JP5070910B2 - Ceramic matrix composite member and method for producing ceramic matrix composite member - Google Patents

Description

  The present invention relates to a ceramic matrix composite member and a method for producing a ceramic matrix composite member, and more particularly to a ceramic matrix composite member having excellent adhesion strength between a substrate and a coating layer and a method for producing the same.

  2. Description of the Related Art Conventionally, a ceramic matrix composite material (Ceramic Matrix Composite: hereinafter abbreviated as CMC) made of ceramic fibers and a ceramic matrix has been used as a material for jet engine shroud parts and turbine parts. When CMC is used as a substrate for such applications, generally an environmental resistant coating (EBC) layer is formed on the surface of the CMC substrate. The environment-resistant coating layer improves heat resistance, oxidation resistance, corrosion resistance (especially water vapor (thinning resistance) resistance), and free-cutting properties against high-temperature gas environments. For example, Patent Document 1 to Patent Document 4 As shown in FIG. 2, those composed of rare earth oxides (silicates), hafnia (IVA group metal oxides), SAS (Strontium-Alumino-Silicate), and the like are known.

However, the environment-resistant coating layer generally has a thermal expansion coefficient of 5 to 10 × 10 ⁻⁶ / K and a difference in thermal expansion coefficient from a CMC base material having a thermal expansion coefficient of about 3 × 10 ⁻⁶ / K. Is very big. For this reason, conventionally, the residual stress resulting from the difference in thermal expansion between the environmental resistant coating layer and the CMC base material may cause cracks in the environmental resistant coating layer or the environmental resistant coating layer may peel off. It was a problem.

Various solutions have been made so far to solve this problem. For example, as shown in FIG. 20A, an intermediate layer having a thermal expansion coefficient intermediate between the environmental resistant coating layer 15 and the CMC base material 11 between the environmental resistant coating layer 15 and the CMC base material 11. The method of forming 13 is mentioned. Examples of the intermediate layer 13 include those made of barium strontium aluminosilicate, mullite, hafnon, and the like. By forming the intermediate layer 13, the stress generated by the difference in thermal expansion between the environmental resistant coating layer 15 and the CMC 11 can be relaxed in a stepwise manner. The intermediate layer 13 shown in FIG. 20A is formed by, for example, a method of spraying a material to be the intermediate layer 13 such as barium strontium aluminosilicate, mullite, and hafnon on the surface of the CMC base material 11.
In this case, when the adhesive force (adhesion strength) between the CMC substrate 11 and the intermediate layer 13 is low, a new problem is that peeling occurs at the interface. As shown in FIG. 20 (a), by forming an active metal such as Si, rare earth silicide, or Ti between the CMC base material 11 and the intermediate layer 13 as the bond layer 12, the chemical adhesive strength (adhesion strength) is increased. Can be improved. The bond layer 12 is formed on the surface of the CMC base material 11 by, for example, a method of thermally spraying a material that becomes a bond layer such as Si, rare earth silicide, or Ti under reduced pressure.

Further, as another technique for solving the above problem, as shown in FIG. 20B, there is a method of forming an environment resistant coating layer 15 on the CMC base material 11 having a groove 11a on the surface. By providing the groove 11 a on the surface of the CMC base material 11, it is possible to obtain an anchor effect that improves the adhesion between the environmental resistance coating layer 15 and the CMC base material 11. Can increase the physical adhesive strength.
JP 2006-193830 A US Patent Application Publication No. 2006/0112295 JP 2006-52126 A JP 2005-200226 A

  However, in the method shown in FIG. 20A, when the bond layer 12 is formed using an active metal such as Si, rare earth silicide, or Ti, Si, rare earth silicide, Ti, or the like constituting the formed bond layer 12 is formed. The active metal changes to a stable oxide or silicate. Since the change from the active metal to the oxide or silicate is a change accompanied by a volume change, when the bond layer 12 is formed on the entire surface of the CMC base material 11, the intermediate layer 13 and the environmental resistant coating layer 15 are peeled off. End up. However, if a region where the bond layer 12 is not formed is provided on a part of the CMC base material 11 so that the intermediate layer 13 and the environment-resistant coating layer 15 do not peel off, the CMC base material 11 has a denseness for protection. Will be insufficient.

  In addition, when the method shown in FIG. 20B is used, the thermal expansion coefficient mismatch between the environment-resistant coating layer 15 and the CMC base material 11 cannot be alleviated. In some cases, peeling may occur, and it is difficult to obtain an environmentally resistant coating layer 15 having a stable quality.

The present invention has been made in view of the above problems, and can reduce the thermal expansion coefficient mismatch between the coating layer and the CMC base material, and can improve the adhesion between the coating layer and the CMC base material. An object is to provide a base composite member.
Further, the present invention provides a method for producing a ceramic matrix composite member that can alleviate a mismatch in thermal expansion coefficient between a coating layer and a CMC substrate, and can improve adhesion between the coating layer and the CMC substrate. The purpose is to provide.

The ceramic matrix composite member of the present invention is made of a ceramic matrix composite material comprising ceramic fibers and a ceramic matrix attached to the ceramic fibers, and has a substrate having a coated surface on which a coating layer is formed, and the coated surface A stress relief material having a thermal expansion coefficient between the substrate and the coating layer on the coated surface side of the substrate. have a stress relieving layer formed by impregnating, said stress relaxation material, characterized by comprising an oxide ceramic, a sintering shrinkage small flame sintered material than the oxide ceramic.

  In the ceramic-based composite member, the base material has a plurality of pores, and the pores exposed on at least the coated surface of the pores are filled pores filled with the stress relaxation material. The stress relaxation layer is formed between the surface to be coated and the stress relaxation material filled in the filled pores located at the deepest position from the coated surface among the filled pores. It can be characterized by that.

The ceramic matrix composite member may be characterized in that the ratio of the filled pores among the pores existing in the stress relaxation layer increases as the coating layer is approached.
Further, the ceramic matrix composite member may include an intermediate layer made of the stress relaxation material and integrated with the stress relaxation layer between the stress relaxation layer and the coating layer. .
In the ceramic matrix composite member, the stress relaxation material may have a thermal expansion coefficient in the range of more than 3 to 6 [× 10 ⁻⁶ / K]. .

In the ceramic matrix composite described above, the stress relaxation material, can be made containing the SiC and _Yb 2 SiO _5.

In the ceramic matrix composite member, the ceramic fiber and / or the ceramic matrix may be made of SiC.
In the ceramic matrix composite described above, the coating layer may be made of HfO _2.

In order to solve the above problems, a method for producing a ceramic matrix composite member according to the present invention comprises a ceramic matrix composite material comprising ceramic fibers and a ceramic matrix attached to the ceramic fibers, and a coating layer is formed. A ceramic-based composite member manufacturing method comprising: a substrate having a coated surface; and a coating layer formed on the coated surface, wherein a thermal expansion coefficient is on the coated surface side of the substrate. A relaxation layer forming step of forming a stress relaxation layer by impregnating a stress relaxation material that is a value between the substrate and the coating layer; and a coating step of forming the coating layer on the stress relaxation layer of the substrate. only including, the relaxed layer forming step, the base material in the slurry to be the stress relaxation material by sintering Including a step of impregnating and a step of sintering the slurry adhering to the base material. It includes a raw material powder containing a small hardly-sinterable material, and a dispersion medium composed of a sol and a solvent that contribute to promoting bonding by sintering the oxide ceramic powder during sintering .

The ceramic matrix composite member of the present invention includes a stress relaxation layer formed by impregnating a stress relaxation material having a thermal expansion coefficient between the substrate and the coating layer on the surface to be coated of the substrate. Since it has, the stress relaxation layer can relieve the mismatch of the thermal expansion coefficient between the coating layer and the substrate, and the adhesion between the coating layer and the substrate can be improved.
Moreover, in the ceramic matrix composite member of the present invention, the stress relaxation layer is impregnated with the stress relaxation material having a thermal expansion coefficient between the substrate and the coating layer on the coated surface side of the substrate. Therefore, the stress relaxation layer can provide an anchor effect that improves the adhesion between the coating layer and the substrate, and can increase the physical adhesive force between the coating layer and the substrate. .

  In the method for producing a ceramic matrix composite member according to the present invention, the surface to be coated of the base material is impregnated with a stress relaxation material having a thermal expansion coefficient between the base material and the coating layer. Since it is a method including a relaxation layer forming step for forming a stress relaxation layer, it is possible to alleviate the mismatch of the thermal expansion coefficient between the coating layer and the substrate, and to improve the adhesion between the coating layer and the substrate. The ceramic matrix composite member of the present invention having the obtained stress relaxation layer is obtained.

“First Embodiment”
Hereinafter, an embodiment of a ceramic matrix composite member and a method for producing a ceramic matrix composite member according to the present invention will be described with reference to the drawings.
FIG. 1 is an enlarged schematic cross-sectional view showing a part of a ceramic matrix composite member of the present invention. A ceramic matrix composite member 10 shown in FIG. 1 has a substrate 1, a stress relaxation layer 2, an intermediate layer 3, and a coating layer 5.

The substrate 1 is made of a ceramic matrix composite material (CMC) 20 shown in FIG. The CMC 20 shown in FIG. 2 is composed of ceramic fibers 21 and a ceramic matrix 22. The CMC 20 has a thermal expansion coefficient of about 3 [× 10 ⁻⁶ / K] and has a plurality of pores (not shown in FIG. 2). In this embodiment, the CMC 20 has a porosity ((pore volume / CMC volume) × 100) of 5% to 60%, preferably about 20%.
The ceramic fiber 21 may be a two-dimensional fabric in which a predetermined fiber bundle made of C fiber, SiC fiber, or the like is oriented in the axial direction and the circumferential direction, a braided fabric, or a triaxial direction in which the fiber bundles are orthogonal to each other. An oriented three-dimensional fabric is used. A braided woven fabric is a woven fabric composed of fibers in an axial direction and fibers entangled with a slightly inclined axial fiber called a braid, which is not completely circumferential, and has the same structure as a braid. Moreover, it is preferable to use what laminated | stacked about 3-50 layers for a two-dimensional fabric and a braided fabric.
The ceramic matrix 22 is made of C, SiC, Si ₃ N ₄ or the like, and is attached to the ceramic fibers 21. Among such CMCs 20, in particular, the ceramic fiber 21 and the ceramic matrix 22 are both made of C or SiC, the ceramic fiber 21 is made of C, and the ceramic matrix 22 is made of SiC. preferable.

  Moreover, in FIG. 1, the code | symbol 1a has shown the to-be-coated surface in which the coating layer 5 is formed. On the coated surface 1 a side of the base material 1, a stress relaxation layer 2 that is impregnated with a stress relaxation material described later is formed. Further, among the plurality of pores of the substrate 1, the plurality of pores exposed on the surface to be coated 1a are filled with a stress relaxation material to form the filled pores 1b. As shown in FIG. 1, in the base material 1, the space between the coated surface 1 a and the stress relaxation material filled in the filled pores 1 b existing at the deepest position from the coated surface 1 a among the filled pores 1 b. The stress relaxation layer 2 is used.

The thickness of the stress relaxation layer 2 (the distance between the stress relaxation material filled in the filled pores 1b existing at the deepest position from the coated surface 1a and the coated surface 1a) is about 0.2 mm to 30 mm. It is preferable that the thickness is about 0.5 mm to 10 mm. If the thickness of the stress relaxation layer 2 is less than the above range, the anchor effect for improving the adhesion between the coating layer 5 and the substrate 1 may not be sufficiently obtained. Moreover, since manufacture will become difficult when the thickness of the stress relaxation layer 2 exceeds the said range, it is unpreferable.
In the ceramic matrix composite member shown in FIG. 1, the ratio of the filling pores 1 b in the stress relaxation layer 2 increases as the coating layer 5 is approached. In FIG. 1, in order to make the drawing easy to see, only a part of the pores filled with the stress relaxation material is illustrated among the pores uniformly present in the entire substrate 1, and the stress relaxation material is filled. Illustration of pores that are not performed is omitted.

An intermediate layer 3 made of a stress relaxation material and integrated with the stress relaxation layer 2 is provided between the stress relaxation layer 2 and the coating layer 5.
The thickness of the intermediate layer 3 is preferably about 0.005 mm to 2 mm, and more preferably about 0.01 mm to 0.5 mm. If the thickness of the intermediate layer 3 is less than the above range, the effect of increasing the physical adhesive force between the coating layer and the substrate by providing the intermediate layer 3 may not be sufficiently obtained. On the other hand, if the thickness of the intermediate layer 3 exceeds the above range, pores and cracks inherent in the intermediate layer are increased, which may reduce the strength of the intermediate layer, which is not preferable.
The stress relaxation material constituting the stress relaxation layer 2 and the intermediate layer 3 has a thermal expansion coefficient of a value between the substrate 1 and the coating layer 5, specifically, a thermal expansion coefficient of 1 to 6 [ × 10 ⁻⁶ / K] is preferable. Also. It is preferable that the stress relaxation material is excellent in heat resistance, oxidation resistance, and corrosion resistance against a high-temperature gas environment and does not cause a volume change due to a change in crystal phase between room temperature and 1400 ° C.

In the present embodiment, as the stress relaxation material, a material including an oxide ceramic and a hard-to-sinter material whose sintering shrinkage is smaller than that of the oxide ceramic is used.
As the oxide ceramic, it is preferable to use one having excellent heat resistance and environmental resistance and having a thermal expansion coefficient in the range of 1 to 10 [× 10 ⁻⁶ / K]. Specific examples of oxide ceramics include Yb ₂ SiO ₅ , Yb ₂ SiO ₅ , Er ₂ SiO ₅ , yttrium silicate (Y ₂ SiO ₅ ), rare earth silicates such as erbium silicate, aluminosilicate, and magnesium silicate. And various kinds of silicates, single oxides such as Al ₂ O ₃ and SiO ₂ , glass such as borosilicate glass (Pyrex glass (registered trademark)), and the like can be used. Among these oxide ceramics, rare earth silicates such as Yb ₂ SiO ₅ , Y ₂ SiO ₅ , and Er ₂ SiO ₅ have a slow decomposition rate in high-temperature air containing water vapor. When CMC is used, it is preferable because CMC thinning due to water vapor can be suppressed. Especially, Yb ₂ SiO _5, which is a rare earth silicate having a thermal expansion coefficient of 6.1 [× 10 ⁻⁶ / K] and close to CMC and having high chemical affinity with SiC, which is preferably used as a material for CMC, is used. Is preferred.

Non-oxide ceramics such as carbides and nitrides that have a smaller sintering shrinkage than oxide ceramics, and have an oxidation temperature in the atmosphere of 1000 ° C. or higher and are oxidized after oxidation. It is preferable to use a ceramic that does not decompose or evaporate. Specifically, nitrides such as Si ₃ N ₄ , AlN, and BN, carbides such as SiC, B ₄ C, and WC, and aluminides such as CrAl can be used as the hardly sintered material. Among these, it is particularly preferable to use SiC that is preferably used as a material for CMC. In addition, about the shape and particle size of a difficult-to-sinter material with small sintering shrinkage, it is not particularly limited as long as it is smaller than the size of the pores 1b of the substrate 1, but those having an average particle size of about 1 to 10 μm. It can be preferably used.

As shown in FIG. 1, a coating layer 5 is formed on the surface to be coated 1 a of the substrate 1 with an intermediate layer 3 interposed therebetween. The coating layer 5 is preferably formed of HfO ₂ having excellent heat resistance and environmental resistance.

The ceramic matrix composite member 10 shown in FIG. 1 can be manufactured by the following method.
"Relaxation layer formation process"
In the present embodiment, the case where the intermediate layer 3 is formed simultaneously with the formation of the stress relaxation layer 2 will be described as an example. First, the slurry containing the stress relaxation material is filled in at least the pores 1b exposed on the coating surface 1a by impregnating the coated surface 1a of the base material 1 with the slurry containing the stress relaxation material. The impregnation here is preferably performed, for example, by burying the base material 1 in the raw material powder precipitated in the dispersion medium in the slurry and applying vibration to the slurry and the base material using ultrasonic waves. Thus, by impregnating the pores 1b with the slurry, the raw material powder can be impregnated at a high concentration in the pores 1b of the substrate 1. Alternatively, the base material 1 is immersed in a slurry in which the raw material powder is uniformly dispersed in the dispersion medium, the pressure is reduced, the atmosphere is deaerated from the pores in the base material 1, and the slurry is replaced with the base material. The raw material powder can be impregnated into one pore 1b. Further, when the pores 1b of the substrate 1 are continuous pores from the coated surface 1a to the other surface, a slurry in which the raw material powder is uniformly dispersed in the dispersion medium is pressurized and injected from the coated surface 1a. Alternatively, the pores 1b can be impregnated with the slurry by reducing the pressure from a surface other than the coated surface 1a. In this method, the coated surface 1a and the surface other than the coated surface 1a may be reversed.
Next, the slurry is applied to the surface to be coated 1a by dipping, and a film is appropriately formed on the surface and dried. This dipping and drying can be appropriately repeated according to the thickness of the intermediate layer 3 and the like. Moreover, the slurry used in dipping may be the same as or different from the slurry used at the time of impregnation.

As the slurry used for dipping and impregnation, a slurry composed of a raw material powder and a dispersion medium is used. As the raw material powder, it is preferable to use a raw material powder containing a base material that becomes oxide ceramics by sintering and a hardly sintered material having sintering shrinkage smaller than that of oxide ceramics. Furthermore, a sintering aid can be added to the raw material powder as necessary.
As the base material, Yb ₂ O ₃ powder, Y ₂ O ₃ powder, Er ₂ O ₃ powder, Al ₂ O ₃ powder, SiO ₂ powder, MgO powder, borosilicate glass powder, and the like are used. In addition, SiC powder, Si ₃ N ₄ powder, AlN powder, BN powder, B ₄ C powder, CrAl powder, WC powder, CrAl powder, etc. are used as difficult-to-sinter materials having smaller sintering shrinkage than oxide ceramics. It is done. In addition, borosilicate glass powder or the like is used as a sintering aid.
Moreover, as the dispersion medium, it is preferable to use a dispersion medium including a dispersion medium composed of a sol that contributes to an oxidation reaction during sintering and a solvent for adjusting the viscosity of the slurry.
As the sol, silica sol, alumina sol or the like is used. As the solvent, ethanol or the like is used.

When a slurry composed of the raw material powder and the dispersion medium is used as a slurry used for dipping and impregnation, it is included in the SiO ₂ contained in the sol or the sol and the sintering aid by performing sintering. SiO ₂ reacts with the base material element to become oxide ceramics constituting the stress relaxation layer 2 and the intermediate layer 3, and at the same time, the raw material powders are bonded to each other. The mixing ratio of the raw material powder and the dispersion medium can be appropriately determined in consideration of the workability during impregnation, the number of dipping times, the thickness of the intermediate layer 3 to be finally obtained, and the like.

  Further, the volume ratio of the hardly sintered material in the raw material powder in the slurry is preferably in the range of 30% to 90%, and more preferably in the range of 40% to 60%. If the volume ratio of the hard-to-sinter material in the raw material powder in the slurry is less than the above range, cracking may occur in the intermediate layer 3 due to excessive shrinkage due to sintering when the intermediate layer 3 is formed, or the intermediate layer 3 May peel off, and the adhesive force between the coating layer 5 and the substrate 1 may not be sufficiently increased. When the volume ratio of the hard-to-sinter material in the raw material powder in the slurry exceeds the above range, the bond strength obtained by sintering for forming the intermediate layer 3 becomes insufficient, and the intermediate layer 3 having sufficient hardness. May not be obtained.

  Next, the slurry adhered to the base material 1 is sintered in an argon atmosphere at a temperature of 1300 ° C. for about 1 hour, so that the pores filled with the slurry are made into the filled pores 1b filled with the stress relaxation material. The relaxation layer 2 is formed, and the intermediate layer 3 continuously integrated with the stress relaxation layer 2 is formed. The sintering here is preferably performed at a temperature of 1300 ° C. or lower so as not to adversely affect the strength of the substrate 1.

"Coating process"
After the relaxation layer forming step, a ceramic layer composite member 10 shown in FIG. 1 is obtained by forming a coating layer on the intermediate layer 3 by APS (air spraying in the atmosphere).

In the ceramic matrix composite member 10 of the present embodiment, at least one of the plurality of pores of the substrate 1 exposed to the coated surface 1a is a filled pore 1b filled with a stress relaxation material. Since the thermal expansion coefficient of the material is a value between the base material 1 and the coating layer 5, the filling surface 1 a and the filling pores 1 b existing at the deepest position from the coating surface 1 a among the filling pores 1 b are filled. Since the stress relaxation layer 2 is between the formed stress relaxation material, the stress relaxation layer 2 reduces the residual stress accompanying the thermal expansion difference due to the difference in thermal expansion coefficient between the coating layer 5 and the substrate 1. The adhesion between the coating layer 5 and the substrate 1 can be improved.
Moreover, in the ceramic matrix composite member 10 of the present embodiment, the stress relaxation layer 2 is such that at least the pores exposed to the coated surface 1a among the plurality of pores of the substrate 1 are filled pores 1b. The anchoring effect for improving the adhesion between the coating layer 5 and the substrate 1 can be effectively obtained by the stress relaxation layer 2, and the physical adhesive force between the coating layer 5 and the substrate 1 can be enhanced.

On the other hand, for example, when the coating layer made of HfO ₂ is formed on the base made of CMC without forming the stress relaxation layer 2 and the intermediate layer 3, the thermal expansion coefficient of HfO ₂ is 9.3 [× so high as 10 ^-6 / K], the difference in thermal expansion coefficient between the substrate 1 the thermal expansion coefficient of about 3 [× 10 ^-6 / K] becomes very large. Therefore, when the coating layer in contact with the substrate is formed on the substrate, it is difficult to sufficiently increase the adhesion between the coating layer and the substrate.

  Further, in the ceramic matrix composite member 10 of the present embodiment, the stress relaxation layer 2 provides an anchoring effect that improves the adhesion between the coating layer 5 and the substrate 1, so that the oxide ceramics alone can relieve stress. Even in the case of oxide ceramics with weak adhesion that cannot form the layer 2 and the intermediate layer 3, it is possible to form the stress relaxation layer 2 and the intermediate layer 3 with high adhesion.

  In addition, the stress relaxation layer 2 and the intermediate layer 3 gradually sinter and shrink due to use in a high temperature environment, resulting in a decrease in adhesion and peeling. In the ceramic matrix composite member 10 of the present embodiment, the sintering shrinkage of the stress relaxation layer 2 and the intermediate layer 3 in a high temperature environment is prevented by the filled pores 1b and the CMC constituting the stress relaxation layer 2. As a result, the rate of sintering shrinkage of the stress relaxation layer 2 and the intermediate layer 3 can be reduced, and the life until the stress relaxation layer 2 and the intermediate layer 3 are peeled can be extended by slowing down the adhesion force. it can.

  Further, in the ceramic matrix composite member 10 of the present embodiment, the stress relaxation layer 2 is such that pores exposed at least on the coated surface 1a among the plurality of pores of the substrate 1 are filled pores 1b. Even if oxygen or water vapor enters through the coating layer 5, since the pores exposed on the surface to be coated 1a serving as a diffusion path of the oxygen and water vapor that has entered therein are filled with the stress relaxation material, Contact between water vapor and the substrate 1 can be prevented. Therefore, deterioration of the base material 1 can be prevented, and the ceramic base composite member 10 having a long life is obtained.

  Further, in the ceramic matrix composite member 10 of the present embodiment, since the ratio of the filled pores 1b in the stress relaxation layer 2 increases as it approaches the coating layer 5, the thermal expansion coefficient of the stress relaxation layer 2 is increased. The value is gradually close to the coefficient of thermal expansion of the base material 1 as the distance from the center is increased. That is, in the ceramic matrix composite member 10 of the present embodiment, the thermal expansion coefficient is changed in a stepwise manner between the coating layer 5 and the substrate 1, and between the coating layer 5 and the substrate 1. A thermal stress can be relieved effectively and the adhesive force between the coating layer 5 and the base material 1 can be improved effectively.

  In the ceramic matrix composite member 10 of this embodiment, the intermediate layer 3 made of a stress relaxation material and integrated with the stress relaxation layer 2 is provided between the stress relaxation layer 2 and the coating layer 5. 5 and the base material 1 can be further relaxed, and the adhesion between the coating layer 5 and the base material 1 can be further effectively improved.

Further, in the ceramic matrix composite member 10 of the present embodiment, the stress relaxation material includes an oxide ceramic and a hard-to-sinter material whose sintering shrinkage is smaller than that of the oxide ceramic. The adhesion between the coating layer 5 and the substrate 1 can be further effectively improved.
Here, for example, a case where an intermediate layer made only of oxide ceramics is formed on a substrate by a sintering method will be described with reference to the drawings for volume shrinkage of the intermediate layer during sintering. FIG. 3 is a schematic diagram for explaining volume shrinkage due to sintering of oxide ceramics constituting the intermediate layer. FIG. 3A is a diagram showing a state of oxide ceramics before sintering, and FIG. 3B is a diagram showing a state of oxide ceramics after sintering.

As shown in FIGS. 3A and 3B, when the oxide ceramics 17 before sintering and the oxide ceramics 17a after sintering are compared, the oxide ceramics 17a after sintering are adjacent to each other. It can be seen that the proportion of the gap 8 between the ceramic materials 17a is narrow, and the volume is greatly contracted by sintering.
For this reason, when an intermediate layer made only of oxide ceramics is formed on a substrate by a sintering method, the intermediate layer may peel off from the substrate due to large volume shrinkage of the oxide ceramics during sintering. It was. Moreover, in order to avoid volumetric shrinkage of the oxide ceramics during the sintering of the intermediate layer, an intermediate layer made only of the oxide ceramics can be formed on the substrate by a thermal spraying method. However, in this case, fine cracks and fine particles are present in the obtained intermediate layer. Therefore, when the ceramic matrix composite member is exposed to heat for the first time, the material constituting the intermediate layer is sintered, and a large volume shrinkage occurs due to the sintering, so that the intermediate layer may be peeled off from the base material.

  On the other hand, with reference to the drawings, the volumetric shrinkage of the stress relaxation material during sintering when the stress relaxation material includes an oxide ceramic and a hard-to-sinter material having a smaller sintering shrinkage than the oxide ceramic. To do. FIG. 4 is a schematic diagram for explaining volume shrinkage due to sintering of the stress relaxation material. FIG. 4A is a diagram showing a state of the stress relaxation material before sintering, and FIG. 4B is a diagram showing a state of the stress relaxation material after sintering.

As shown in FIG. 4A and FIG. 4B, when the oxide ceramics 7 before sintering and the oxide ceramics 7a after sintering are compared, the oxide ceramics 7a after sintering are adjacent to each other. The ratio of the gap 8 between the ceramic materials 7a is narrow. However, between the sintered oxide ceramics 7a shown in FIG. 4 (b), the proportion of the gap 8 is larger than that between the sintered oxide ceramics 17a shown in FIG. 3 (b). ing. Moreover, in the oxide ceramics 7a after sintering shown in FIG. 4B, the hardly-sinterable material 6 whose sintering shrinkage is smaller than that of the oxide ceramics partially enters between the oxide ceramics 7a and is sintered. It can be seen that the shrinkage due to squeezing is prevented, and the volumetric shrinkage of the stress relaxation material due to sintering is relaxed.
As described above, the stress relaxation material includes the oxide ceramic and the hardly sintered material whose sintering shrinkage is smaller than that of the oxide ceramic, so that the stress relaxation layer 2 and the intermediate layer 3 are sintered or exposed to heat. Volume shrinkage can be reduced, and peeling of the stress relaxation layer 2 and the intermediate layer 3 can be prevented, so that the adhesion between the coating layer 5 and the substrate 1 can be more effectively improved. Can do.

Further, when SiC is a hard-to-sinter material whose sintering shrinkage is smaller than that of oxide ceramics contained in the stress relaxation material, the thermal expansion coefficient of SiC and the thermal expansion coefficient of CMC constituting the substrate 1 are approximated. The adhesion between the substrate 1 and the stress relaxation layer 2 and the intermediate layer 3 can be further improved, and the adhesion between the coating layer 5 and the substrate 1 can be effectively improved.
Further, in the ceramic matrix composite member 10 of the present embodiment, when the hard-to-sinter material included in the stress relaxation material is SiC and the ceramic fiber and / or ceramic matrix is made of SiC, the thermal expansion coefficient of SiC And the thermal expansion coefficient of the CMC constituting the base material 1 are very close to each other, so that the adhesion between the base material 1 and the stress relaxation layer 2 and the intermediate layer 3 can be further improved. The adhesion force between the material 1 can be improved more effectively.

When the ceramic fiber and / or the ceramic matrix is made of SiC, SiC constituting the substrate 1 is oxidized and changed to SiO ₂ in high-temperature air. Then, during or during pressurized圧大air atmospheric pressure, the SiO ₂ is formed on the surface of the SiC constituting the substrate 1, SiO ₂ serves as a protective layer, oxidation of the additional SiC is suppressed. However, if water vapor is contained in the atmosphere, SiO ₂ constituting the protective layer evaporates as SiO. For this reason, the protective layer made of SiO ₂ disappears, further oxidation of SiC proceeds, and SiO ₂ is further formed and evaporated as SiO. As a result, the CMC constituting the substrate 1 is thinned. Therefore, when CMC using SiC is used in a part exposed to a high-temperature atmospheric environment containing water vapor such as a gas turbine, it is necessary to suppress the progress of SiC oxidation and to reduce CMC thinning due to water vapor. There is.

Here, when using a material including SiC and a rare earth silicate such as Yb ₂ SiO ₅ , Y ₂ SiO ₅ , Er ₂ SiO ₅ as the stress relaxation material constituting the stress relaxation layer 2 and the intermediate layer 3, The SiC contained in the stress relaxation layer 2 and the intermediate layer 3 is gradually oxidized to SiO ₂ by use in a high-temperature oxidation environment for a long time. SiO ₂ of SiC is obtained by being oxidized _{by Yb 2 SiO 5, Y 2 SiO} 5, Er 2 SiO 5 is changed to _{Yb 2 Si2O 7, Y 2 Si2O} 7, Er 2 Si2O 7 respectively, rare earth silicates It is absorbed into and integrated with the rare earth silicate. Therefore, it is possible to prevent the CMC constituting the base material 1 from being thinned by evaporating SiO ₂ as SiO.

In addition, when a material containing SiC and a rare earth silicate such as Yb ₂ SiO ₅ , Y ₂ SiO ₅ , Er ₂ SiO ₅ is used as the stress relaxing material constituting the stress relaxing layer 2 and the intermediate layer 3, When SiC is oxidized to SiO ₂ by use in a high-temperature oxidizing environment for a long time, the volume expands. On the other hand, the sintering shrinkage of the rare earth silicate contained in the stress relaxation layer 2 and the intermediate layer 3 gradually progresses due to the use in a high temperature oxidation environment for a long time. Therefore, the volume expansion due to the change of SiC to SiO ₂ is offset by the sintering shrinkage of the rare earth silicate, contributing to the suppression of the volume shrinkage of the stress relaxation layer 2 and the intermediate layer 3 as a whole, and high-temperature oxidation for a long time. Adverse effects such as a decrease in adhesion due to volumetric shrinkage that gradually proceeds due to use in the environment can be prevented, and the life can be extended.
Moreover, the ceramic-based composite member 10 is used in a portion exposed to a high-temperature atmospheric environment containing water vapor by including a rare earth silicate such as Yb ₂ SiO ₅ , Y ₂ SiO ₅ , Er ₂ SiO ₅ as the stress relaxation material. Even in this case, the stress relaxation layer 2 and the intermediate layer 3 are difficult to be decomposed and have excellent heat resistance and environmental resistance.

Moreover, in the ceramic matrix composite member 10 of the present embodiment, the stress relaxation material contains SiC and Yb ₂ SiO ₅ , so that the stress relaxation layer 2 and the intermediate layer 3 have excellent heat resistance and environmental resistance, and gas There is little deterioration in a high-temperature gas environment such as a turbine, the adhesion force can be maintained for a long time, and the life is long. Further, by including SiC and Yb ₂ SiO ₅ as the stress relaxation material, the stress relaxation layer 2 and the intermediate layer 3 become denser than the coating layer 5 made of HfO ₂ formed by APS (air spraying in the atmosphere). . Therefore, even if high-temperature oxidation / corrosion gas such as water vapor enters through the coating layer 5, the substrate 1 can be effectively suppressed from being exposed to the high-temperature oxidation / corrosion gas. It is possible to prevent a decrease in strength.

Moreover, in the ceramic matrix composite member 10 of the present embodiment, the ceramic matrix composite member 10 having excellent heat resistance and environmental resistance is obtained by forming the coating layer 5 from HfO ₂ .

  Note that the method of forming the stress relaxation layer 2 and the intermediate layer 3 is not limited to the above method, and thermal spraying, sintering, CVD, PVD, dipping of molten glass, etc., depending on the material of the stress relaxation material. Can be used in appropriate combinations.

Further, in the ceramic matrix composite member 10 of the present embodiment, by providing a groove or the like on the coated surface 1a of the substrate 1, it is possible to improve the adhesion of the coated surface 1a of the substrate 1, A sufficiently high adhesion force between the coating layer 5 and the substrate 1 can be obtained, but a groove may be provided in the coated surface 1a of the substrate 1 to further improve the adhesion force.
In the present invention, as described above, it is preferable to provide the stress relaxation layer 2 and the intermediate layer 3 made of the stress relaxation material, but the intermediate layer 3 may not be provided.

Further, the coating layer 5 is not limited to HfO ₂ , and for example, oxide ceramics such as Lu ₂ Si ₂ O ₇ having high heat resistance, oxidation resistance, corrosion resistance, and free-cutting property against a high temperature gas environment. Etc. can be used. Moreover, as a formation method of the coating layer 5, in addition to thermal spraying, sintering, CVD, PVD, dipping of molten glass, or the like can be used, and can be appropriately determined according to the material of the coating layer.

(Example)
Next, examples of the present invention will be described.
"Experiment 1"
A stress relaxation layer and an intermediate layer were formed on the substrate according to the flowchart shown in FIG.
That is, the coated surface 1a of the substrate 1 shown below was impregnated for 10 minutes in a slurry obtained by the raw materials and manufacturing method shown below (S1 shown in FIG. 5). In the impregnation of the base material 1, the base material 1 is embedded in the raw material powder precipitated in the dispersion medium contained in the slurry, and the container containing the slurry and the base material 1 is placed in an ultrasonic cleaner, and the base material 1 and The slurry was vibrated, the substrate 1 was impregnated with the slurry, and the pores 1b were filled with the raw material powder. Next, the excess slurry stuck to the base material 1 is removed (S2 shown in FIG. 5), the raw material powder precipitated in the dispersion medium of the slurry is scooped up and placed on the coated surface 1a of the base material 1 and applied ( S3) shown in FIG. 5 was performed. Then, it dried in air | atmosphere for 20 minutes at 100 degreeC (S4 shown in FIG. 5), and formed the membrane | film | coat on the to-be-coated surface 1a. Next, the slurry adhered to the substrate 1 is sintered in an argon atmosphere at a temperature of 1300 ° C. for about 1 hour (S5 shown in FIG. 5), so that the stress relaxation layer 2 having a thickness of 4 mm and an intermediate thickness of 0.15 mm are obtained. Layer 3 was formed.

"Base material"
Material: Ceramic matrix composite material consisting of ceramic fiber made of 3D reinforced SiC long fiber and ceramic matrix made of SiC Porosity: about 40%
Dimensions: 10mm long, 10mm wide, 4mm thick

"slurry"
A powder composed of 3.35 g of SiC powder, 3.78 g of Yb ₂ O ₃ powder, 0.89 g of borosilicate glass powder, 1 ml of silica sol, and 1 ml of ethanol was used.
(material)
SiC powder: Average particle size of about 4 μm, Showa Denko KK, Green Densick (trade name)
Yb ₂ O ₃ powder: average particle size of about 1 μm, borosilicate glass (Pyrex glass: trade name (registered trademark)) manufactured by Shin-Etsu Chemical Co., Ltd. powder: 200 mesh, manufactured by Furuuchi Chemical Co., Ltd. silica sol: particle size of 10-20 nm, Made by Nissan Chemical Industries, Snowtex (trade name)
Ethanol: purity 99.5%, Showa Chemical Co., Ltd.

(Slurry production method)
First, a predetermined amount of raw material powder composed of SiC powder, Yb ₂ O ₃ powder and borosilicate glass powder was measured and mixed. By setting the raw material to the above mixing ratio, the volume ratio of the SiC powder in the raw material powder becomes 50%. That is, the volume ratio of SiC powder is 50%, and the total volume ratio of Yb ₂ O ₃ powder and borosilicate glass powder is 50%. Further, the amount of Yb ₂ O ₃ powder, borosilicate glass powder, and silica sol in the dispersion medium is such that SiO ₂ contained in the borosilicate glass powder and silica sol reacts with Yb ₂ O ₃ to yield Yb ₂ SiO _5. It adjusted so that it might become quantity.
Next, a predetermined amount of silica sol and ethanol were measured and mixed to obtain a dispersion medium. Next, the raw material powder and the dispersion medium were mixed to form a slurry.

  Thus, the base material 1 in which the stress relaxation layer 2 and the intermediate layer 3 were formed was observed. As a result, the intermediate layer was fixed on the base material, and did not peel off, and no cracks were generated.

FIG. 6A is a photomicrograph of a cross section of the substrate 1 on which the stress relaxation layer 2 and the intermediate layer 3 are formed. 6 (b) and 6 (c) are photomicrographs showing an enlarged part of FIG. 6 (a), and FIG. 6 (b) is a photomicrograph of the stress relaxation layer 2, FIG. 6 (c) is a photomicrograph of the vicinity of the coated surface 1 a of the substrate 1.
From FIG. 6A and FIG. 6B, the pores exposed on the coated surface 1a of the substrate 1 are filled with the stress relaxation material SiC and Yb ₂ SiO ₅ to form the stress relaxation layer 2. It turns out that it is set as the filling pore 1b. Further, FIG. 6A shows that an intermediate layer 3 made of SiC and Yb ₂ SiO _{5 as} stress relaxation materials is formed on the stress relaxation layer 2. Further, in FIG. 6 (c), the dark portion of the stress relaxation material constituting the intermediate layer 3 is _Yb 2 SiO _5, the bright portion is SiC, and the SiC and _Yb 2 SiO ₅ are uniformly dispersed I understand that.

"Experimental example 2"
A base material 1 having a stress relaxation layer 2 and an intermediate layer 3 obtained in the same manner as in Experimental Example 1 is prepared, and a coating layer having a thickness of 70 mm made of HfO ₂ is formed on the intermediate layer 3 by APS (air spray). 5 was obtained, and the ceramic matrix composite member 10 shown in FIG. 1 was obtained.
The result is shown in FIG. FIG. 7 is a photograph of the ceramic matrix composite member of Experimental Example 2. As shown in FIG. 7, no crack was generated in the coating layer 5, and it was confirmed that the coating layer 5 and the substrate 1 had sufficient adhesion.

"Experiment 3"
In order to determine a preferable volume ratio of the SiC powder in the raw material powder in the slurry, the following experiment was performed.
(Sample 1 to Sample 10)
In order to clarify the sintering shrinkage of the intermediate layer 3 using the formulation shown in Table 1 as the slurry, the thickness of the slurry to be placed on the coated surface 1a of the substrate 1 at the time of application is 1 mm thicker than usual. Except for the above, a substrate 1 having a stress relaxation layer 2 having a thickness of 4 mm and an intermediate layer 3 having a thickness of 1 mm was obtained in the same manner as in Experimental Example 1.
In addition, when the raw material powder and the dispersion medium are mixed and the dispersion medium is small and does not have fluidity, ethanol is added as appropriate to obtain a fluid liquid.
Moreover, since the intermediate layer 3 was thick and dried rapidly, the intermediate layer 3 was cracked in all samples after drying and before sintering.

  About the base material 1 in which the stress relaxation layer 2 and the intermediate layer 3 of Sample 1 to Sample 10 thus obtained were formed, cracks and hardness were evaluated based on the following evaluation criteria, and from the results Comprehensive evaluation was performed as shown below. The results are shown in Table 1.

"Crack"
○: After firing, there was no spread of cracks that were dry, and new cracks that were not dry were not seen. △: After firing, the width of cracks that were dry was somewhat widened, but dried. There were no new cracks that sometimes did not.
X: After firing, the width of cracks that were present during drying widened, and cracks that were not present during drying occurred.

"Hardness"
○: The hardness is such that the surface cannot be shaved with a nail.
(Triangle | delta): It is the hardness of the grade which can scrape off the surface with a nail.
X: The predetermined shape as an intermediate layer cannot be maintained.

"Comprehensive"
◯: Both crack and hardness evaluations are ◯.
Δ: Either one of crack and hardness evaluation is Δ, and the other is ○.
X: Either crack or hardness evaluation is x.

  Moreover, the photograph of the base material 1 in which the stress relaxation layer 2 and the intermediate | middle layer 3 were formed is shown in FIGS. 8 (a) is a photograph of sample 1, FIG. 8 (b) is a photograph of sample 2, FIG. 8 (c) is a photograph of sample 3, FIG. 9 (a) is a photograph of sample 4, and FIG. 9 (b) is a photograph. 10A is a photograph of sample 6, FIG. 10B is a photograph of sample 7, FIG. 11A is a photograph of sample 8, FIG. 11B is a photograph of sample 9, and FIG. 11 (c) is a photograph of Sample 10.

As shown in FIGS. 8 to 11, in all the samples, the intermediate layer was fixed on the base material and did not peel off.
From Table 1, the evaluation of cracks for Sample 1 to Sample 3 was x. This is considered to be because the shrinkage of sintering was large in Samples 1 to 3 because the SiC mixing amount was small.
Further, for sample 4, the evaluation of the crack was Δ, and for samples 5 to 10, the evaluation of the crack was ○. As a result, it is considered that sintering shrinkage was suppressed for Samples 4 to 10 in which SiC was mixed by 40% or more.

Moreover, from Table 1, the evaluation of hardness of Sample 1 to Sample 7 was “◯”, and that of Sample 8 to Sample 10 was “Δ”. Since Samples 8 to 10 have a large SiC mixing amount of 70% or more, the bonding strength due to sintering of the Yb ₂ SiO ₅ powder was weakened, and it was considered that only a hardness that could be scraped with a nail was obtained.
However, even in the sample 10 in which the SiC mixing amount is 90%, the predetermined shape as the intermediate layer is maintained, and the bonding between the powders is not so weak that it breaks when touched. From this, it is considered that the sample 10 is also bonded to the powder by sintering the Yb ₂ SiO ₅ powder.

  From the above results, the preferred volume ratio of the SiC powder in the raw material powder in the slurry is 30 to 90%, and in the range of 40 to 60%, the volume shrinkage is small, and a hard intermediate layer is obtained. It turned out to be more preferable.

"Experimental example 4"
Except that the base material 1 was not immersed in the slurry and the raw material powder precipitated in the dispersion medium of the slurry was applied to the coated surface 1a of the base material 1 and applied, the same as in Experimental Example 1. The base material 1 in which the intermediate layer was formed was obtained.
Thus, the base material 1 of Experimental Example 4 in which the intermediate layer was formed was observed. As a result, many cracks were generated in the intermediate layer or between the substrate 1 and the intermediate layer, and there were portions where the intermediate layer was peeled off from the substrate.

“Experimental Example 5”
A stress relaxation layer and an intermediate layer were formed on the substrate according to the flowchart shown in FIG.
That is, as shown below, the surface to be coated 1a of the base material 1 made of samples A and B having different shapes is impregnated in the following impregnation slurry in the same manner as in Experimental Example 1 (S1 shown in FIG. 12). ), And excess slurry stuck to the base material 1 was dropped in the same manner as in Experimental Example 1 (S2 shown in FIG. 12). Subsequently, it was dried in the air at room temperature for 10 minutes and in the air at 100 ° C. for 20 minutes (S41 shown in FIG. 12). Next, dipping (S32 shown in FIG. 12) was performed by dipping in the dipping slurry shown below and applying the dipping slurry to the surface to be coated 1a.

Then, the base material 1 is installed in a state where the contact between the base material 1 and the floor surface or the wall surface is reduced as much as possible so that the dipping slurry naturally flows down from the surface of the base material 1. For 20 minutes in air at 100 ° C. for 20 minutes (S41 shown in FIG. 12). As a result, the raw material powder contained in the dipping slurry was thinly adhered to the surface of the substrate 1. Thereafter, as shown in FIG. 12, dipping S32 and drying S41 were repeated until the weight of the raw material powder in the slurry adhering to the substrate 1 reached a predetermined weight. In addition, at the time of the second and subsequent drying, the vertical direction of the base material 1 was reversed and installed in the previous drying so that the coating thickness of the dipping slurry was uniform.
Thereafter, sintering (S5 shown in FIG. 12) was performed in the same manner as in Experimental Example 1 to form a stress relaxation layer 2 having a thickness of 4 mm and an intermediate layer 3 having a thickness of 10 to 30 μm.

"Base material"
Material: Ceramic matrix composite material consisting of ceramic fiber made of 3D reinforced SiC long fiber and ceramic matrix made of SiC Porosity: about 10%
Dimensions: Length 3mm, width 4mm, height 45mm (sample A)
Length 35mm, width 50mm, thickness 3mm (sample B)

"Slurry for impregnation"
The same raw materials as in Experimental Example 1 were used, and the same raw material as in Experimental Example 1 was produced. The formulation is shown below.
A powder composed of 17.76 g of SiC powder, 32.25 g of Yb ₂ O ₃ powder, 3.99 g of borosilicate glass powder, 4.8 ml of silica sol, and 4.8 ml of ethanol was used.

"Slipping slurry"
The same raw material as in Experimental Example 1 was used. The formulation is shown below.
A powder composed of 17.76 g of SiC powder, 32.25 g of Yb ₂ O ₃ powder, 3.99 g of borosilicate glass powder, 12.2 ml of silica sol, and 12.2 ml of ethanol was used.
(Method for producing slurry for dipping)
First, a predetermined amount of raw material powder composed of SiC powder, Yb ₂ O ₃ powder and borosilicate glass powder was measured and mixed. By setting the raw material to the above mixing ratio, the volume ratio of the raw material powder in the dipping slurry becomes 30%. Next, a predetermined amount of silica sol and ethanol were weighed and mixed to obtain a dispersion medium. Next, the raw material powder and the dispersion medium were mixed so as to eliminate the precipitation of the raw material powder to obtain a dipping slurry.

  The base material 1 on which the stress relaxation layer 2 and the intermediate layer 3 thus obtained were observed was observed. The result is shown in FIG. FIG. 13 is a photograph of the base material on which the stress relaxation layer and intermediate layer of Experimental Example 5 were formed. 13A is a photograph of the base material of sample A, and FIG. 13B is a photograph of the base material of sample B. As shown in FIGS. 13 (a) and 13 (b), both the sample A and the sample B have a stress relaxation material in pores existing between the textures of the ceramic fibers exposed on the surface of the CMC constituting the substrate. It was confirmed that it was filled. In both Sample A and Sample B, the intermediate layer was fixed on the base material, and did not peel off, and no cracks were generated.

"Oxidation resistance test"
The substrate 1 on which the stress relaxation layer 2 and the intermediate layer 3 thus obtained were formed was exposed to the atmosphere at 1300 ° C. for 100 hours, and the change in appearance was confirmed.
As a result, in both sample A and sample B, the intermediate layer was fixed on the substrate, and did not peel off, and no cracks were generated. Further, in both sample A and sample B, the intermediate layer 3 which was light green changed to white. This is presumably because part or all of the green SiC was oxidized and changed to white or transparent SiO ₂ by the oxidation resistance test.

"Water vapor resistance test"
In addition, the APS (atmospheric spraying) onto the intermediate layer 3 of the substrate 1 to form a coating layer consisting of _Lu 2 _Si 2 _{O 7,} to obtain a ceramic-based composite member 10 shown in FIG. The ceramic matrix composite member 10 thus obtained was exposed to the atmosphere of 1300 ° C., a total pressure of 9.5 atm, and a water vapor partial pressure of 1.5 atm for 2000 hours, and its appearance change was confirmed.
As a result, neither sample A nor sample B was observed to be peeled off or cracked from the coating layer 5.
Here, since the coating layer 5 made of Lu ₂ Si ₂ O ₇ transmits oxygen at a high temperature, the stress relaxation layer 2 and the intermediate layer 3 arranged under the coating layer 5 are used in the water vapor resistance test. Similarly to the oxidation resistance test, it is considered that part or all of SiC is oxidized and changed to SiO ₂ . Therefore, even if SiC contained in the stress relaxation layer 2 and the intermediate layer 3 is oxidized by the water vapor resistance test, the coating layer 5 is not peeled off or cracked. From this, the stress relaxation layer 2 and the intermediate layer 3 do not cause excessive shrinkage or expansion that lowers the adhesion strength of the coating layer 5 by the water vapor resistance test, and the CMC and coating constituting the substrate 1. It was confirmed that no chemical reaction that would reduce the strength of the layer 5 occurred.

  From the results of the oxidation resistance test and the steam resistance test, it can be confirmed that the adhesion force between the substrate 1 and the coating layer 5 can be sufficiently obtained by providing the stress relaxation layer 2 and the intermediate layer 3 of Experimental Example 5. It was.

"Experimental example 6"
(Sample 11 to Sample 24)
The thickness of the slurry to be placed on the coated surface 1a of the substrate 1 at the time of dipping in order to clarify the sintering shrinkage of the intermediate layer 3 using the composition shown in Table 2 consisting of the following materials as the slurry The substrate 1 on which the stress relaxation layer 2 having a thickness of 4 mm and the intermediate layer 3 having a thickness of 1 mm were formed was obtained in the same manner as in Experimental Example 1 except that the thickness was set to 1 mm thicker than usual.
In the formulation shown in Table 2, the volume ratio of the hardly sintered material powder in the raw material powder is 50%. In addition, when the raw material powder and the dispersion medium are mixed, if the dispersion medium is small and does not have fluidity, ethanol is added as appropriate to obtain a fluid liquid. In addition, when WC was used as the hardly sintered material and when CrAl was used, the sintering temperature was set to 1000 ° C. because the decomposition temperature of the hardly sintered material was low.
Moreover, since the intermediate layer 3 was thick and dried rapidly, the intermediate layer 3 was cracked in all samples after drying and before sintering.

"slurry"
(material)
SiC powder: Average particle size of about 4 μm, Showa Denko KK, Green Densick (trade name)
Si ₃ N ₄ powder (1): average particle size of about 1 μm, manufactured by Ube Industries, SN-E10 (trade name)
Si ₃ N ₄ powder (10): average particle size of about 10 μm, manufactured by Ube Industries, SN-E01 (trade name)
AlN powder: average particle diameter of about 5 μm, Furukawa Electronics Co., Ltd., FAN-f05 (trade name)
BN powder: average particle size of about 7 μm, manufactured by Denki Kagaku Kogyo Co., Ltd., AP650 (trade name)
B ₄ C powder: average particle diameter of about 2.5 μm, HC Starck GRADE HP
WC powder: average particle size about 5μm, in-house adjusted powder CrAl powder: average particle size about 5μm, in-house adjusted powder

Yb ₂ O ₃ powder: average particle size of about 1 μm, Shin-Etsu Chemical Co., Ltd. Y ₂ O ₃ powder: average particle size of about 1 μm, Shin-Etsu Chemical Co., Ltd. Er ₂ O ₃ powder: average particle size of about 1 μm, Shin-Etsu Chemical Al ₂ O ₃ powder manufactured by Kogyo Co., Ltd .: average particle size of about 0.3 μm, manufactured by Sumitomo Chemical Co., Ltd., AKP50 (trade name)
SiO ₂ powder: average particle size of about 6 μm, manufactured by Denki Kagaku Kogyo Co., Ltd., fused silica FS-30 (trade name)
MgO powder: average particle size of about 1 μm, manufactured by Soekawa Riken

Borosilicate glass powder (Pyrex glass: trade name (registered trademark)): 200 mesh, manufactured by Furuuchi Chemical Co., Ltd. Silica sol: particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Snowtex (trade name)
Alumina sol: manufactured by Nissan Chemical Industries, Ltd., Alumina sol 100 (trade name)
Ethanol: purity 99.5%, Showa Chemical Co., Ltd.

  The base material 1 on which the stress relaxation layer 2 and the intermediate layer 3 of Samples 11 to 24 thus obtained were formed was evaluated for hardness in the same manner as in Experimental Example 3. The results are shown in Table 2.

  Moreover, the photograph of the base material 1 in which the stress relaxation layer 2 and the intermediate | middle layer 3 were formed is shown in FIGS. 14 (a) is a photograph of sample 11, FIG. 14 (b) is a photograph of sample 12, FIG. 14 (c) is a photograph of sample 13, FIG. 15 (a) is a photograph of sample 14, and FIG. FIG. 15 (c) is a photograph of sample 16, FIG. 16 (a) is a photograph of sample 17, FIG. 16 (b) is a photograph of sample 18, FIG. 17 (a) is a photograph of sample 19, and FIG. 17 (b) is a photograph of sample 20, FIG. 18 (a) is a photograph of sample 21, FIG. 18 (b) is a photograph of sample 22, FIG. 19 (a) is a photograph of sample 23, and FIG. 19 (b) is a sample. It is 24 photographs.

  As shown in FIGS. 14 to 19, in all the samples, the intermediate layer was fixed on the base material and did not peel off. Further, after firing, there was no broadening of the crack width that was present during drying and no new cracks that were not present during drying. In addition, the bond between the powders is weak and does not break when touched.

Moreover, from Table 2, the evaluation of hardness was “good” in sample 12, sample 13, sample 15 to sample 20, and sample 22 to sample 24, and “Δ” in sample 11, sample 14, and sample 21.
In Sample 11, Sample 14, and Sample 21, whose hardness was evaluated as Δ, it was necessary to add ethanol to form a liquid slurry in a state where the raw material powder and the dispersion medium were mixed, and the liquid became liquid. Also became a paste, and the raw material powder did not precipitate. This is because the particle size of Si ₃ N ₄ used in sample 11 and MgO used in sample 21 is small and the specific surface area is large, so that a large amount of dispersion medium is required to wet between the particles of the raw material powder to make it liquid. It is considered that the precipitation was slow because the particle size of Si ₃ N ₄ and MgO was small. The BN used in the sample 14 has a particle size of 7 μm and is not small, but has a plate shape. For this reason, also in the sample 14, like the sample 11 and the sample 21, it is thought that the specific surface area was large, a large amount of dispersion medium was required, and precipitation was also slow. As a result, in Sample 11, Sample 14, and Sample 21, the slurry was in a paste form and the raw material powder was dispersed at a low concentration in the dispersion medium. Therefore, the concentration of the raw material powder in the slurry applied to the surface of the base material is low, the density of the raw material powder in the fired intermediate layer is low, the bond strength due to sintering of the raw material powder is weak, and it can be scraped with a nail It is thought that only hardness was obtained.

Further, from Experimental Example 6, as a hardly sintered material, in addition to SiC, nitrides such as Si ₃ N ₄ , AlN, and BN, carbides such as B ₄ C and WC, and aluminides such as CrAl can be applied. It could be confirmed.
As oxide ceramics, in addition to Yb ₂ SiO ₅ , various silicates such as yttrium silicate, erbium silicate, aluminosilicate, magnesium silicate, single oxides such as Al ₂ O ₃ , SiO ₂ , It was confirmed that glass such as borosilicate glass (Pyrex glass (registered trademark)) can also be applied.
Moreover, as a sol, it was confirmed that an alumina sol can be applied in addition to a silica sol.

FIG. 1 is an enlarged schematic cross-sectional view showing a part of a ceramic matrix composite member of the present invention. FIG. 2 is a cross-sectional view for explaining an example of a ceramic matrix composite material (CMC) constituting the ceramic matrix composite member of the present invention. FIG. 3 is a schematic diagram for explaining volume shrinkage due to sintering of oxide ceramics constituting the intermediate layer. FIG. 4 is a schematic diagram for explaining volume shrinkage due to sintering of the stress relaxation material. FIG. 5 is a flowchart for explaining a method of forming the stress relaxation layer and the intermediate layer in Experimental Example 1. FIG. 6 is a photomicrograph of a cross section of the substrate 1 on which the stress relaxation layer 2 and the intermediate layer 3 are formed. FIG. 7 is a photograph of the ceramic matrix composite member of Experimental Example 2. 8A is a photograph of Sample 1, FIG. 8B is a photograph of Sample 2, and FIG. 8C is a photograph of Sample 3. 9A is a photograph of sample 4, and FIG. 9B is a photograph of sample 5. 10A is a photograph of Sample 6, and FIG. 10B is a photograph of Sample 7. 11A is a photograph of Sample 8, FIG. 11B is a photograph of Sample 9, and FIG. 11C is a photograph of Sample 10. FIG. 12 is a flowchart for explaining a method of forming the stress relaxation layer and the intermediate layer in Experimental Example 5. FIG. 13 is a photograph of the base material on which the stress relaxation layer and intermediate layer of Experimental Example 5 were formed. 14A is a photograph of the sample 11, FIG. 14B is a photograph of the sample 12, and FIG. 14C is a photograph of the sample 13. 15A is a photograph of the sample 14, FIG. 15B is a photograph of the sample 15, and FIG. 15C is a photograph of the sample 16. 16A is a photograph of Sample 17, and FIG. 16B is a photograph of Sample 18. 17A is a photograph of the sample 19, and FIG. 17B is a photograph of the sample 20. 18A is a photograph of sample 18, and FIG. 18B is a photograph of sample 20. FIG. 19A is a photograph of the sample 21, and FIG. 19B is a photograph of the sample 22. FIG. 20 is an enlarged schematic cross-sectional view showing a part of a conventional ceramic matrix composite member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base material, 1a ... Coated surface, 1b ... Pore, 2 ... Stress relaxation layer, 3 ... Intermediate layer, 5 ... Coating layer, 8 ... Crevice, 7, 7a, 17, 17a ... Oxide ceramics, 10 ... Ceramics Matrix composite member, 20 ... Ceramic matrix composite material (CMC), 21 ... Ceramic fiber, 22 ... Ceramic matrix.

Claims (9)

A base material having a coated surface on which a coating layer is formed, and a coating layer formed on the coated surface, the ceramic matrix composite material comprising a ceramic fiber and a ceramic matrix attached to the ceramic fiber. A ceramic-based composite member,
To the object to be coated surface side of the substrate, the thermal expansion coefficient have a stress relieving layer value at which stress relaxation material, which are impregnated between the coating layer and the base material, the stress relaxation material, A ceramic-based composite member comprising an oxide ceramic and a hardly sintered material having a sintering shrinkage smaller than that of the oxide ceramic . The substrate has a plurality of pores, and the pores exposed to at least the coated surface of the pores are filled pores filled with the stress relaxation material,
The stress relaxation layer is formed between the surface to be coated and the stress relaxation material filled in the filled pores present at the deepest position from the coated surface among the filled pores. The ceramic matrix composite member according to claim 1. 3. The ceramic-based composite member according to claim 1, wherein a ratio of the filled pores among the pores existing in the stress relaxation layer increases as the coating layer is approached. The intermediate layer made of the stress relaxation material and integrated with the stress relaxation layer is provided between the stress relaxation layer and the coating layer. Ceramic based composite material. 5. The ceramic matrix composite member according to claim 1, wherein the stress relaxation material has a thermal expansion coefficient in the range of more than 3 to 6 [× 10 ⁻⁶ / K]. . The ceramic-based composite member according to claim 1, wherein the stress relaxation material includes SiC and Yb ₂ SiO ₅ . The ceramic base composite member according to any one of claims 1 to 6, wherein the ceramic fiber and / or the ceramic matrix is made of SiC. The ceramic base composite member according to claim 1, wherein the coating layer is made of HfO ₂ . A base material having a coated surface on which a coating layer is formed, and a coating layer formed on the coated surface, the ceramic matrix composite material comprising a ceramic fiber and a ceramic matrix attached to the ceramic fiber. A method for producing a ceramic matrix composite member, comprising:
A relaxation layer forming step of forming a stress relaxation layer by impregnating a stress relaxation material whose thermal expansion coefficient is a value between the substrate and the coating layer on the coated surface side of the substrate;
Look including a coating step of forming the coating layer on the stress relaxation layer of the substrate,
The relaxation layer forming step includes a step of impregnating the base material in a slurry that becomes the stress relaxation material by sintering, and a step of sintering the slurry attached to the base material,
The slurry comprises a raw material powder containing a base material which becomes oxide ceramics by sintering and a hardly sintered material having a sintering shrinkage smaller than that of the oxide ceramics, and sintering of the oxide ceramic powders during sintering. A method for producing a ceramic matrix composite member comprising a dispersion medium comprising a sol and a solvent that contribute to the promotion of bonding by bonding .

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