JPH0575824B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a composite spherical powder of metal and ceramics, and in particular, to forming an intermediate layer to improve bonding properties or alleviate thermal stress at the interface when coating a base metal with ceramics, etc. The present invention relates to a composite thermal spraying powder of metal powder and ceramic powder for use, and a method for producing the same. [Prior art and problems to be solved by the invention] Conventionally, by coating metal materials with ceramics, it has been possible to improve the properties of the base metal material such as ductility and toughness, as well as heat insulation, heat resistance, and wear resistance. Attempts to create mechanically superior composite materials with added properties such as strength and corrosion resistance have attracted attention in various fields, and various bonded bodies and thermal spraying methods have been developed. Among them, the conventional surface coating method seen in thermal spraying of ceramics is simply mechanical interlocking,
Even if a reaction layer is formed at the bonding surface, sufficient consideration is not given to the characteristics of the materials, and the combination of these results in large differences in thermal expansion coefficients, causing thermal stress and distortion at the interface, which is essentially This did not provide a solution to the problem of zygosity. Therefore, in order to improve the bonding strength between the base metal and the coating ceramic, an intermediate layer, which is a composite of an oxide and the metal-based powder, is interposed between the metal material and the coating ceramic. A method for solving the above-mentioned drawbacks has been devised (for example, Japanese Patent Application Laid-Open No. 62-222052). In this method, at the interface between the metal material and the intermediate layer, the metal and the metal of the same type existing in the intermediate layer are combined, or when the metal to be joined and the metal existing in the intermediate layer are different types, the interface is formed. Bonding is carried out by forming an intermetallic compound in consideration of strength, and on the other hand, a composition of the intermediate layer is selected that provides high bonding strength due to the reaction layer and anchoring effect at the interface between the intermediate layer and the coating ceramic material. Looking at the thermal spraying treatment methods for forming the intermediate layer that contributes to the improvement of bonding strength, there is a mixed thermal spraying method in which a mixed powder of two or more types is supplied onto the surface of the base metal while being mixed at the tip of a thermal spray nozzle. There is also an individual thermal spraying method in which a plurality of thermal spray powders forming an intermediate layer are individually supplied to the tip of a thermal spray nozzle. However, in the former case, segregation tends to occur due to differences in the specific gravity and particle size of the mixed powder at the supply source, and in the latter case, differences in fluidity due to the material, particle size, shape, etc. of the powder (especially , ceramic powder alone has extremely poor fluidity), it was not possible to secure the desired blending ratio to the thermal spray supply nozzle, and it was not possible to quantitatively form the composite intermediate layer. Therefore, in order to solve these drawbacks, the present invention immobilizes and spherizes ceramic powder onto metal powder in an air flow by mechanical impact means, and forms a diffusion layer at the interface of both powders. The object of the present invention is to provide a composite thermal sprayed powder for forming an intermediate layer with excellent fluidity in which the components of the composite powder are kept at a predetermined blending ratio, and a method for producing the same. [Means and effects for solving the problem] In order to achieve the above object, the mixing ratio due to segregation in the supply source of the plurality of thermal sprayed powders forming the intermediate layer or the difference in fluidity of each powder. In order to eliminate fluctuations in By attaching fine particles and applying a continuous impact action to the adhered composite powder in an air stream using a rotary disk or the like having a large number of impact pins (hereinafter referred to as "mechanical impact means")
JP-A No. 62-221434), at the same time as it becomes spherical, ceramic powder is immobilized on the main component metal powder,
The present invention provides a composite spherical powder in which a diffusion layer is formed at the interface between metal powder and ceramic powder, and a method for producing the same. Alternatively, after adhering a predetermined amount of ceramic powder to the surface of the main component metal, which has been sphericalized in advance, in the same manner as described above, the ceramic powder is fixed to the main component metal powder by mechanical impact means in an air flow. The present invention provides a composite powder in which a diffusion layer is formed and a method for producing the same. [Function] According to the composite spherical powder configured as described above, various selected main component metal powders and ceramic powders are used to improve the bondability between the base metal and the dissimilar coating material and to alleviate thermal stress. A desired blending ratio of the composite body can be secured. This fixes the fine powder of the coating material to the powder of the main component of the base metal in advance at a predetermined ratio and forms a diffusion layer. This takes advantage of the fact that fluctuations in the blending ratio due to differences in fluidity are eliminated. In addition, the composite thermal sprayed powder is made by applying an impact or striking action to the individual surfaces of the composite powder using mechanical impact means to force the composite powder, which is made by adhering ceramic powder to the main component metal powder. It can be produced by a so-called dry method of immobilization. Furthermore, the diffusion layer of the powder prevents the composite powder from separating or peeling and is firmly bonded, so it also contributes to the bonding properties of the thermally sprayed intermediate layer and allows the desired intermediate layer to be formed. Can be provided. In addition, by selecting amorphous powder as the base metal powder, it is possible to freely select the blending ratio of the components, and the spheroidization process and fixation process, which were conventionally performed separately, can be performed simultaneously. It is possible to provide a composite thermal sprayed powder for forming an intermediate layer that is inexpensive and has excellent bonding strength and fluidity, and a method for producing the same. [Example] Hereinafter, a composite spherical powder of metal powder and ceramic powder according to the present invention and a method for producing the same will be explained in detail. The powder according to the present invention is a composite thermal sprayed powder for forming an intermediate layer, in which an oxide powder or a coated ceramic main component powder is immobilized on a metal powder whose main component is a metal material as a base material. A uniform intermediate layer is formed by spraying onto the surface of the metal material using
At this interface (base metal/intermediate layer), metals of the same type existing in the intermediate layer are combined, or in the case of different metals, they are combined by forming an intermetallic compound. Furthermore, coating ceramic powder is thermally sprayed onto the metal material onto which the intermediate layer (sprayed base) has been thermally sprayed, and bondability is achieved by generating a chemical reaction layer and using the anchoring effect at the composite intermediate layer/coated ceramic interface. It forms a ceramic coating of metal with good quality. The metal material used as the base material is not particularly limited, but includes, for example, ferrous materials (SUS, heat-resistant steel, etc.), non-ferrous materials (AI alloy, Cu alloy, etc.), heat-resistant metal materials,
The composite intermediate layer, which is thermally sprayed to have a predetermined function, is made of, for example, the main component metal (Al) of the base metal.
Ittria (Y ₂ O ₃ 0.1 to 20 mol%) alone or added to ittria and a part of the coating ceramic component, or added to the main component of the base metal with a lower oxide (in this case, (contains no non-ferrous materials) or active metals (Ti,
It is selected by considering the base metal and the coating ceramic, and is thermally sprayed under predetermined conditions on the processed surface. There are, for example, the following two methods for producing the composite thermal spray powder for the intermediate layer selected in this way. (1) Using amorphous powder as the main component metal powder and adhering ceramic powder to its surface, a composite powder is made, and at the same time, the composite powder is spheroidized by mechanical impact means, and at the same time, the metal powder is (2) A method of producing a composite thermal sprayed powder in which ceramic powder is immobilized on the surface or inside of the material to form a diffusion layer at the interface; and (2) spherical particles are used as the main component metal powder, 2. A method of producing a composite thermal sprayed powder in which a composite powder is made with ceramic powder attached, and the ceramic powder is immobilized on the surface of the main component metal by mechanical impact means to form a diffusion layer at the interface. There are two ways. FIG. 1 is a conceptual diagram showing the above manufacturing method. When using irregularly shaped powder,
Since it has a larger surface area than spherical powder, it is possible to widen the range of blending ratios of ceramic powder. FIG. 2 shows an embodiment of the mechanical impact means for producing the composite powder of the present invention, and is a device having the impact impact means (hereinafter referred to as "powder impact device"). The powder impact device includes one casing,
2 a stator, 3 a rotary disk that rotates at high speed within the casing 1, 4 a plurality of impact pins (blades) provided radially around the outer periphery of the rotary disk 3, and 5 one end of which is a part of the inner wall of the stator 2. 6 is a raw material input port, and 7 is a processing powder discharge port provided by cutting out a part of the stator. Consists of an on-off valve. The operation is a batch operation, and the composite powder, in which a predetermined blending ratio of ceramic powder is attached to the surface of the main component metal powder using a mixer, etc., is fed into the machine from the input port 6, and then the composite powder is fed into the machine through the input port 6, and then the composite powder is fed into the machine through the input port 6, and then Board 3
It is carried toward the outer circumference of the rotary disk while being dispersed by the effect of 5, and is put into the machine again and subjected to the same action repeatedly to be uniformly fixed and sphericalized in a short time, and the discharge port 7 is opened to collect the treated product.
By using a powder processing apparatus having such an impact means, the ceramic powder is firmly fixed to the main component metal, and the fixed composite powder is spheroidized. When the composite spherical powder is fixed and spheroidized, impact force forms a diffusion layer of ceramic powder at the main component metal interface. The diffusion layer integrates the individual composites, prevents them from separating or peeling during thermal spraying, and further contributes to improving the bondability of the intermediate layer after thermal spraying. Examples of intermediate layer-forming composite thermal spray powders produced using the present powder processing apparatus are shown in Table 1 and will be further described below. Table 1 shows the composition of the composite thermal spray powder, the operating treatment conditions for manufacturing, and the fluidity (JIS Z 2502 "Metal powder fluidity test method"), which is an indicator of the fluidity of the product. show. Flow rate indicates the time required for a given amount of powder to flow out of an orifice. Therefore, the lower the fluidity, the better the fluidity. If the fluidity is very poor, it may not flow out from the orifice and measurement may not be possible. Furthermore, since the fluidity largely depends on the specific gravity of the substance, it is difficult to compare different types of materials, but the composite spheroidization process allows substances that cannot flow alone to maintain fluidity. The flow rates of irregularly shaped products of Al alloy, SUS, and Cu are unmeasurable, 36, and 37, respectively, and the flow rates of spherical powder obtained by spheroidizing these metal powders are 58, 14, and 16, respectively. , Table 1 shows values that are almost the same as the fluidity of the present composite spherical powder. This shows that by making the ceramic powder, which does not flow by itself, into a composite spheroid as described above, the fluidity was improved to the level of that of the individual metal powder. 3 to 9 are photographs of composite powders according to examples of the present invention. Example 1 The following is an example of a composite powder in which the surface area of the main component metal is expanded to make it easier to control the amount ratio of ceramics. In this case, an appropriate amount of ceramic powder is directly mixed with the amorphous main component metal powder, and then spherical and composite are simultaneously performed by mechanical impact means, which saves labor in the process. T-1 in Table 1 has an average grain size of 39μ as the main component metal.
It is processed by mixing 5 mol% of amorphous Al alloy powder with a diameter of 1.2 mm and Y ₂ O ₃ powder with an average particle size of 3.5 μm as ceramics.The fluidity of this composite powder is 56, and it has excellent fluidity. I understand. Figure 3a is a SEM image of the amorphous Al alloy powder used as the raw material. b is a scanning electron microscopy (SEM) image of the appearance of the spherical powder, and c is a SEM image of the cross section of the composite spherical powder. d is an SEM image and an X-ray image of the above cross section taken by an X-ray microanalyzer (EPMA).
As seen in the figure, Y ₂ O ₃ is immobilized inside the spherical powder. A diffusion layer is formed at the interface between the Al alloy powder and the Y ₂ O ₃ powder, resulting in a strong bond. The composite powder is sprayed as a base onto an Al alloy round bar,
Furthermore, when PSZ powder was thermally sprayed and the joint strength was measured, a tensile strength of 4 kg/mm ² or more was obtained, and the breakage mainly occurred between the adhesive and the PSZ surface.
It was found that both thermal sprayability and fluidity (JIS Z 2502) were superior to a simple mixture of Al alloy powder Y ₂ O ₃ powder. Example 2 T-2 in Table 1 has an average particle size of 39μ as the main component metal.
This composite powder is processed by mixing 5 mol% of amorphous Al alloy powder with 5 mol% of ZrO ₂ with an average particle size of 1.9 μm and Y ₂ O ₃ powder with an average particle size of 3.5 μm as ceramics. was 54. Figures 4a and 4b show SEM images of the appearance and cross section of the composite spherical powder. Example 3 T-3 in Table 1 has an average particle size of 58μ as the main component metal.
m amorphous SUS powder, Y 2 O 3 powder with an average particle size of 3.5 μm as ceramics, and Y ₂ O ₃ powder with an average particle size of 11.4 μm as ceramics.
Approximately 5 mol% of Al ₂ O ₃ was mixed with metal powder and post-treated, and the fluidity of this composite powder was 30. Figures 5a and 5b show SEM images of the appearance and cross section of the composite spherical powder. In SUS powder, the same ceramic entrainment effect as seen in Al alloy powder occurs, resulting in a strong composite. Example 4 T-4 in Table 1 has an average particle size of 58μ as the main component metal.
The composite powder was post-treated by mixing 4 mol% of amorphous SUS powder with 4 mol% of partially stabilized zirconia (PSZ) powder as ceramics, and the fluidity of this composite powder was very good and the fluidity improved to 17. Figure 6a shows a SEM image of the appearance of the composite spherical powder. Example 5 T-5 in Table 1 has an average particle size of 62μ as the main component metal.
The composite powder had a fluidity of 14.m irregularly shaped copper powder was mixed with partially stabilized zirconia (PSZ) powder as ceramics, and the fluidity of this composite powder was 14. Figure 7a shows a SEM image of the appearance of the composite spherical powder. Example 6 T-6 in Table 1 has an average particle size of 62μ as the main component metal.
m amorphous copper powder and ceramics with an average diameter of
It was post-treated by mixing 6.46 mol% of Al ₂ O ₃ with a diameter of 11.4 μm, and the fluidity of this composite powder was 16. Figures 8a and 8b show SEM images of the appearance and cross section of the composite spherical powder. Ceramics entrainment similar to that observed in Al alloy powder occurs in Cu powder, resulting in a strong composite. Example 7 As shown in T-7 in Table 1, Al alloy spherical powder with an average particle diameter of 43 μm, which was obtained by previously spheroidizing irregularly shaped Al alloy powder as the main component metal, was used as the raw material. The Al alloy powder has an average particle size of 3.5 μm.
After mixing _Y2O3 powder at a predetermined ratio ( _4.5mol %),
Rotating disk peripheral speed 100m/by using mechanical impact means
s, the treatment time was 6 min. SEM images of the external shape and cross section of this composite powder-treated product are shown in Figure 9 a and b.
A SEM image and an X-ray image of the cross section are shown in FIG. 9c.
The core of the spherical powder is surrounded by Al, the outer periphery is surrounded by Y and O, and it can be seen that a composite of Al alloy powder and Y ₂ O ₃ powder has been established. As in Example 1, a diffusion phenomenon of Al and Y ₂ O ₃ was observed between the outer periphery of the Al nucleus and Y ₂ O ₃ .
It was found that Y ₂ O ₃ was firmly bonded to the alloy. The fluidity of the composite powder is as shown in Table 1.
It had a value of 57 and was found to be a powder like fluid. The fluidity of conventional ceramic individual powders cannot be measured except for PSZ (granulated products), and therefore, the composite powder with excellent fluidity according to the present invention could not be provided by the individual thermal spraying method. Other methods include mixing main component metal (excluding ferrous metals) powder with lower oxides (e.g. FeO, etc.) or active metals (Ti, Nb, etc.) and ittria to produce composite powder using mechanical impact means. It was also found that diffusion and entrainment phenomena occur between the main component metal and the oxide, resulting in a strong bond and a composite powder with excellent fluidity. The composite powder of active metal and ittria is used as an intermediate layer (base) when materials with strong covalent bonds such as carbide (SiC, etc.) and nitride (Si ₃ O ₄ , etc.) ceramics are sprayed as coating ceramics. suitable for

【table】

〔Effect of the invention〕

As explained above, according to the composite spherical powder of metal powder and ceramic powder of the present invention and the method for producing the same, it is possible to improve bonding performance and to reduce thermal stress when a dissimilar coating material such as ceramics is bonded to a base metal. In order to alleviate the problem, we adopted a composite powder for the intermediate layer depending on the base metal and coating material, fixed fine oxide powder on the base metal main component metal powder using mechanical impact means, made it into a sphere, and By forming a diffusion layer at the interface during the process, it is possible to ensure a stable blending ratio of ingredients and appropriate fluidity as a powder, eliminating blockages that tend to occur during conventional thermal spraying.
It is possible to provide a composite thermal spray powder for forming an intermediate layer using a composite spherical powder of metal powder and ceramic powder that does not cause troubles such as separation and segregation, and a method for producing the same. In order to evaluate the performance of the thermal spray coating using the composite spherical powder, the present applicant prepared an Al substrate (base material) with a length of 10 cm, a width of 5 cm, and a thickness of 0.6 cm as shown in FIG.
Then, a thermal spray powder of the present invention or a commercially available intermediate layer forming powder was added, and a commercially available ceramic was added thereon as shown in Table 2.
Samples were prepared by plasma spraying under the thermal spraying conditions shown in Table 3, and repeatedly heated/cooled under the conditions shown in Table 3 to repeatedly measure thermal shock resistance. In Figure 10, 8 is an Al substrate, 9 is an intermediate layer, and 10 is a ceramic layer. The thickness of the sprayed intermediate layer is
The thickness of the ceramic layer is 0.3 mm, and the width and length of both the intermediate layer and the ceramic layer are 5 cm. The apparatus used for the thermal shock resistance test is shown in FIG. In FIG. 11, 11 is a sample for repeated thermal shock resistance measurement in which the intermediate layer and ceramic layer shown in FIG. 15 is a compressed air pipe for cooling the sprayed layer, 16 is a compressed air pipe for cooling the base material, 1
Reference numeral 7 denotes a K-type thermocouple inserted into a hole in the core of the thermal spraying target on the back side of the Al substrate to measure the temperature of the sample. Further, 18 is a natural gas supply source, 19 is an oxygen supply source, and 20 is a compressed air supply source for cooling.

【table】

[Table] Table 4 shows the results of the thermal shock resistance test. As shown in Table 4, three types of composite thermal spray powder of the present invention for the intermediate layer with different blending ratios of yttoria, a commercially available amorphous thermal spray powder (granulated product), and a ceramic layer were used. Two types of commercially available spherical thermal spray powders (granulated products) were used. In this table,
The number of times the heat-cooling cycle is repeated until peeling is the number of times the heat-cooling cycle is repeated until the sprayed coating starts peeling off. The numerical values listed in this table are the average values of the results obtained twice under the same conditions. In E-2, 3, and 4, the heat/cool cycle is
The sprayed coating did not peel off even after 2000 repetitions. When the composite thermal sprayed powder of the present invention is used for the intermediate layer, the bondability is much better than when a commercially available intermediate layer thermal sprayed powder is used, or when nothing is thermally sprayed as the intermediate layer. The number of repetitions of heating and cooling cycles until peeling was 3 to 7 times more than when a commercially available intermediate layer thermal spray powder was used and when no intermediate layer was thermally sprayed. In this way, by thermally spraying the composite thermal spraying powder for forming the intermediate layer, which is forcibly fixed on the intermediate layer (thermal spraying base) by mechanically impacting the base metal powder and the ceramic powder. , it was possible to alleviate thermal stress and greatly improve the bonding properties of ceramics.

【table】 [Brief explanation of drawings]

Figure 1 is a conceptual diagram of manufacturing composite thermal spray powder.
a is amorphous metal powder, 2a is spherical metal powder, 1b
and 2b are ceramic powders, 1c and 2c
Composite powders 1d and 2d, in which ceramic powder is adhered to metal powder, represent states in which ceramic powder is firmly fixed to metal powder. FIG. 2 shows a powder impacting device having an impact impacting means, which is an embodiment used for producing a composite thermal sprayed powder for forming an intermediate layer. Figures 3 to 9 show photographs and X-ray photographs of the particle structure of the composite sprayed powder based on the examples in Table 1, and Figure 3a shows a photograph of the particle structure of the amorphous Al alloy raw material powder. b and Fig. 4 to Fig. 9 a are photographs of the particle structure after composite processing; Fig. 3 c, Fig. 4 b, and Fig. 5
FIG. b, FIG. 8b, and FIG. 9b are cross-sectional views of grain structure photographs. In addition, Fig. 3 d and Fig. 9 c are X-ray photographs, and the symbol Y in the upper left is yttrium, O is oxygen,
Al indicates the aluminum component. FIG. 10 shows a sample on which a sprayed coating was formed to confirm the effects of the present invention, and FIG. 11 shows an apparatus used for a thermal shock resistance test of the sample. Explanation of symbols, 1...Casing, 2...Stator, 3...Rotary disk, 4...Impact pin (blade), 5...Circulation circuit, 6...Raw material input port, 7...
...Treatment powder, 8...Al substrate, 9...Intermediate layer, 1
0...Ceramics layer, 11...Sample, 12
... Gas burner, 15, 16 ... Compressed air piping for cooling, 17 ... K type thermocouple, 18 ... Natural gas supply source, 19 ... Oxygen supply source, 20 ... Compressed air supply source.

Claims (1)

[Claims] 1. A spherical metal powder obtained by repeatedly subjecting a mixed powder of metal powder and ceramic powder, which are the main components of a metal base material, to a mechanical impact while being dispersed in an air flow. Composite thermal spray powder for forming an intermediate layer between ceramic powder and ceramic powder. 2. The composite thermal sprayed powder for forming an intermediate layer of metal powder and ceramic powder according to claim 1, wherein the main component metal powder is a ferrous material, a non-ferrous alloy material, a heat-resistant metal material, or an active metal. . 3 The ceramic powder includes yttoria (Y ₂ O ₃ 0.1 to 20 mol%), a mixed powder of yttoria and coated ceramics, partially stabilized zirconia (PSZ 0.1 to 20 mol%), and alumina (Al ₂ O ₃ 0.1 to 20 mol%).
20mol%) or lower oxides (1 to 80mol%)
The composite thermal sprayed powder for forming an intermediate layer of metal powder and ceramic powder according to claim 1. 4 A mixed powder consisting of an amorphous or spherical metal powder and a predetermined ratio of ceramic powder is dispersed in an air stream and repeatedly subjected to mechanical impact, whereby the metal powder is A method for producing a composite thermal sprayed powder for forming an intermediate layer of metal powder and ceramic powder, which simultaneously immobilizes the ceramic powder on the surface of a body and spheroidizes the ceramic powder. 5. By attaching ceramic powder in advance to the surface of an amorphous or spherical metal powder, and repeatedly applying a mechanical impact action while dispersing it in an air flow, Simultaneously fixes and spheroidizes ceramic powder.
A method for producing a composite thermal spray powder for forming an intermediate layer of metal powder and ceramic powder.