle by spraying, mixing, dipping, etc., followed by baking treatment (condensation reaction or crosslinking by heating). Although it is immobilized on the surface of the metal particles by a known method such as formation of a chemical bond by reaction or the like, or mechanochemical treatment, it is not limited thereto. In the case where the amorphous phase metallic glass powder is used as the mother particle, the heating in forming the coating layer is preferably performed at a crystallization start temperature or lower.

  Examples of the organohydrogenpolysiloxane include, but are not limited to, methylhydrogenpolysiloxane, methylhydrogenpolysiloxane / dimethylpolysiloxane copolymer, and tetramethylcyclotetrasiloxane. Further, non-reactive silicones such as organopolysiloxanes such as dimethylpolysiloxane and decamethylcyclopentasiloxane can be used in combination.

  Silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltri Examples include methoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-chloropropyltrimethoxysilane.

  Titanate coupling agents include isopropyl stearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphate) titanate, tetra (2,2- Examples include diaryloxymethyl-1-butyl) bis (ditridecyl phosphate) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, and bis (dioctyl pyrophosphate) ethylene titanate.

  Examples of the aluminate coupling agent include acetoalkoxyaluminum diisopropylate, aluminum diisopropoxy monoethyl acetoacetate, aluminum trisethyl acetoacetate, aluminum trisacetylacetonate and the like.

  Examples of the zirconium coupling agent include zirconium tetrakisacetylacetonate, zirconium dibutoxybisacetylacetonate, zirconium tetrakisethylacetoacetate, zirconium tributoxymonoethylacetoacetate, zirconium tributoxyacetylacetonate, and the like.

Examples of the inorganic surface treatment agent include water-soluble metal salts, metal alkoxides, etc., but sodium salt of metasilicic acid (Na ₂ SiO ₃ ), Na ₄ SiO ₄ , Na ₂ Si ₂ O ₅ , Na ₂ Si ₄ O _9. Various sodium salts of silicic acid such as water glass are particularly desirable.
The coating layer can be formed using an inorganic surface treatment agent by a known method (coating method, deposition method, hydrolysis method, etc.). For example, an inorganic surface treatment agent dispersed or dissolved in an appropriate liquid (water or organic solvent) is uniformly adhered to the entire surface of the mother particle by spraying, mixing, or dipping, and then, if necessary, baking treatment, mechanochemical treatment, etc. , A method of immobilizing on the surface of metal particles by a known method; a method of precipitating a coating layer made of a metal oxide on the surface of the mother particles by dispersing the mother particles in an inorganic surface treating agent solution and hydrolyzing them. However, it is not limited to these.
Moreover, 1 type, 2 or more types may be used for an inorganic surface treating agent, and you may use it in combination with an organic surface treating agent.

<Child particles>
In the present invention, in order to improve the mechanical, electrical, magnetic, optical, chemical, thermal, or other functions and properties of the obtained sprayed coating, the child particles made of an inorganic substance are added to the coating layer. It can be supported by. For example, ceramics generally have higher hardness, heat resistance, corrosion resistance, and the like than metals, and thus these functions can be imparted to the sprayed coating by using ceramics as the child particles.
Further, ordinary ceramics have a high melting point (or softening point) and do not melt or soften even during the thermal spraying of metal mother particles. When such ceramics are used as the child particles, the denseness of the sprayed coating can be improved.

  The ceramic is not particularly limited, but includes oxide-based ceramics containing silica, alumina, zirconia, calcium oxide, magnesia, or the like, or carbides, borides, nitrides, or the like. Non-oxide ceramics can be used. 1 type (s) or 2 or more types can be used for a child particle.

  When forming a coating layer containing child particles, for example, a method of treating mother particles using a dispersion / mixing of child particles in a surface treatment agent, or treating a mixture of child particles with mother particles with a surface treatment agent However, it is not limited to these.

Although the quantity of a child particle is suitably set according to the target effect, Preferably it is 0.1-10 mass% with respect to a mother particle, Furthermore, it is 0.5-5 mass%. If the amount of the child particles is too small, the effect cannot be obtained sufficiently, and if the amount is too large, it may not be supported by the coating layer.
The shape of the child particles is not particularly limited, but the particle size is preferably 0.1 to 5 μm so that it can be firmly supported on the coating layer on the surface of the mother particles. If the particle size is too small, the child particles tend to aggregate, and if it is too large, the particles may be detached from the coating layer or the thermal spray coating characteristics of the mother particles may be impaired.

The thermal spray particles of the present invention can be used in any thermal spraying method. For example, there are atmospheric pressure plasma spraying, low pressure plasma spraying, flame spraying, high-speed flame spraying (HVOF), arc spraying, etc., but it is useful for spraying performed in an oxidizing atmosphere such as the atmosphere, and is particularly effective for high-speed flame spraying. Is.
Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.

Test Example 1 Metal atomized gas atomized powder (amorphous, Tg = 885K, ΔTx = 65K, 25 μm under sieve) composed of a composition of thermal spray particles Fe ₄₃ Cr ₁₆ Mo ₁₆ C ₁₅ B ₁₀ having a coating layer , A mixed solution of 1 part by mass of methyl hydrogen polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., KF-9901) and 1 part by mass of ethanol was added and mixed uniformly with a sample mill. This was baked in a drying oven at 270 ° C. for 5 hours. Thereafter, the nodule was crushed with a sample mill, and the particles for spraying having a coating layer were obtained by separating the sieve under 45 μm.

FIG. 3 is an SEM photograph (× 500 times) of the particles before (a) coating treatment and (b) after coating treatment. As shown in FIG. 3, the particles for thermal spraying obtained in Test Example 1 were approximately spherical and the entire surface was coated with the coating layer, and no change in shape or aggregation due to the coating treatment was observed.
In addition, the element distribution of the thermal spray particles obtained in Test Example 1 was examined by Auger Electron Spectroscopy (AES). As a result, it was confirmed that the coating layer on the surface of the mother particle was about 3 nm.

Test Example 2 Oxidation Inhibitory Effect In the same manner as in Test Example 1, a metal glass gas atomized powder (amorphous, ΔTx = 84K) having a composition of Zr ₆₀ Al ₁₅ Ni _7.5 Co _2.5 Cu ₁₅ was coated, Thermal spray particles having a coating layer were obtained. Thermal spraying was performed using the particles for thermal spraying and, as a comparative example, a metal glass powder not coated (without a coating layer). The thermal spraying conditions are as follows.

(Spraying conditions)
―――――――――――――――――――――――――――――――――――――――
Thermal spray apparatus: HVOF apparatus (JP-5000, manufactured by PRAXAIR-TAFA)
Barrel length 4 inches)
Base material: SUS304L plate (surface blasted finish)
Powder carrier gas: N ₂
Fuel: Kerosene 2.5GPH-Oxygen 2000SCFH
Thermal spray distance: 180mm
―――――――――――――――――――――――――――――――――――――――

4 (a) is _{Zr 60 Al 15 Ni 7.5 Co 2.5} Cu 15 powder without the coating layer (38~53μm), (b) is a coating layer of _{Zr 60 Al 15 Ni 7.5 Co 2} . ₅ Cu ₁₅ powder (38~53μm) is an X-ray diffraction results of the thermal sprayed coating obtained by spraying respectively.
As shown in FIG. 4 (a), an oxide peak was observed in the thermal spray coating in the metal glass powder having no coating layer, whereas from the metal glass powder having the coating layer as shown in FIG. 4 (b). In the obtained sprayed coating, such an oxide peak was hardly recognized.

In addition, for a metal atomized gas atomized powder (amorphous, ΔTx = 55K) having a composition of Cu ₅₀ Zr ₄₀ Al _10, a sprayed coating was prepared under the above-mentioned spraying conditions, and the same applies to the case with a coating layer and without a coating layer. Compared to.
5 (a) is _Cu 50 _Zr 40 _{Al 10} metallic glass powder without the coating layer (25~53μm), (b) is _Cu 50 _Zr 40 _{Al 10} metallic glass powder has coating layer (25~53μm) respectively spraying It is the result of the X-ray diffraction of the sprayed coating obtained by doing.
From FIG. 5 also, it is understood that the oxidation of the mother particle metal component is suppressed by the coating layer formed on the mother particle surface.
Thus, the coating layer formed on the surface of the mother particle can suppress the oxidation of the mother particle metal component.

Test Example 3 Coating Layer Residue In Test Example 1, a coating layer was prepared in the same manner except that the amount of methylhydrogenpolysiloxane was 0.5% by mass or 1% by mass with respect to the raw material powder (mother particles). Thermal spray particles were produced and sprayed in the same manner as in Test Example 2.
The element distribution of each sprayed coating was examined by Auger Electron Spectroscopy (AES). FIG. 6A shows the Si and O distributions of the sprayed coating obtained from the powder of 0.5% by mass of the treatment agent and FIG.
As can be seen from FIG. 6, in any sprayed coating, the coating layer residue was finely dispersed in the sprayed coating, the dispersion average particle diameter was 5 μm or less, and there were no dispersed particles exceeding 10 μm. These become clearer when the figure is color-mapped.

In addition, in Test Example 1, the same applies except that the amount of methylhydrogenpolysiloxane was 3% by mass and the amount of ethanol was 2% by mass with respect to the raw material powder (mother particles). Particles were produced and sprayed as in Test Example 2.
The result analyzed by FE-SEM (JEOL Co., Ltd. JSM-7001F) and EDX (JEOL Co., Ltd. JED-2300) is shown in FIG. In FIG. 7, the Si distribution by EDX is obtained by binarizing the color into black and white, and the black portion indicates Si. The coating layer residue was finely dispersed in the sprayed coating, and the average dispersed particle size was about 3.9 μm, and there were no dispersed particles exceeding 10 μm. Moreover, the coating layer residue contained in the thermal spray coating was about 3.6 vol% as the amount of Si.

Test Example 4 Surface treatment agent In Test Example 1, coating treatment was performed using various surface treatment agents and solvents as shown in Table 1 below to produce particles for thermal spraying (only in the case of water glass, the baking condition was 110). (C, 24 hours).
As shown in Table 1, thermal spray particles having the entire surface of the base particles coated were obtained when any surface treatment agent was used. All of the thermal spray coatings obtained from these thermal spray particles according to Test Example 2 exhibited a halo pattern having no oxide peak in the X-ray diffraction pattern.
In addition, when there was too much surface treating agent, there existed a tendency for a thermal spraying particle to produce aggregability and to reduce the thermal sprayability.

Test Example 5 Explosive Lower Limit Concentration Zr ₆₀ Al ₁₅ Co _2.5 Ni _7.5 Cu ₁₅ used in Test Example 2 is a very active Zr-based metallic glass, and the lower explosive lower concentration of the powder of 25 μm or less is about 100 g. / M ³ (measured in accordance with JIS Z8818 flammable dust explosion lower limit concentration measurement method).
On the other hand, when this powder was coated in the same manner as in Test Example 1 to form a coating layer, the lower explosion limit of 25 μm or less was about 500 g / m ³ .
Thus, by forming the coating layer, it is possible to reduce the risk of dust explosion to a level where there is almost no explosive concern.

Test Example 6 Compounding of child particles (1)
Metal glass gas atomized powder (amorphous, Tg = 885K, ΔTx = 65K, 10 to 25 μm) composed of Fe ₄₃ Cr ₁₆ Mo ₁₆ C ₁₅ B ₁₀ is added to 95 parts by mass of γ-alumina fine powder (2 to 3 μm). ) 5 parts by mass in advance with a mechano-hybrid mixer (Mitsui Mining Co., Ltd.), and 1 part by weight of methyl hydrogen polysiloxane (KF-9901 manufactured by Shin-Etsu Chemical Co., Ltd.) and 2 parts by mass of ethanol. The mixture was added and further mixed. This was baked in a drying oven at 270 ° C. for 5 hours. Thereafter, the nodules were crushed with a mechano-hybrid mixer, the bottom of the 45 μm sieve was collected, and fine particles of 10 μm or less were further cut by air classification to obtain particles for thermal spraying.
FIG. 8 shows (a) appearance of the obtained particles, and (b) cross-sectional SEM photograph (magnified 2000 times). From FIG. 8, it was confirmed that the entire surface of the substantially spherical mother particle was coated with a coating layer having a thickness of about 2 to 3 μm carrying alumina fine particles.

Using this thermal spraying particle, a thermal spray coating was obtained in the same manner as in Test Example 2. For comparison, particles for thermal spraying were prepared without using γ-alumina fine powder, and a thermal spray coating was obtained in the same manner.
As a result, as can be seen from Table 2 below, the hardness of the thermal spray coating could be remarkably increased by allowing the child particles to be present in the coating layer.
In addition, the sprayed coating cross section was analyzed with a distributed electron beam microanalyzer (EPMA: Electron).
As a result of investigation by Probe Micro Analyzer, Al was scattered at the boundary portion (grain boundary) of the deposited spray particles.

  FIG. 9 shows a cross-sectional SEM photograph (500 times) and an AES analysis result of a thermal spray coating obtained by thermal spraying particles for thermal spraying with child particles on a SUS substrate. As a result, aluminum was observed in the sprayed coating, indicating that alumina was dispersed. This becomes clearer when the figure is color-mapped.

Test Example 7 Compounding of child particles (2)
A metal atomized gas atomized powder (amorphous, Tg = 758K, ΔTx = 45K, 10-25 μm) having a composition of Fe ₇₆ P ₅ Si _5.7 B _9.5 C _3.8 is added to 95 parts by mass of a glass fine powder ( Asahi Glass Co., Ltd. ASF1094, transition point 733K, softening point 793K, center particle size 1.0 μm) 5 parts by mass are mixed in advance with a mechano hybrid mixer (Mitsui Mine Co., Ltd.), and methyl hydrogen polysiloxane ( A mixed solution of 1 part by weight of Shin-Etsu Chemical Co., Ltd. KF-9901) and 2 parts by weight of ethanol was added and further mixed. This was baked in a drying oven at 270 ° C. for 5 hours. Thereafter, the nodules were crushed with a mechano-hybrid mixer, the bottom of the 45 μm sieve was collected, and fine particles of 10 μm or less were further cut by air classification to obtain particles for thermal spraying.
Also in this case, as in Test Example 6, the entire spherical metal glass mother particle surface was coated with the coating layer, and particles for thermal spraying in which the glass fine particles were held in the coating layer were obtained.

Further, a thermal spray coating was obtained in the same manner as in Test Example 2 using the thermal spray particles. FIG. 10 shows an optical micrograph of the obtained sprayed coating cross section.
The cross section of the obtained sprayed coating was analyzed with a distributed electron beam microanalyzer (EPMA: Electron).
As a result of investigation by Probe Micro Analyzer, as shown in FIG. 11, Bi and Ti derived from glass were widely present at the boundary portion (grain boundary) of the deposited spray particles. This is presumably because the glass powder used as the child particles had a relatively low softening point and softened during spraying. This becomes clearer when the figure is color-mapped.

Test Example 8 Compounding of child particles (3)
In Test Example 7, an ethanol solution of methyl hydrogen polysiloxane was mixed with water glass [(Yes) Hayashi Chemical Water Glass No. 3 (components: SiO ₂ 30%, NaO 10%, water 60%, solid content 40% by mass)] 10 Instead of the mixture of part by mass and 2 parts by mass of stearic acid, spray particles were produced in the same manner except that the baking temperature was 100 ° C., and using these spray particles, thermal spraying was performed in the same manner as in Test Example 2. A coating was obtained.
In the same manner as in Test Example 7, the particles for thermal spraying were particles for thermal spraying in which the entire surface of the substantially spherical metallic glass mother particles was coated with a coating layer supporting glass fine particles. FIG. 12 shows (a) appearance and (b) cross-sectional SEM photograph (magnified 2000 times) of the obtained thermal spraying particles.

Claims (16)

  A thermal spraying particle comprising a coating layer formed of a surface treatment agent on a surface of a base particle made of metal.   The thermal spraying particle according to claim 1, wherein the coating layer covers the entire surface of the base particle.   3. The thermal spraying particle according to claim 1 or 2, wherein at least a part of the coating layer is maintained on the surface of the base particle until it collides with the surface of the base material as a target to suppress oxidation of the metal base particle. Thermal spray particles characterized by that.   The thermal spraying particle according to any one of claims 1 to 3, wherein the amount of the surface treatment agent relative to the base particle is 0.1 to 10% by mass.   The thermal spraying particle according to any one of claims 1 to 4, wherein the base particle is a metallic glass having a ΔTx of 30K or more.   The thermal spraying particle according to any one of claims 1 to 5, wherein the metal of the mother particle contains a reactive metal element that is oxidized by thermal spraying in the atmosphere.   The thermal spraying particle according to any one of claims 1 to 6, wherein the surface treatment agent is a reactive organic surface treatment agent having reactivity with the mother particle.   The thermal spraying particle according to claim 7, wherein the reactive organic surface treatment agent is a reactive silicone compound containing a Si—H group.   The thermal spraying particle according to claim 7, wherein the reactive organic surface treatment agent is a coupling agent.   The thermal spraying particle according to claim 9, wherein the coupling agent is a Si-based, Ti-based, Al-based, or Zr-based coupling agent.   The thermal spraying particle according to any one of claims 1 to 6, wherein the surface treatment agent is a non-reactive surface treatment agent having no reactivity with metal particles.   The thermal spraying particle according to any one of claims 1 to 6, wherein the surface treatment agent is sodium silicate.   A thermal spray coating obtained by thermal spraying the thermal spraying particles according to claim 1.   The thermal spray coating according to claim 13, wherein the thermal spray coating is obtained by thermal spraying the thermal spray particles in the atmosphere.   The thermal spray coating according to claim 13 or 14, wherein the average dispersed particle size of the coating layer residue remaining in the thermal spray coating is 5 µm or less.   The thermal spray coating according to any one of claims 13 to 15, wherein the thermal spray coating is obtained by thermal spraying particles for thermal spraying having a coating layer formed using a silicon compound as a surface treatment agent, and remains in the thermal spray coating. The thermal spray coating, wherein the coating layer residue is 4 vol% or less in terms of Si.