JPH11264082A - Heat resistant member and production of heat resistant member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress peeling of a ceramic layer for a long time and to contrive a long life of the heat resistant member by increasing a controlling property of a porosity in a ceramic layer in the heat resistant member having the ceramic layer as heat shielding coating, etc. SOLUTION: The heat resistant member is provided with a metallic base material consisting of an alloy consisting essentially of at least one kind selected among Ni, Co and Fe, and a M-Cr-Al-Y alloy layer (M is Ni, Co and Fe) and a ceramic layer coated on the metallic base material in order. In such a case, at least one kind oxide particles 6 selected among WO3 , B2 O3 , Nb2 O3 , Cr2 O3 and NiO are dispersed at an inside of the ceramic layer 3. The oxide particles 6 are removed by heat treating and high temp. environment at practical usage and pores are formed at these parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-resistant member having a ceramic coating layer and a method for manufacturing the same.

[0002]

2. Description of the Related Art As the operating temperature of equipment increases with the aim of increasing the efficiency of high-temperature equipment such as gas turbines for power generation and engines, materials used for equipment components have become higher-level. Characteristics such as high-temperature strength, high-temperature corrosion resistance and oxidation resistance are required. For this reason, a technique of applying a corrosion-resistant and oxidation-resistant metal coating made of an M-Cr-Al-Y alloy (M: Ni, Co, etc.) to the surface of a high-strength Ni-based or Co-based superalloy has been developed. It has already been widely applied as an indispensable technology in turbine moving and stationary blades.

[0003] In the trend of higher temperatures, the corrosion-resistant and oxidation-resistant metal coating alone is already insufficient in material properties, so that a ceramic coating having low thermal conductivity is coated on the surface of the metal coating layer. Thermal barrier coating technology for applying and cooling the inside is also being put to practical use. The types of ceramic materials, high temperature strength, thermal conductivity, the properties such as thermal expansion coefficient, Y ₂ O ₃ stabilized ZrO ₂ is the most widely applied.

[0004] However, when a member in which a thermal barrier coating is applied to the surface of a metal member is used in a high temperature atmosphere, thermal stress is generated due to a difference in thermal expansion coefficient between the metal member and the thermal barrier coating layer (ceramic layer). There is a problem that the ceramic coating layer is easily peeled off. If the ceramic layer is peeled, the heat-resistant member cannot be used continuously for a long time in a high-temperature atmosphere. Therefore, a ceramic layer that is resistant to peeling is desired from the viewpoint of extending the life of the thermal barrier coating member.

[0005] Therefore, in order to suppress the separation of the ceramic layer, a structure is adopted in which the porosity in the ceramic layer is increased to reduce the thermal stress. Although an increase in porosity is effective in relieving thermal stress, it causes a decrease in strength of the ceramic layer. For this reason, it is desired to produce a coating layer that suppresses a decrease in the strength of the ceramic layer as much as possible and has a high thermal stress relaxation property.

For example, when a ceramic layer is formed by a thermal spraying method, attempts have been made to adjust the porosity in the ceramic layer by controlling the particle size of the thermal spray raw material powder and the thermal spraying conditions. However, in reality, it is very difficult to precisely control the porosity by controlling the thermal spraying conditions. For this reason, a ceramic layer having an optimal porosity cannot be produced with good reproducibility, and there is a problem that the ceramic layer is peeled off when a heat-resistant member is used for a long time.

Further, when forming a ceramic layer comprising a stabilized ZrO ₂ layer or the like by a thermal spraying method, a low melting point NaCl is mixed with the thermal spraying raw material powder, and the NaCl is melted after the ceramic layer is formed by the thermal spraying method. Thus, formation of pores in a ceramic layer has been studied. However, this method has a problem that ZrO ₂ and NaCl react with each other to cause deterioration of characteristics of the ceramic layer, and that Na remaining in the ceramic layer adversely affects the metal base material. Since the controllability of the pores is also insufficient, it cannot be said that this is a realistic method of forming pores.

[0008]

As described above, in a conventional heat-resistant member having a ceramic layer, attempts have been made to increase the porosity in the ceramic layer in order to suppress the separation of the ceramic layer due to thermal stress. However, it is very difficult to precisely control the porosity by simply adjusting the thermal spraying conditions, for example. In addition, it has been considered to mix NaCl or the like into the thermal spraying raw material. However, such a method has a problem that the ceramic layer and the metal base material are adversely affected.

As described above, in the conventional heat-resistant member and the method of manufacturing the same, a ceramic layer having an optimum porosity cannot be obtained with good reproducibility. There was a problem. Therefore, it is strongly desired to improve the controllability of the porosity in the ceramic layer and to improve the releasability of the ceramic layer as a thermal barrier coating with good reproducibility.

The present invention has been made to address such a problem, and it has been made possible to suppress the peeling of the ceramic layer for a long time by improving the controllability of the porosity in the ceramic layer. It is an object of the present invention to provide a heat-resistant member having a longer life and a method of manufacturing the heat-resistant member.

[0011]

According to a first aspect of the present invention, there is provided a heat-resistant member comprising a metal substrate made of an alloy containing at least one element selected from Ni, Co and Fe as a main component. , MC coated on the metal substrate
r-Al-Y alloy layer (where M is Ni, Co and F
e), and a ceramic layer provided on the M-Cr-Al-Y alloy layer, wherein a tungsten oxide, an oxide, Boron, niobium oxide,
At least one selected from chromium oxide and nickel oxide
It is characterized in that one kind of oxide particles is dispersed.

Further, according to a second aspect of the present invention, there is provided a method for manufacturing a heat-resistant member, comprising: a metal base comprising an alloy mainly containing at least one element selected from Ni, Co and Fe; MC coated on the metal substrate
r-Al-Y alloy layer (where M is Ni, Co and F
e) and a ceramic layer coated on the M-Cr-Al-Y alloy layer to produce a heat-resistant member comprising the ceramic layer. The above-described M-Cr-Al is obtained by using a raw material containing a matrix material and at least one oxide selected from tungsten oxide, boron oxide, niobium oxide, chromium oxide and nickel oxide.
A step of forming the ceramic layer on the -Y alloy layer, and a step of performing a heat treatment on the ceramic layer at a temperature at which the oxide sublimates to form pores inside the ceramic layer. I have.

In the heat-resistant member of the present invention, oxides having high sublimability at high temperatures, ie, W, B, Nb, Cr and N
An oxide containing at least one element selected from i is dispersed in the ceramic layer. Such a ceramic layer is subjected to a heat treatment step shown in the method for manufacturing a heat-resistant member of the present invention, or is exposed to a high-temperature environment during actual use, thereby removing oxides having a high sublimation property and removing the ceramic layer. Pores can be formed inside. Such pores can be controlled by the shape, size, amount, etc. of the oxide particles dispersed in the ceramic layer. Therefore, a desired shape and a desired amount of pores can be dispersed with good reproducibility at an arbitrary position inside the ceramic layer. Further, since the oxide forming the pores is removed by sublimation, there is no adverse effect on the ceramic layer and the metal substrate.

[0014]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view showing a schematic structure of one embodiment of the heat-resistant member of the present invention. In FIG. 1, reference numeral 1 denotes a metal substrate, and the metal substrate 1 includes an alloy mainly containing at least one selected from Ni, Co and Fe. An alloy can be appropriately selected and used. Practically, IN7
38, IN738LC, IN939, Mar-M24
7, RENE80, CM-247, CMSX-2, CM
Ni-based superalloys such as SX-4, FSX-414, Ma
It is effective to use a Co-based superalloy such as r-M509.

On the above-mentioned metal substrate 1, an M-Cr-Al-Y alloy layer (M is Ni,
2 (indicating at least one element selected from Co and Fe). This M-Cr-Al-Y
In order to obtain a function as a corrosion-resistant and oxidation-resistant metal coating, the alloy layer 2 is generally 0.1 to 20% by weight of Al, 10 to 10% by weight.
35% by weight of Cr, 0.1 to 5% by weight of Y, the balance being N
An alloy having a composition substantially composed of at least one M element selected from i, Co and Fe is used. Note that A
It is sufficient that l and Cr contain at least one of them, and other active metals such as Hf, Zr, and Ti can be used instead of Y. In some applications, Nb, T
a, W, etc. may be contained in the range of about 5% by weight or less. Here, the above alloys are collectively referred to as MC
It is called r-Al-Y alloy. Specifically, NiCoCrAl
Y alloy, CoNiCrAlY alloy, NiCrAlY alloy, CoCrAlY alloy, FeCrAlY alloy and the like are preferably used.

The M—Cr—Al—Y alloy layer 2 is formed by a thermal spraying method.
Although it can be formed by various film forming methods such as a PVD method and a CVD method, a thermal spraying method is most effective in practical use.
In particular, a reduced pressure spraying method (low vacuum spraying method) or a high-speed gas flame spraying method (HOVF) that can obtain a denser coating layer than the atmospheric spraying method.
It is preferable to apply the M-Cr-Al-Y alloy layer 2 by the entrained oxygen during the formation of the coating layer.
Internal oxidation can be suppressed. In addition, M-Cr-
The thickness of the Al—Y alloy layer 2 can be selected from the range of about 10 to 500 μm according to the application.
About 300 μm is appropriate.

A ceramic layer 3 is formed on the M-Cr-Al-Y alloy layer 2 as a thermal barrier coating, for example, so that a heat-resistant member 4 used as a constituent material of high-temperature equipment is formed. It is configured.
The thickness of the ceramic layer 3 is preferably about 50 to 500 μm, although it depends on the intended use of the heat-resistant member 4. The ceramic layer 3 is formed by plasma spraying, H
Although it can be formed by various film forming methods such as a thermal spraying method such as a VOF method, a PVD method, a CVD method, and a spin coating method, a plasma spraying method is most effective for practical use.

The constituent material of the ceramic layer 3 is a group 4A metal such as zirconium oxide, hafnium oxide, or titanium oxide having a large coefficient of thermal expansion in order to reduce thermal stress caused by a difference in coefficient of thermal expansion from the metal substrate 1. It is preferable to use a rare earth oxide such as an oxide of cerium or cerium oxide (CeO ₂ ). In particular, an oxide containing a group 4A metal oxide represented by ZrO ₂ as a main component and a rare earth oxide such as yttrium oxide or cerium oxide or an alkaline earth oxide added thereto is preferably used.

In zirconium oxide (ZrO ₂ ), a stabilizer such as a rare earth oxide or an alkaline earth oxide is added in order to suppress a phase transition caused by a thermal history. It is preferable to use the configured partially stabilized zirconia or stabilized zirconia. On the other hand, if about 1 to 30% of monoclinic zirconia is distributed inside the ceramic layer 3, fine cracks can be formed in the layer, which is preferable from the viewpoint of thermal stress relaxation. it can. Further, it is preferable that the monoclinic zirconia have a stabilizer in solid solution from the viewpoint of chemical stability.

The above ceramic layer 3 is shown in FIG.
As shown in FIG. 5, tungsten oxide (WO ₃ ), boron oxide (B ₂ O ₃ ), and niobium oxide (Nb ₂ O ₃ ) are dispersed and arranged in the matrix particles 5 constituting the ceramic layer 3 and between the particles. And at least one oxide particle 6 selected from chromium oxide (Cr ₂ O ₃ ) and nickel oxide (NiO). Here, FIG. 2 shows the ceramic layer 3 formed by the thermal spraying method, and the matrix particles 5 are thermal spray solidified particles (melt solidified particles).

WO ₃ and B are used as oxide particles having high sublimability at high temperature within or between the particles of the spray-solidified particles 5.
_At least one kind of oxide particles 6 selected from ₂ O ₃ , Nb ₂ O ₃ , Cr ₂ O ₃ and NiO is dispersed. FIG. 2 shows a state before actual use or a state before heat treatment to be described later. By subjecting such a ceramic layer 3 to heat treatment before actual use, or by exposing the ceramic layer 3 to a high-temperature environment during actual use, oxide particles 6 having a high sublimation property are removed, and as shown in FIG. Thus, pores 7 are formed at positions where oxide particles 6 existed. Here, FIG. 3 shows a state in which a heat treatment is performed on the ceramic layer 3 before actual use, or a state after the heat-resistant member 4 is actually used.

As described above, the oxide particles 6 having high sublimability are dispersed and arranged in the ceramics layer 3 and the oxide particles 6 are removed by heat treatment before actual use or by a high-temperature environment exposed during actual use. Pores 7 are obtained based on the shape, dispersion position, dispersion amount and the like of the oxide particles 6. As described above, in the present invention, the oxide particles 6 that sublime at a high temperature are used as means for controlling the shape, amount, and distribution of the pores 7 existing in the ceramic layer 3. Therefore, by controlling the shape, the dispersing position, the dispersing amount, etc. of the oxide particles 6 arranged in the ceramic layer 3, the pores 7 having a desired amount and a desired shape can be dispersed at a desired position, and the optimal pores can be dispersed. It is possible to obtain the ceramic layer 3 having a good reproducibility. That is, peeling of the ceramic layer 3 due to thermal stress can be suppressed stably. further,
Since the oxide particles 6 that form the pores 7 are sublimated and removed, the oxide particles 6 do not adversely affect the ceramic layer 3 and the metal substrate 1.

The formation position of the pores 7 depends on the dispersion position of the oxide particles 6 having high sublimability. Such oxide particles 6
The dispersion position of the matrix particles (spray solidified particles, etc.)
For example, in the case of the ceramic layer 3 formed by a thermal spraying method, in order to obtain a better thermal stress relaxation effect, the thermal spray solidified particles 5 It is preferred to be present between particles of flat particles called lamellar structures that can be seen. In other words, by having the pores 7 between the particles of the spray-solidified particles 5,
A better thermal stress relaxation effect is obtained.

The dispersion position of the oxide particles 6 can be controlled according to the form of the thermal spray raw material when the ceramics layer 3 is formed by thermal spraying, for example. For example, by using a mixed powder of a matrix powder constituting the ceramic layer 3 and an oxide powder having a high sublimability as a spraying raw material powder, the oxide particles 6 and the pores 7 are present between the particles of the spray-solidified particles 5. Can be done. Also,
By using a powder in which a highly sublimable oxide was previously present inside the matrix particles as a spraying raw material powder,
The oxide particles 6 and further the pores 7 can be formed in the particles of the thermal spray solidified particles 5.

The size of the pores 7 depends on the particle diameter of the oxide particles 6 having high sublimability. The particle diameter of such oxide particles 6 is preferably in the range of 0.1 to 200 μm. If the particle size of the oxide particles 6 is less than 0.1 μm, the oxide particles 6
May not be satisfactorily dispersed. On the other hand, if the particle diameter of the oxide particles 6 exceeds 200 μm, the size of the pores 7 formed after the heat treatment or after actual use becomes too large, causing a decrease in the mechanical strength of the ceramic layer 3 or the pores 7 themselves. May be a starting point of a peeling crack. More preferably, the particle diameter of the oxide particles 6 is in the range of 0.1 to 150 μm.

Further, the amount of the pores 7 substantially depends on the amount of dispersion of the oxide particles 6 having high sublimability, and can be arbitrarily controlled according to the amount of dispersion of the oxide particles 6. Can also be arbitrarily controlled according to the initial distribution of the oxide particles 6. The dispersion amount of such oxide particles 6 is preferably in the range of 10 to 50% in volume ratio as a whole of the ceramic layer 3, and the dispersion amount when the heat-resistant member 4 is used for a gas turbine or the like is 10 to 50%. It is desirable to set the range to 30%.

When the amount of the oxide particles 6 is less than 10% by volume with respect to the ceramic layer 3, the amount of the pores 7 becomes insufficient, and the ceramic layer 3 is sufficiently provided with a thermal stress relaxation effect. May not be possible. On the other hand, if the amount of the oxide particles 6 exceeds 50% by volume with respect to the ceramic layer 3, the strength of the ceramic layer 3 may be reduced. According to the ceramic layer 3 having such an amount of the oxide particles 6, the pores 7 having a volume ratio in the range of 10 to 50% (more preferably 10 to 30%) are formed due to the heat treatment or the high temperature environment during actual use. can get.

Here, an appropriate distribution of the pores 7 in the ceramic layer 3 differs depending on, for example, which one of the principal is the peeling resistance and the erosion resistance. For example, in order to suppress the peeling of the ceramic layer 3, (A) a structure in which the porosity of the entire ceramic layer 3 is sufficiently increased to enhance thermal stress relaxation, and (B) a metal member where the thermal stress is concentrated. It is preferable to strengthen the portion near the interface with, and make the remaining portion a structure having high thermal stress relaxation. That is, in the former (A), pores are uniformly distributed in the ceramic layer 3 in an appropriate amount, and in the latter (B), pores inside the ceramic layer 3 increase from the interface with the metal member toward the surface. Ceramic layer 3 with excellent peeling resistance
Is obtained.

For example, when the ceramic layer 3 is formed under a single thermal spraying condition as in the structure (A), the ceramic layer 3 has a Vickers hardness of 650 Hv (load
(200 gf, 30 seconds) or less. In such a case, the ceramic layer 3 having particularly excellent thermal stress relaxation properties can be obtained.

In order to reinforce the portion of the ceramic layer 3 where the stress is concentrated, as in the structure (B) described above,
The porosity of the ceramic layer 3 near the metal member is reduced,
To increase the porosity near the surface, use M-Cr-
The range of about 200 μm from the interface with the Al—Y alloy layer 2 is
The Vickers hardness is preferably 650 Hv (load: 200 gf, 30 seconds) or more, which can suppress the occurrence of cracks. When the thickness of the ceramic layer 3 is 200 μm or more, the remaining portion has a Vickers hardness of 650 Hv (load
(200 gf, 30 seconds) or less, and a layer having high porosity and excellent thermal stress relaxation. According to such a multilayer structure, generation of a crack and propagation of the crack can be suppressed, and the peeling resistance of the ceramic layer 3 can be improved.

On the other hand, for the purpose of improving the erosion resistance, a structure having a small porosity can be formed in a range of about 50 μm from the surface of the ceramic layer 3.

Next, a method for forming the above-mentioned ceramic layer 3 will be described. Here, the case where the ceramics layer 3 is formed by the thermal spraying method will be mainly described, but the ceramics layer 3 may be formed by the EB-PVD method or the C
It can also be formed by another film formation method such as a VD method, and in this case, various conditions are set according to the selected film formation method.

First, the matrix material of the ceramic layer 3 and WO ₃ , B ₂ O
₃ , a thermal spray raw material powder containing at least one oxide selected from Nb ₂ O ₃ , Cr ₂ O ₃ and NiO is prepared. At this time, the matrix material of the ceramic layer 3 and the oxide having high sublimability at high temperature include (1) mixing these powders, and (2) the oxide having high sublimability at high temperature is mixed with the ceramic constituting the matrix. It can be mixed by dispersing inside the particles.

As described above, according to the powder (1), the oxide particles 6 and the pores 7 can be present between the particles of the spray-solidified particles 5. According to the powder (2), the thermal spray The oxide particles 6 and further the pores 7 can be present in the solidified particles 5.

Next, the ceramic layer 3 is formed on the M-Cr-Al-Y alloy layer 2 formed on the metal substrate 1 by using, for example, the plasma spraying method by using the above-mentioned spraying raw material powder. . In addition, it is also possible to form the ceramic layer 3 by spraying each raw material powder (each raw material powder of matrix particles and oxide particles) from each of the plurality of thermal spray guns.

The ceramic layer 3 thus formed
Has oxide particles 6 dispersed and arranged between the particles of the spray-solidified particles 5 and in the particles, as shown in FIG. As described above, the shape, size, dispersion position, dispersion amount, and the like of the oxide particles 6 are appropriately set according to the target pores 7.

When the pores 7 are previously formed in the ceramic layer 3, the above-mentioned ceramic layer 3 is subjected to the following heat treatment. Further, the heat-resistant member 4 of the present invention can be used for practical use in a state where the oxide particles 6 are dispersed and arranged inside the ceramic layer 3. In this case, the oxide particles 6 are sublimated by the high-temperature environment during actual use of the heat-resistant member 4, and desired pores 7 are formed.

The heat treatment applied to the ceramic layer 3 in advance is performed at a temperature at which the oxide particles 6 sublime, for example, 500 to 1400 ° C.
It is carried out at a temperature in the range of The heat treatment may be performed in the atmosphere, but may be performed in an inert atmosphere or a vacuum atmosphere in consideration of the deterioration of the metal substrate 1 and the like. At such a heat treatment temperature, there is no adverse effect on the metal substrate 1 made of a Ni-based superalloy, a Co-based superalloy, or the like. The heat treatment temperature is preferably set according to the type of the oxide particles 6.

The heat treatment as described above is applied to the ceramic layer 3.
In this case, the oxide particles 6 dispersed in the ceramic layer 3 are removed by sublimation, and the pores formed at the positions where the oxide particles 6 were present as shown in FIG. 7 is obtained. The pores 7 thus obtained can be controlled by the shape, size, dispersion position, dispersion amount, and the like of the oxide particles 6.
A desired amount of pores 7 can be formed at a desired position in a desired size with a good reproducibility. Therefore, the ceramic layer 3 having excellent thermal stress relaxation can be obtained with good reproducibility, and the life of the heat-resistant member 4 can be extended.

[0041]

EXAMPLES Next, specific examples of the present invention and evaluation results thereof will be described.

Example 1 On the surface of a round bar made of a Ni-base super heat-resistant alloy CM-247,
NiCoCrA about 150μm thick by plasma spraying
After forming the 1Y layer, an additional 8% by weight of Y ₂ O ₃ stabilized Z
20 weight per rO ₂ powder (melt pulverized powder, particle size: 10-44 μm)
% Of WO ₃ powder (particle size: 1 to 80 μm) was mixed as a raw material powder for thermal spraying to form a ceramic layer having a thickness of 250 μm. When an SEM observation and a backscattered electron image observation of the obtained ceramics layer were performed, it was confirmed that WO ₃ particles were dispersed inside the ceramics layer.

Next, the sample on which the ceramic layer was formed was heat-treated at 800 ° C. for 2 hours and subsequently at 1000 ° C. for 16 hours. When the structure of the ceramic layer after the heat treatment was observed by SEM, no WO ₃ particles were found inside the ceramic layer, and it was confirmed that pores were formed between the spray-solidified particles. The pore volume ratio was about 25%. The sample thus obtained was subjected to the characteristic evaluation described later.

Example 2 The surface of a round bar made of a Ni-base superalloy CMSX-2 was
NiCoCrA about 140μm thick by plasma spraying
After forming the 1Y layer, an additional 8% by weight of Y ₂ O ₃ stabilized Z
30 weight to rO ₂ powder (melt pulverized powder, particle size: 10-44 μm)
% Of NiO powder (particle size: 1 to 40 μm) was mixed and used as a thermal spraying raw material powder to form a ceramic layer having a thickness of 250 μm. SEM observation of the obtained ceramics layer confirmed that NiO particles were dispersed inside the ceramics layer.

Next, the sample on which the ceramic layer was formed was heat-treated at 800 ° C. for 3 hours and subsequently at 1000 ° C. for 16 hours. When the structure of the ceramic layer after the heat treatment was observed with a SEM, no NiO particles were observed inside the ceramic layer, and it was confirmed that pores were formed between the spray-solidified particles. The pore volume ratio was about 20%. The sample thus obtained was subjected to the characteristic evaluation described later.

Example 3 A round bar made of a Ni-base superalloy CMSX-2 was
NiCoCrA about 140μm thick by plasma spraying
After forming the 1Y layer, first, 8 wt% Y ₂ O ₃ stabilized Zr
O ₂ powder (fused and crushed powder, particle size: 10~44μm) the use as a thermal spraying material powder was formed by coating a ceramic layer with a thickness of 150 [mu] m. Further, the same composition of Y ₂ O ₃ stabilized ZrO
_{2 A} powder obtained by mixing 20% by weight of WO ₃ powder (particle size: 1 to 100 μm) with
A coating was formed with a thickness of 100 μm. SEM observation of the obtained ceramics layer confirmed that WO ₃ particles were dispersed on the surface side of the ceramics layer.

Next, the sample on which the ceramic layer having the two-layer structure was formed was heat-treated at 800 ° C. for 3 hours and subsequently at 1000 ° C. for 16 hours. The ceramic layer after heat treatment
When the structure was observed by EM, W was found inside the ceramic layer.
No O ₃ particles were observed, confirming that pores were formed between the spray-solidified particles. The total volume ratio of pores is about 20
%Met. The sample thus obtained was subjected to the characteristic evaluation described later.

Example 4 The surface of a round bar made of a Ni-base superalloy CM-247 was
NiCoCrA about 150μm thick by plasma spraying
After forming the 1Y layer, an additional 8% by weight of Y ₂ O ₃ stabilized Z
0% by weight, 5% by weight, 10% by weight, 15% by weight, and 20% by weight of WO to rO ₂ powder (melt ground powder, particle size: 10 to 44 μm)
_{Using a} mixed powder of the _three powders (particle size: 1 to 50 μm) as a thermal spraying raw material powder, a ceramic layer was formed so as to increase the amount of WO ₃ from directly above the NiCoCrAlY layer toward the surface. The total thickness of the ceramic layer is 250
μm. SEM observation of the obtained ceramic layer confirmed that WO ₃ particles were dispersed inside the ceramic layer so as to increase toward the surface.

Next, the sample on which the ceramic layer was formed was heat-treated at 800 ° C. for 2 hours and subsequently at 1000 ° C. for 16 hours. When the structure of the ceramic layer after the heat treatment was observed by SEM, no WO ₃ particles were found inside the ceramic layer, and it was confirmed that pores were formed between the spray-solidified particles. The volume ratio of pores (average value of the entire ceramic layer) was about 25%. The sample thus obtained was subjected to the characteristic evaluation described later.

Comparative Example 1 On the surface of a round bar made of a Ni-base super heat-resistant alloy CMSX-2,
NiCoCrA about 140μm thick by plasma spraying
After forming the Y layer, 8% by weight Y ₂ O ₃ stabilized ZrO ₂
Using a powder (melt pulverized powder, particle size: 10 to 44 μm) as a thermal spraying raw material powder, a ceramic layer having a thickness of 250 μm was formed by coating.

Next, the sample on which the ceramic layer was formed was heat-treated at 800 ° C. for 2 hours and subsequently at 1000 ° C. for 16 hours. When the structure of the ceramic layer after the heat treatment was observed with a SEM, few pores were observed between the spray-solidified particles. The sample thus obtained was subjected to the characteristic evaluation described later.

The samples of Examples 1 to 4 and the sample of Comparative Example 1 were each subjected to 250 M
A stress test of Pa was applied, and a repeated heating test with room temperature was performed in a 12-hour cycle. As a result, in each of the samples of Examples 1 to 4, peeling of the ceramics layer did not occur even when the number of cycles exceeded 1,000. After observing the cross section of the sample after the test,
Almost no cracks were found inside the Y-stabilized ZrO ₂ layer. On the other hand, in the sample of Comparative Example 1, peeling of the zirconia layer started in 50 cycles, and completely peeled in 100 cycles.

Example 5 The surface of a round bar made of a Ni-base super heat-resistant alloy CM-247 was
NiCoCrA about 150μm thick by plasma spraying
After forming the 1Y layer, an additional 8% by weight of Y ₂ O ₃ stabilized Z
20 weight per rO ₂ powder (melt pulverized powder, particle size: 10-44 μm)
% Of WO ₃ powder (particle size: 1 to 100 μm) was used as a material for thermal spraying to form a ceramic layer having a thickness of 250 μm. SEM of the obtained ceramic layer
As a result of observation, WO ₃ was found inside the ceramic layer.
It was confirmed that the particles were dispersed.

The sample thus obtained was left for 50 hours in an atmosphere of 900 ° C. simulating the environment during operation of a gas turbine. Then, apply a stress of 250MPa in the atmosphere of 850 ℃,
A repeated heating test with room temperature was performed in a 12-hour cycle. As a result, in the sample of Example 5, peeling of the ceramics layer did not occur even after more than 200 cycles. When the cross section of the sample was observed after the test, it was confirmed that pores were present between the zirconia particles constituting the ceramic layer.

[0055]

As described above, according to the present invention,
Pores can be obtained in the ceramic layer with a desired amount, a desired shape, a desired size, and a desired distribution with good reproducibility.
Therefore, the peeling of the ceramic layer can be suppressed for a long time, and the reliability and life of the heat-resistant member can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main structure of an embodiment of a heat-resistant member of the present invention.

FIG. 2 is an enlarged schematic view showing a structure of a ceramic layer of the heat-resistant member shown in FIG.

FIG. 3 is a schematic view showing a state after heat treatment of the ceramic layer shown in FIG. 2 or after exposure to a high-temperature environment during actual use.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal base material 2 ... M-Cr-Al-Y alloy layer 3 ... Ceramics layer 4 ... Heat resistant member 5 ... Matrix particles 6 ... Oxide particles 7 ... Pores

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroki Inagaki 1 Tokoba Toshiba-cho, Komukai-ku, Kawasaki-shi, Kanagawa Inside the R & D center of Toshiba Corporation

Claims (2)

[Claims] 1. A metal base made of an alloy containing at least one element selected from Ni, Co and Fe as a main component, and an M-Cr-Al- coating formed on the metal base.
A Y alloy layer (where M represents at least one element selected from Ni, Co and Fe) and the M-Cr-
A heat-resistant member comprising a ceramic layer provided on an Al-Y alloy layer, wherein at least one oxide selected from tungsten oxide, boron oxide, niobium oxide, chromium oxide, and nickel oxide is provided inside the ceramic layer. A heat-resistant member having particles dispersed therein. 2. A metal base made of an alloy containing at least one element selected from Ni, Co and Fe as a main component, and an M-Cr-Al-coated on the metal base.
A Y alloy layer (where M represents at least one element selected from Ni, Co and Fe) and the M-Cr-
In manufacturing a heat-resistant member including a ceramic layer coated on an Al-Y alloy layer, a matrix material mainly constituting the ceramic layer, and tungsten oxide, boron oxide, niobium oxide, chromium oxide, and nickel oxide Using a material containing at least one selected oxide, the M-Cr-A
a step of coating the ceramic layer on the l-Y alloy layer, and a step of subjecting the ceramic layer to a heat treatment at a temperature at which the oxide sublimates to form pores in the ceramic layer. A method for manufacturing a heat-resistant member.