JPH0949089A - Heat resistant member and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a heat resistant member preventing the deterioration of the coating layer due to the formation of a nitride and the deterioration of the substrate by improving nitriding resistance. SOLUTION: In this heat resistant member provided with a metallic coating layer made of an M-Cr-Al-Y alloy layer (M is Fe, Ni or Co) 2a coated on the surface of a substrate 1, the M-Cr-Al-Y alloy layer 2a includes a region 2b in which at least one kind of nitride forming element selected from among Sc, Th, Ce, La, Ti, Zr, Hf, Nb and Ta is contained at a high concn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant member suitable for members that require durability and reliability under high temperature and high stress, such as constituent members such as moving and stationary blades of a gas turbine. And a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, energy devices typified by gas turbines have been energetically promoted to be highly efficient. The most effective means for achieving such high efficiency is to raise the operating temperature of the equipment, but along with this, the material characteristics required for equipment constituent members are becoming more severe. Since high-temperature equipment is exposed to a high-temperature oxidative / corrosive environment, high-temperature strength, corrosion resistance, oxidation resistance, etc. are important as material properties required for constituent members of high-temperature equipment.

However, it is difficult for a conventional heat-resistant alloy such as iron-based alloy, nickel-based alloy or cobalt-based alloy to satisfy both the high temperature strength and the corrosion / oxidation resistance at the same time. Corrosion- and oxidation-resistant coating technology for heat-resistant alloys has been developed and has a considerable track record in actual machines.

As such a corrosion / oxidation-resistant coating material, an M-Cr-Al-Y alloy (M is Fe, Ni and C) is used.
At least one element selected from o) is generally used. This M-Cr-Al-Y alloy contains M element as a main component which is excellent in high temperature strength and compatibility with a base material, and Al and Cr which form an oxide coating having a high corrosion / oxidation resistance effect.
It is composed of Y which enhances the adhesion of the coating layer and the oxide film.

P by the above-mentioned M-Cr-Al-Y alloy
Various methods such as the VD method and the CVD method have been studied. Of these, the plasma spraying method can be used to form a thick film easily, and is therefore used as the most effective coating method for the M-Cr-Al-Y alloy layer.

[0006] By the way, the existing M-Cr-Al-Y alloys have been developed in terms of corrosion resistance and oxidation resistance, so that little consideration was given to nitriding resistance.

However, the surface of the heat-resistant alloy is
When the heat-resistant member coated with the -Al-Y alloy layer is operated under high-temperature conditions for a long time, the heat-resistant member is exposed from the inside of the M-Cr-Al-Y alloy layer toward the inside of the heat-resistant alloy of the base material in a combustion gas atmosphere. It has been found that nitrogen of Al produces a nitride such as Al and Ti, and the substrate itself is damaged due to the influence of the nitride itself, the peeling of the coating layer on the surface, and the like, resulting in a significant decrease in life.

In particular, when the coating layer having high oxidation resistance is formed, the potential of oxygen inside the material is reduced, so that the potential of nitrogen is relatively increased and the nitriding may be promoted. Was issued.

Further, a ceramic coating layer having a low thermal conductivity such as a Y-stabilized ZrO ₂ layer is further provided on the metal coating layer made of an M-Cr-Al-Y alloy or the like to provide a heat shielding effect. However, even in the heat resistant member having such a structure, the base material is damaged due to the formation of nitride in the base material.

As mentioned above, the conventional M-Cr-Al-
A metal coating material using a coating layer made of a Y alloy is MC
Since the r-Al-Y alloy itself has been developed with an emphasis on oxidation resistance, it does not have sufficient nitriding resistance, and if it is operated under high temperature conditions for a long time, the M-Cr-Al-Y alloy There is a problem that nitrides are formed inside the layers and inside the base material, and the coating layer and the base material are damaged. Therefore, there is a demand for a heat-resistant member that has improved corrosion resistance and oxidation resistance as well as nitriding resistance.

In addition to the gas turbine, the nitriding problem has become apparent not only in the chemical vessel structural parts such as the reaction vessel and piping of the ammonia generation plant, the boiler tube of the waste treatment plant, or the nuclear power plant structural parts. Therefore, there is a high demand for heat resistant members having high nitriding resistance.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to address such problems, and it is intended to improve nitriding resistance while satisfying heat resistance and corrosion / oxidation resistance. Accordingly, it is an object of the present invention to provide a heat-resistant member that prevents deterioration such as peeling of a metal coating layer due to the formation of nitrides and deterioration of a base material, and a manufacturing method for obtaining the heat-resistant member with good reproducibility.

[0013]

A first heat-resistant member according to the present invention comprises a base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component, and coating the surface of the base material. M-Cr-Al-Y alloy layer (where M represents at least one element selected from Fe, Ni and Co), and the M-Cr-Al-Y alloy layer Sc, Th, Ce, L
It is characterized in that at least one nitride forming element selected from a, Ti, Zr, Hf, Nb and Ta contains a region having a higher concentration than the MCrAl alloy.

The second heat resistant member in the present invention is Fe,
A base material made of an alloy whose main component is at least one element selected from Ni and Co, and an M-Cr-Al-Y alloy layer coated on the surface of the base material (where M is Fe and N).
i and at least one element selected from Co), and the above-mentioned M-Cr-A
Sc, Th, Ce, L is added to the vicinity of the surface of the l-Y alloy layer.
At least one nitride-forming element selected from a, Ti, Zr, Hf, Nb and Ta is added to the above M-Cr-Al-
It is characterized in that a layer containing a higher concentration than the Y alloy is provided.

The third heat-resistant member is a base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component, and M- coated on the surface of the base material.
A Cr-Al-Y alloy layer (where M represents at least one element selected from Fe, Ni and Co), the M-Cr-Al-Y alloy layer is Sc, Th, Ce, La, Ti, Zr, Hf, N
From a matrix phase containing at least one nitride forming element selected from b and Ta and containing the M element as a main component, and an intermetallic compound phase containing the M element, Al element and the nitride forming element. It is characterized by being mainly configured.

The fourth heat-resistant member according to the present invention comprises Fe, N
A base material made of an alloy containing at least one element selected from i and Co as a main component, and an M-Cr-Al-Y alloy coated on the surface of the base material (where M is Ni, C
a metal coating layer comprising at least one element selected from o and Fe), the metal coating layer has an oxide layer on the surface side, and The feature is that the initial precipitates are present in an area ratio of 10% or more in the range of 5 μm in the thickness direction.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The base materials in the first, second, third and fourth heat resistant members of the present invention are Fe, Ni and Co.
Any heat-resisting alloy may be used as long as it is made of an alloy containing at least one element selected from the following as a main component, and a known heat-resistant alloy can be appropriately selected and used depending on the application. Practically, IN738, IN939, Mar-M247, Re
Ni-based superalloy such as ne80, FSX-414, Mar
It is effective to use a Co-based superalloy such as -M509. The composition of the above alloys is shown in Table 1.

[0018]

[Table 1]

The M-Cr-Al-Y alloy layer (where M is at least one selected from Fe, Ni and Co) in the first, second, third, and fourth heat-resistant members of the present invention is 0.1. ~
20 wt% Al, 10-40 wt% Cr, 0.1-
It is preferable to use an alloy having a composition containing 1.5% by weight of Y and the balance being substantially M.

Al and Cr are elements responsible for corrosion resistance and oxidation resistance. If the contents of Al and Cr are less than the lower limit of the above range, the corrosion resistance and oxidation resistance of the coating layer may be deteriorated and the sufficient function may not be exhibited. On the other hand, if it exceeds the upper limit of the above range, the production of harmful intermetallic compound layers is promoted, and the ductility of the metal coating layer is reduced, so that the life may be shortened due to crack growth in the metal coating layer. . A more preferable composition ratio of Al and Cr is 3 for Al.
˜15 wt% and Cr in the range of 15-35 wt%.

Y is an element that improves the adhesiveness of the oxide layer and the metal coating layer, and the effect is reduced in any case outside the above range. A more preferable composition ratio of Y is in the range of 0.3 to 1% by weight.

The balance of the M element may be at least one element selected from Fe, Ni and Co. From the viewpoint of compatibility with the base alloy and life, in particular, a single element of Ni or Co, or Ni and Co (Ni> Co) or Co and N
A combination of i (Co> Ni) is preferred.

Further, a small amount of Ti, Hf, Ta, Zr or Nb may be added to this alloy for the purpose of improving oxidation resistance. First, the first heat resistant member will be described in detail. The first heat-resistant member is M-Cr-Al formed by coating on the surface of the base material.
-Sc, Th, Ce, La, Ti, Zr, Hf, Nb in a metal coating layer made of a Y alloy (where M represents at least one element selected from Ni, Co and Fe).
And at least one nitride-forming element selected from Ta includes a region having a higher concentration than the surrounding M-Cr-Al-Y alloy base material. It is necessary that the standard free energy of formation of nitrides is lower than or equal to that of Al at temperatures of 973 K or higher, which is the operating temperature of the turbine. These nitride-forming elements are M-Cr-A
By including a region having a higher concentration than that of the l-Y alloy base material, it is possible to suppress the penetration of nitrogen into the material and significantly suppress the generation of Al nitrides and the like. The nitridation of Al hinders the formation of a protective oxide film and causes a significant deterioration of the coating layer. Therefore, at least one kind of nitride forming element selected from Sc, Th, Ce, La, Ti, Zr, Hf, Nb and Ta is added to the M-Cr-Al-Y alloy layer to penetrate into the coating layer. The nitriding of Al can be suppressed by trapping the generated nitrogen with a nitride-forming element, which makes it possible to extend the life of the metal coating material in the presence of nitrogen.

Further, the region containing a high concentration of the nitride-forming element contains Cr, Al and Y in the same extent as in the above-mentioned main M-Cr-Al-Y alloy, and Sc,
Th, Ce, La, Ti, Zr, Hf, Nb and Ta
1 to 3 of at least one nitride-forming element selected from
It is preferable to use an alloy having a composition containing 0% by weight and the balance substantially consisting of M element.

Al and Cr are elements responsible for corrosion resistance and oxidation resistance. If the content of Al and Cr is less than the lower limit value of the above range, the corrosion resistance and the oxidation resistance effect of the coating layer are deteriorated and the sufficient function cannot be exhibited. On the other hand, when the content exceeds the upper limit of the above range, the formation of harmful intermetallic compound layers is promoted and the ductility of the coating layer is lowered, so that the life is shortened due to crack growth in the coating layer and the like. A more preferable composition ratio of Al and Cr is 3 to 15 wt% of Al and 15 of Cr.
３５35% by weight.

Y is an element that improves the adhesiveness of the protective oxide film and the coating layer, and if the amount is out of the above range, the effect is reduced. A more preferable composition ratio of Y is in the range of 0.1 to 1% by weight. The balance of the M element may be at least one element selected from Fe, Ni and Co, but in view of compatibility with the base alloy and life, Ni or Co is a single element or Ni and Co. (Ni> Co) or a combination of Co and Ni (Co> Ni) is preferable.

The nitride forming element in the coating layer region containing a high concentration of the nitride forming element is an element that traps nitrogen and suppresses nitriding of Al or the like as described above. If the content of such a nitride-forming element is less than 0.1% by weight, a sufficient nitrogen trapping effect cannot be obtained, and conversely 3
If it exceeds 0% by weight, a harmful phase may be generated and the life of the coating layer may be shortened. The more preferable content of the nitride forming element is in the range of 1 to 20% by weight.

The main constituent of the coating layer is M-Cr-Al-
In the Y alloy layer, Sc, Th, Ce, La, Ti, Zr,
At least one nitride-forming element selected from Hf, Nb, and Ta may be contained, but in order to prevent the nitride from being mainly formed on the base material side, the nitride-forming element is used only. The concentration is lower than that in the high-concentration region. Further, in order to suppress the decrease in ductility of the M-Cr-Al-Y alloy layer, the content of the nitride forming element is set to 5% by weight.
The following is preferable.

The second heat-resistant member according to the present invention is Sc, T
A layer containing at least one nitride-forming element selected from h, Ce, La, Ti, Zr, Hf, Nb and Ta in a higher concentration than the M-Cr-Al-Y alloy which is the main constituent of the coating layer is M-. At least one Cr-Al-Y alloy layer is provided. Similar to the first heat-resistant member, the above-mentioned nitride-forming element is an element whose standard free energy of formation of nitride is lower than that of Al at the operating temperature of the gas turbine of 973 K or higher, for example. Is. Therefore, a layer containing a high concentration of these nitride-forming elements is M
By forming it in the -Cr-Al-Y alloy layer, it is possible to suppress the intrusion of nitrogen into the material and significantly suppress the generation of Al nitrides and the like.

As described above, the nitridation of Al hinders the formation of the protective oxide film and reduces the ductility of the coating layer, which causes the coating layer to be significantly deteriorated. Therefore, M-
Sc, Th, Ce, La, T in the Cr-Al-Y alloy layer
By forming a layer containing a high concentration of at least one nitride-forming element selected from i, Zr, Hf, Nb, and Ta, and trapping nitrogen that has penetrated into the inside of the coating layer with the high concentration layer of a nitride-forming element, Nitriding of Al can be suppressed,
This makes it possible to achieve a long life of the metal coating material in the presence of nitrogen. However, if the above-mentioned nitride-forming element is added to the entire M-Cr-Al-Y alloy layer, the ductility and the like of the coating layer itself may be reduced, and cracking and the like may be promoted.

Therefore, in the second heat-resistant member of the present invention, for example, as shown in FIG.
In the vicinity of the surface of the -Cr-Al-Y alloy coating layer 2, the main M-Cr-Al-Y alloy, that is, M on the base material 1 side, is formed.
An M-Cr-Al-Y alloy layer 2b containing a high concentration of a nitride forming element is formed from the -Cr-Al-Y alloy layer 2a. By adopting such a configuration, a normal M-
The Cr-Al-Y alloy layer 2a provides the original characteristics of the M-Cr-Al-Y alloy, that is, corrosion resistance / oxidation resistance, adhesion to the base material 1, and the like, and further increases the concentration of the nitride-forming element. Including M-
The Cr-Al-Y alloy layer 2b can improve nitriding resistance. Note that M containing a high concentration of a nitride-forming element
The -Cr-Al-Y alloy layer 2b is not always M-Cr-A.
It does not have to be exposed on the surface of the 1-Y alloy layer 2, and may be provided between the coating layer 2a and the base material 1 or inside the coating layer 2a, and at least one 2b is provided. However, it is most preferable for practical use. The thickness of the M-Cr-Al-Y alloy coating layer 2 is preferably about 10 to 300 μm, and the M-Cr-Al containing a nitride forming element in a high concentration.
The thickness of the —Y alloy layer 2b is preferably about 1 to 100 μm, although it depends on the content of the nitride forming element.

Further, the layer containing the nitride forming element in a high concentration contains Cr, Al and Y in the same degree as the above-mentioned main M-Cr-Al-Y alloy, and Sc, T
1 to 30 of at least one kind of nitride-forming element selected from h, Ce, La, Ti, Zr, Hf, Nb and Ta.
It is preferable to use an alloy having a composition containing wt% and the balance substantially consisting of M element.

Al and Cr are elements responsible for corrosion resistance and oxidation resistance. If the content of Al and Cr is less than the lower limit value of the above range, the corrosion resistance and the oxidation resistance effect of the coating layer are deteriorated and the sufficient function cannot be exhibited. On the other hand, when the content exceeds the upper limit of the above range, the formation of harmful intermetallic compound layers is promoted and the ductility of the coating layer is lowered, so that the life is shortened due to crack growth in the coating layer and the like. A more preferable composition ratio of Al and Cr is 3 to 15 wt% of Al and 15 of Cr.
３５35% by weight.

Y is an element that improves the adhesiveness of the protective oxide film and the coating layer, and if the amount is out of the above range, the effect is reduced. A more preferable composition ratio of Y is in the range of 0.1 to 1% by weight. The balance of the M element may be at least one element selected from Fe, Ni and Co, but in view of compatibility with the base alloy and life, Ni or Co is a single element or Ni and Co. (Ni> Co) or a combination of Co and Ni (Co> Ni) is preferable.

The nitride forming element in the coating layer containing a high concentration of the nitride forming element is an element which traps nitrogen as described above and suppresses nitriding of Al or the like. If the content of such a nitride-forming element is less than 0.1% by weight, a sufficient nitrogen trapping effect cannot be obtained, and conversely, if it exceeds 30% by weight, a harmful layer is formed and the coating is performed. The life of the layer may be reduced. The more preferable content of the nitride forming element is in the range of 1 to 20% by weight.

M-Cr-Al- which is the main constituent of the coating layer
In the Y alloy layer, Sc, Th, Ce, La, Ti, Zr,
At least one nitride-forming element selected from Hf, Nb, and Ta may be contained, but in order to prevent the nitride from being mainly formed on the base material side, the nitride-forming element is used only. The concentration is lower than that of the layer containing a high concentration.
Further, in order to suppress the decrease in the ductility of the M-Cr-Al-Y alloy layer, the content of the nitride forming element is preferably 5% by weight or less.

The above-mentioned second heat resistant member is manufactured, for example, as follows. First, M-Cr-Al-Y containing a low concentration or no nitride forming element on a base material made of a heat-resistant alloy containing at least one element selected from Fe, Ni and Co as a main component. The alloy layer is formed by a plasma spraying method, an electron beam PVD method, a CVD method, or the like. Next, M-Cr- containing a high concentration of a nitride-forming element.
The Al-Y alloy layer is formed by the same method. Alternatively, a plasma spray method, an electron beam PVD method, a CVD method, etc. may be used to form
After a Cr-Al-Y alloy layer is formed, this member is embedded in a mixed powder of ammonium chloride and a nitride-forming element powder, and surface-diffusion is enriched with the nitride-forming element powder by a method of surface diffusion. Can also be made.

Next, the third heat resistant member will be described in detail.
The third heat-resistant member is made of Sc, Th, Ce, La, Ti, Zr, Hf, N similarly to the first and second metal coating materials.
An M-Cr-Al-Y alloy containing at least one nitride forming element selected from b and Ta is used as a constituent material of the coating layer.

Then, for example, as shown in FIG.
The r-Al-Y alloy layer 2 is mainly composed of a matrix phase 3 containing an M element as a main component and an intermetallic compound phase 4 containing an M element, an Al element and the above-mentioned nitride forming element.

In the M-Cr-Al-Y alloy layer having the above structure, when nitrogen penetrates into the coating layer, the intermetallic compound layer is decomposed to form a nitride, so that further penetration of nitrogen can be prevented. . Further, since the nitride-forming element is dispersed and arranged as an intermetallic compound phase in the matrix phase containing the M element as a main component, it does not adversely affect characteristics such as ductility of the matrix phase, and the matrix phase Since it itself has high ductility, it is possible to suppress the occurrence of cracks or the like in the M-Cr-Al-Y alloy layer. Furthermore, M-Cr-A
The basic corrosion resistance and oxidation resistance of the l-Y alloy layer can be obtained mainly by the matrix phase.

As the above-mentioned intermetallic compound, for example, M
_{3 X, M 5 X 3,} MX, M 2 X 3, MX 3, M 2 X 9,
_{M 4 X 13, MX 2,} M 2 X 5, M 17 X 2, M 2 X, M 3
X ₇ , M ₅ X (where M is at least one element mainly selected from Fe, Ni and Co, and X is mainly Al and a nitride-forming element) and the like.

The volume ratio of the intermetallic compound phase in the M-Cr-Al-Y alloy layer is preferably in the range of 1-60%. If the volume ratio of the intermetallic compound phase is less than 1%, a sufficient nitrogen trapping effect cannot be obtained, and conversely, if it exceeds 60%, the original characteristics of the M-Cr-Al-Y alloy layer deteriorate. As a result, the life of the coating layer may be shortened. The volume ratio of the intermetallic compound phase is more preferably in the range of 5 to 50%.

M-containing an intermetallic compound phase as described above
For the Cr-Al-Y alloy layer, M-, which is basically used for the metal coating material in the above-mentioned first and second heat resistant members, is used.
An alloy having the same composition as the Cr-Al-Y alloy is used, and the content of the nitride-forming element is set so as to satisfy the volume ratio of the intermetallic compound phase described above. Specifically 1-2
It is preferably in the range of 0% by weight. Further, for example, in order to further improve the oxidation resistance, the amount of Al or Cr is increased to further precipitate another intermetallic compound consisting of the M element and the Al element or the Cr element together with the matrix phase and the MX intermetallic compound phase. You may let me.

The above-mentioned third heat-resistant member is manufactured, for example, as follows. M-Cr-Al- containing a nitride-forming element on a base material made of a heat-resistant alloy containing at least one element selected from Fe, Ni and Co as a main component.
Y alloy layer is plasma sprayed, electron beam PVD, CV
It is formed by the D method or the like, and an intermetallic compound phase is formed at the time of forming this M-Cr-Al-Y alloy layer. Alternatively, M-Cr-
The mixed powder of the Al-Y alloy powder and the intermetallic compound powder as described above may be used as a raw material, and the M-Cr-Al-Y alloy layer may be similarly formed by the plasma spraying method or the like. it can.

In the first, second and third metal coating materials of the present invention, a ceramic layer may be provided as a heat shield layer (outermost coating layer) on the M-Cr-Al-Y alloy layer.
This ceramic layer has the effect of shielding external heat and reducing the temperature rise of the base alloy. The types of ceramics include Si ₃ N ₄ , SiC, Al ₂ O ₃ and Zr.
O ₂ , TiN, A1N, sialon, etc. are exemplified, and any ceramic material may be used, but ZrO ₂ is suitable as the heat shield layer. Further, as a stabilizer of ZrO ₂ , Y ₂ O ₃ , CaO, MgO and the like are used, but among these, Y ₂ O ₃ is most preferable, and Y ₂ O ₃ is particularly preferably 8
Partially stabilized zirconia containing about wt% exhibits extremely excellent characteristics. This ceramic layer usually contains many pores, and the elements on the environment side easily pass through.

Therefore, by utilizing the M-Cr-Al-Y alloy layer of the present invention as the bonding layer of the base material and the ceramic layer, the deterioration of the material due to nitrogen is reduced and the life of the heat shield coating material is extended. Great effect.

Next, a fourth heat resistant member according to the present invention and a method for manufacturing the same will be described. A first heat-resistant member manufacturing method capable of manufacturing a fourth heat-resistant member according to the present invention comprises a base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component, In the method for producing a heat-resistant member comprising at least a metal coating layer formed on the surface of the base material, the coating material is subjected to a heat treatment in an atmospheric atmosphere depressurized by atmospheric pressure, and a surface portion of the metal coating layer is formed. It is characterized by having a step of forming an oxide layer on the side.

Further, the second heat-resistant member manufacturing method capable of manufacturing the fourth heat-resistant member according to the present invention is
In a method for producing a heat-resistant member, which comprises at least a base material made of an alloy containing at least one element selected from Ni and Co as a main component, and a metal coating layer formed on the surface of the base material, the atmospheric pressure is temporarily adjusted. After reducing the pressure to 1 × 10 ³ Pa or less, in an atmosphere in which oxygen is supplied so that the atmospheric pressure is higher than the atmospheric pressure and lower than the atmospheric pressure,
It is characterized in that the heat-resistant coating material is subjected to heat treatment to form an oxide layer on the surface side of the metal coating layer.

The fourth heat-resistant member of the present invention comprises an M-Cr-Al-Y alloy (M is N) on the surface of the alloy base material as described above.
i, Co, and Fe, which represent at least one element). In addition,
A ceramic heat shield layer may be provided as the outermost coating layer on the metal coating layer made of the M-Cr-Al-Y alloy. The ceramics heat shield layer has an effect of shielding outside heat and reducing a temperature rise of the base material.

In the M-Cr-Al-Y alloy layer, 0.
1-20 wt% Al, 10-40 wt% Cr, 0.
It is preferable to use an alloy having a composition containing 1 to 1.5% by weight of Y and the balance substantially consisting of M element.

Al and Cr are elements responsible for corrosion resistance and oxidation resistance. If the contents of Al and Cr are less than the lower limit of the above range, the corrosion resistance and oxidation resistance of the coating layer may be deteriorated and the sufficient function may not be exhibited. On the other hand, if it exceeds the upper limit of the above range, the production of harmful intermetallic compound layers is promoted, and the ductility of the metal coating layer is reduced, so that the life may be shortened due to crack growth in the metal coating layer. . A more preferable composition ratio of Al and Cr is 3 for Al.
˜15 wt% and Cr in the range of 15-35 wt%.

Y is an element that improves the adhesiveness of the oxide layer and the metal coating layer, and the effect is reduced in any case outside the above range. A more preferable composition ratio of Y is in the range of 0.3 to 1% by weight.

The remaining M element may be at least one element selected from Fe, Ni and Co. From the viewpoint of compatibility with the base alloy and life, in particular, a single element of Ni or Co, or Ni and Co (Ni> Co) and Ni (C
The combination of o> Ni) is preferred.

The constituent materials of the ceramics heat shield layer are Si ₃ N ₄ , SiC, Al ₂ O ₃ and ZrO.
Various ceramic materials such as ₂ , TiN, A1N, and sialon are exemplified, and any ceramic material may be used, but ZrO ₂ is particularly preferable. As the stabilizer of ZrO ₂ , Y ₂ O ₃ , CaO, MgO and the like are used, and among these, Y ₂ O ₃ is most preferable, and particularly Y ₂ O.
Partially stabilized zirconia containing about 8% by weight of ₃ shows extremely excellent characteristics.

The metal coating layer made of the above-mentioned M-Cr-Al-Y alloy has an oxide layer on the surface side thereof, and γ'in the range of 5 μm in the thickness direction from the lower portion of the oxide layer.
An initial precipitate consisting of the phase and β phase is present in an area ratio of 10% or more. That is, the heat-resistant coating material of the present invention,
For example, by applying the heat treatment method of the present invention, A
The oxide layer mainly composed of 1-oxide is a dense oxide layer with few internal defects, and M-Cr-Al-Y
It suppresses the partial disappearance of the initial precipitates consisting of the γ'phase and β phase existing on the surface side of the alloy.

Since the above-mentioned dense oxide layer having few internal defects has an effect of inhibiting nitrogen contained in the environment from penetrating into the material, it suppresses the formation of nitride in the metal coating layer and the base material. can do. In addition, M-Cr-
In the vicinity of the surface of the Al—Y alloy layer, that is, in the range of 5 μm in the thickness direction from the lower part of the oxide layer, the partial disappearance of the initial precipitates is suppressed, and the initial precipitates are present in an area ratio of 10% or more. The oxidation rate in the actual environment can be remarkably reduced. Therefore, it becomes possible to prevent deterioration of the oxidation resistance originally possessed by the M-Cr-Al-Y alloy.

Here, in the initial state of the M-Cr-Al-Y alloy layer 3, as shown in FIG.
In the case of i, Ni ₃ Al (γ 'phase) or NiAl (β phase)
Etc. When the M element is Co, CoAl (β phase) and the like, and when the M element is Fe, FeAl (β ₂ phase) and the like are present as the initial precipitates 4. These are all M-Cr-
It is an intermetallic compound phase of Al that is responsible for the oxidation resistance of the Al-Y alloy phase.

Therefore, when the amount of the above-mentioned initial precipitates in the vicinity of the surface of the M-Cr-Al-Y alloy layer becomes 10% or less in area ratio, the M-Cr-Al-Y alloy layer suddenly grows in an actual environment. And the original oxidation resistance of the M-Cr-Al-Y alloy layer is significantly impaired. In order to obtain better oxidation resistance, the amount of initial precipitates in the vicinity of the surface of the M-Cr-Al-Y alloy layer is preferably 30% or more in terms of area ratio.

As will be described in detail later, according to the manufacturing method of the present invention, A in the vicinity of the surface of the M-Cr-Al-Y alloy layer is A.
It is possible to suppress the partial disappearance of the initial precipitate that stores l and form the oxide layer mainly containing Al oxide as described above.

As described above, the oxide layer on the surface of the metal coating layer in the heat-resistant member of the present invention should improve the nitriding resistance without deteriorating the original oxidation resistance of the M-Cr-Al-Y alloy. Is made possible. When the ceramics heat shield layer is formed on the metal coating layer, the above-mentioned oxide layer is formed in the vicinity of the interface between the metal cover layer and the ceramics heat shield layer, and from the bottom of the oxide layer. The amount of initial precipitates in the range of 5 μm in the thickness direction is 10% in area ratio
That is all.

Next, the heat treatment method in the first manufacturing method of the fourth heat-resistant member of the present invention will be described. First, the first manufacturing method includes a step of forming an oxide layer on the surface side of the metal coating layer by subjecting the heat-resistant member on which the metal coating layer is formed to heat treatment in an air atmosphere at a pressure lower than atmospheric pressure. Have

According to such heat treatment, the metal coating layer, for example M, is added under the environment where the oxidation potential is lower than that in the atmosphere.
An oxide layer can be formed on the surface portion side of the -Cr-Al-Y alloy layer. Since the growth rate of this oxide layer is slower than that in the heat treatment in the atmosphere, element diffusion in the M-Cr-Al-Y alloy layer is sufficiently performed. Therefore, as shown in FIG. 4, the above-mentioned Al-containing initial precipitates 4 in the M-Cr-Al-Y alloy layer 3 are uniformly consumed, and the initial precipitates 4 responsible for oxidation resistance are near the surface. It is possible to form a sound and dense oxide layer 5 mainly composed of Al oxide on the surface without being partially depleted in the part.

Here, when the heat treatment for forming the oxide layer is performed at atmospheric pressure, the oxide layer 5 is rapidly formed as shown in FIG. 5, so that the M-Cr-Al-Y alloy layer 3 is formed. The initial precipitates 4 near the inner surface layer are rapidly consumed, and the initial precipitates 4 responsible for the oxidation resistance are partially depleted in the surface vicinity part 6, so that the denseness of the oxide layer 5 decreases. However, the number of internal defects increases, and it is not possible to suppress the penetration of nitrogen into the metal coating layer and the inside of the substrate.

In the conventional heat-resistant member, the base material is damaged due to the formation of the nitride in the metal coating layer and the base material in association with the penetration of nitrogen as described above.

Since the oxide layer formed by the heat treatment method in the first manufacturing method of the present invention is dense and has very few internal defects as compared with the oxide layer formed in the atmosphere, it is included in the environment. It has an excellent deterrent effect on the penetration of nitrogen into the material.

Moreover, M-Cr-Al which stores Al
-By suppressing partial disappearance of the initial precipitates in the Y alloy layer, A
Since it is possible to form an oxide layer mainly containing 1-oxide, it becomes possible to significantly reduce the oxidation rate in an actual environment. With these, a heat resistant coating material having both oxidation resistance and nitriding resistance as described above can be obtained.

[0067] atmospheric pressure in the heat treatment method of the first production method is basically the effect commensurate with the degree of reduced pressure if pressure is reduced below atmospheric pressure can be obtained, especially 3 × 10 ² to 5
It is preferably in the range of × 10 ^-6 Pa. 3 x 10 ²
In an atmosphere exceeding Pa, M elements such as Cr and Ni are contained in the oxide layer, which reduces the effect of inhibiting nitrogen intrusion of the oxide layer. On the contrary, in a high vacuum of less than 5 × 10 ⁻⁶ Pa, the growth rate of the oxide layer is remarkably slow, which significantly reduces productivity and is not realistic.

The conditions for the heat treatment are set as appropriate according to the constituent material of the metal coating layer, the thickness thereof, and the like. For example, the heat treatment at a temperature of 900 to 1300 K for about 10 to 70 hours is performed. It is preferable to carry out. If the heat treatment temperature is too low or the heating time is too short, the amount of oxides may be insufficient, and sufficient nitriding resistance may not be imparted. On the other hand, if the heat treatment temperature is too high, the quality of the oxide layer may deteriorate. On the other hand, if the heating time is too long, the amount of oxide formed may be too large and the original properties of the metal coating layer may be impaired.

In the heat treatment method of the second manufacturing method of the fourth heat-resistant member of the present invention, the atmospheric pressure is once set to 1 × 1.
After reducing the pressure to 0 ³ Pa or less (P ₁ ), the atmospheric pressure P
Atmospheric pressure (P higher than ₁ and lower than atmospheric pressure (P ₀ ).
₂ : In the atmosphere in which oxygen is supplied so that P ₁ <P ₂ <P ₀ , the heat-resistant coating material on which the metal coating layer is formed is subjected to a heat treatment to form an oxide layer on the surface side of the metal coating layer. To form.

According to the heat treatment as described above, similar to the heat treatment in the first manufacturing method, the dense and sound Al oxidation can be performed without partially depleting the initial precipitates responsible for the oxidation resistance in the vicinity of the surface. It is possible to form an oxide layer mainly composed of a substance on the surface, and even in an environment where an oxide and a nitride are formed at the same time because a sufficient degree of vacuum cannot be obtained due to restrictions on the device. Since the subsequent supply of oxygen increases only the oxidation potential in the atmosphere, it is possible to form only the oxide near the surface while preventing the formation of nitrides and the solid solution of nitrogen.

Once the dense and sound oxide layer is formed on the surface, the penetration of nitrogen into the material is extremely suppressed, so that the nitriding resistance of the heat resistant coating material is significantly improved.
In addition, the heat treatment method in the second manufacturing method has an advantage that the heat treatment apparatus itself is inexpensive because it is possible to form an oxide layer having excellent nitriding resistance without significantly lowering the atmospheric pressure during the heat treatment.

At this time, the atmospheric pressure P _{1 is set} to 1 at the initial depressurization.
If the value is set higher than × 10 ³ Pa, the effect of nitrogen cannot be sufficiently eliminated. Further, it is preferable to supply oxygen so that the atmospheric pressure is maintained at 3 × 10 ⁻¹ Pa or less. Atmospheric pressure after oxygen supply is 3
When it exceeds x10 ^-1 Pa, the oxidation potential becomes too high, and an oxide layer other than Al is rapidly formed, so that the denseness is lowered and the internal defects are increased. The heat treatment conditions in the second manufacturing method are preferably the same as those in the first manufacturing method.

The first and second manufacturing methods of the present invention are also effective when the ceramic coating layer is formed on the M-Cr-Al-Y alloy layer. That is, since the ceramic coating layer usually contains many pores and easily allows the elements in the heating atmosphere to pass through, the oxygen in the atmosphere causes M
The oxide layer as described above can be formed on the surface portion side of the —Cr—Al—Y alloy layer.

Furthermore, when the heat treatment of the present invention is applied to a coating material having oxide-based or oxynitride-based ceramics such as Al ₂ O ₃ , ZrO ₂ and sialon on the alloy layer, not only oxygen in the atmosphere but also oxygen in the atmosphere is applied. It is possible to consume oxygen in the ceramic layer to form an oxide layer having excellent characteristics on the surface of the alloy layer, and it is difficult to oxidize due to oxygen in the atmosphere, 2 × 10 ⁻⁴ Pa or more Even in the high vacuum region, the oxide layer can be formed by the latter mechanism. Among the above-mentioned oxide and oxynitride-based ceramics, ZrO ₂ or oxygen is dissolved in a large amount, and dissociation is easy. Therefore, it is most suitable as an oxygen supply source in the production method of the present invention. Further, since the ceramic coating layer easily allows passage of elements in the environment, by forming an oxide layer with improved nitriding resistance by the manufacturing method of the present invention,
It is possible to achieve a long life of the thermal barrier coating material.

The first and second manufacturing methods of the present invention are not limited to the metal coating layer made of the M-Cr-Al-Y alloy as described above, but may be applied to the metal coating layer formed by the so-called aluminum pack method. It is valid.

That is, in a mixed powder of a metal powder containing Al and an additive such as ammonium chloride or an aluminum oxide powder as a sintering inhibitor, or in vapor generated from this mixed powder, the base material or M-Cr- A base material coated with an Al-Y alloy layer is placed, and 873-14 in a hydrogen atmosphere.
By heating to a temperature of about 73 K, an Al coating layer is formed as a metal coating layer on the base material or the M-Cr-Al-Y alloy layer. The Al coating layer formed by the aluminum pack method is basically composed of a compound of Al and NiCo, Fe or the like.

By applying the first or second heat treatment method of the present invention to the heat resistant coating material having the Al coating layer as described above, the metal coating layer becomes M-Cr-A.
As in the case of using only the l-Y alloy layer, a dense oxide layer with few internal defects can be formed on the surface side of the Al coating layer. This makes it possible to impart both oxidation resistance and nitriding resistance.

Further, the heat treatment methods according to the first and second production methods of the present invention can be used not only as a method for producing the heat resistant coating material of the present invention and the heat resistant coating material using the aluminum pack method described above, but also For example, the heat treatment of the present invention can be applied at the time of repairing a component for thermal equipment such as a gas turbine blade. That is, by performing the heat treatment of the present invention at the time of repairing a component for a thermal device, it is possible to re-form an oxide layer mainly composed of a dense Al oxide that cannot be obtained in a combustion gas atmosphere of a gas turbine or the like. This makes it possible to prolong the service life of parts for thermal equipment such as gas turbine blades.

[0079]

Embodiments of the present invention will be described below. Example 1 First, a Ni-based alloy IN738LC was prepared as a base material. After cutting this substrate into a size of 20 × 20 × 5 mm,
Surface roughening treatment with alumina particles (sandblasting)
I went. Then, Ni-22% Co-1 was formed on this substrate.
An alloy powder having a composition of 7% Cr-12% Al-0.6% Y (wt%) was plasma sprayed under reduced pressure to a thickness of about 150 μm. Furthermore, Ni-21% Co-17% on it
An alloy powder having a composition of Cr-12% Al-1.5% Sc-0.6% Y (wt%) was plasma sprayed under reduced pressure to a thickness of about 50 μm, and Sc was used as a nitride forming element on the surface side.
(Ni, Co) -Cr-A having a layer containing a high concentration of
An I-Y alloy layer was formed. In this way, the intended metal coating material was produced and subjected to the characteristic evaluation described later.

As a comparative example with the present invention, Ni-22% Co-17% Cr-on the same substrate as in Example 1 above.
About 12% Al-0.6% Y (wt%) composition powder only
Sample of low pressure plasma spraying with a thickness of 00 μm (Comparative Example 1
A) was prepared and subjected to characteristic evaluation. In addition, Ni-based alloy I
A sample of N738LC alone (Comparative Example 1B) was also subjected to the characteristic evaluation in the same manner.

Each test piece of Example 1 and Comparative Example 1 described above was first subjected to a pure nitrogen gas flow (5 × 10 ⁻³ m ³ / mi).
In n), a heat treatment of 1273K × 500h was performed. After the heat treatment, the cross section of the test piece was observed by SEM to measure the thickness of the nitride layer formed inside. As a result, in Comparative Example 1A, the coating layer was 55 μm, and in Comparative Example 1B, 150 μm.
Each μm nitride layer was observed. On the contrary,
In Example 1, only the nitride layer having a thickness of 9 μm was observed, and it was found that the coating layer according to the present invention can impart the nitriding resistance property to the member and achieve the long life of the member.

Example 2 Instead of the two-layer M-Cr-Al-Y alloy layer in Example 1, the M-Cr-Al-Y alloy whose composition is shown in Table 1 and the nitride-forming element-containing M- A metal coating material was produced under the same conditions as in Example 1 except that the Cr-Al-Y alloy was used. Comparative Example 2 is also M-Cr-Al containing a nitride forming element.
It is the same except that the -Y alloy is not used. Example 2
The nitriding resistance of the metal coating material according to Comparative Example 2 was measured in the same manner as in Example 1. The results are also shown in Table 2 as the thickness of the nitride layer.

[0083]

[Table 2]

Example 3 A Ni-base alloy IN738LC was prepared as a base material, and Ni-22% Co-17% Cr-12% Al- was formed on the surface of the base material.
An alloy powder having a composition of 1.5% Zr-0.6% Y (wt%) was sprayed under reduced pressure to a thickness of about 200 μm. As a result of identifying the produced phase in the obtained coating phase by XRD, the (Al, Zr) Ni ₃ phase was confirmed together with the NiAl phase. The matrix phase was a phase containing Ni and Co as main components. In this way, the metal coating material having the M (Ni, Co) -Cr-Al-Y alloy layer containing the intermetallic compound phase was prepared and provided for the characteristic evaluation described later.

As a comparative example with the present invention, Ni-22% Co-17% Cr-12% Al-on the same base material.
Approximately 200μ only for alloy powder with 0.6% Y (wt%) composition
A sample (Comparative Example 3) having a thickness of m and subjected to low pressure plasma spraying was prepared and subjected to the same characteristic evaluation.

Each of the test pieces of Example 3 and Comparative Example 3 described above was first subjected to a pure nitrogen gas flow (5 × 10 ⁻³ m ³ / mi).
In n), a heat treatment of 1273K × 500h was performed. When the cross section of the test piece was observed by SEM after the heat treatment, a nitride layer of 55 μm from the surface was observed in Comparative Example 3, but only a 2 μm nitride layer was observed in Example 3.

Example 4 In place of the M-Cr-Al-Y alloy in Example 3, the nitride forming element-containing M-Cr-A whose composition is shown in Table 2 is used.
A metal coating material was produced under the same conditions as in Example 3 except that the I-Y alloy was used. The produced phase (compound phase) in the coating phase of these metal coating materials was identified by XRD, and the nitriding resistance was measured in the same manner as in Example 3. The results are also shown in Table 3 as the thickness of the nitride layer.

[0088]

[Table 3]

Example 5 A Ni-base alloy IN738LC was prepared as a base material, and an alloy powder having a composition of Co-29% Cr-6% Al-0.4% Y (wt%) was formed on the base material to a thickness of about 150 μm. Low pressure plasma spraying so that Co-29% Cr-6% A
An alloy powder having a composition of 1-10% Hf-0.4% Y (weight%) was sprayed under reduced pressure to a thickness of about 50 μm.
Further, on the M (Co) -Cr-Al-Y alloy layer,
8% Y ₂ O ₃ —ZrO ₂ powder was plasma sprayed in the atmosphere to a thickness of about 200 μm. Thus, M (C) having a layer containing Hf at a high concentration as a nitride forming element
o) A metal coating material in which a ceramics heat shield layer was formed on a -Cr-Al-Y alloy layer was prepared and subjected to the characteristic evaluation described later.

As a comparative example with the present invention, only alloy powder of Co-29% Cr-6% Al-0.4% Y (wt%) composition was depressurized to a thickness of about 200 μm on the same substrate. Sample which was plasma sprayed and on which 8% Y ₂ O ₃ —ZrO ₂ powder was plasma sprayed to a thickness of 200 μm in air (Comparative Example 4).
Was prepared and subjected to characteristic evaluation in the same manner.

Each of the test pieces of Example 5 and Comparative Example 4 described above was first subjected to a pure nitrogen gas flow (5 × 10 ⁻³ m ³ / mi).
In n), a heat treatment of 1273K × 500h was performed. When the cross section of the test piece was observed by SEM after the heat treatment, a nitride layer of 120 μm was observed in the metal coating layer in Comparative Example 4, but only a nitride layer of 7 μm was observed in Example 5. As a result, it was found that the effect of the metal coating layer according to the present invention is extremely large even when the ceramics heat shield layer is formed.

Example 6 First, a Ni-base alloy IN738LC was prepared as an alloy base material, and this base material was cut into a specimen size of 20 × 20 × 5 mm. Then, the surface of the base material in the shape of the test piece was subjected to surface roughening treatment (sandblasting treatment) with alumina particles. Then, Co-29% Cr-6% Al was applied to the roughened surface of the base material by using a reduced pressure plasma spraying method (VPS).
A 0.4% Y alloy (% by weight) was coated to a thickness of about 200 μm.

Next, the base material on which the Co-Cr-Al-Y alloy layer is formed is placed in a vacuum heating furnace and the inside of the furnace is set to 1.5 ×.
After evacuation to 10 ^-4 Pa, heat treatment is carried out under the condition of 1393K × 2h as strength recovery heat treatment for the base material, then cooled to 1123K while maintaining the above vacuum degree, and heat treatment at that temperature for 24 hours, that is, the main A heat treatment was applied to which the first method of the invention was applied. Then, it cooled to normal temperature and obtained the heat resistant coating material of this invention. This heat resistant coating material was subjected to the characteristic evaluation described later.

Further, as a comparative example with the present invention, a coating material which is not subjected to heat treatment after the above-mentioned thermal spraying (Comparative Example 5).
And a coating material (Comparative Example 6) in which the heat treatment after the above-mentioned thermal spraying was carried out in a still atmosphere (the temperature and time were the same as those in Example 6) were prepared and subjected to the characteristic evaluation described later.

In order to examine the nitriding resistance of each test piece according to Example 6 and Comparative Examples 5 and 6, 1273 was applied to each test piece.
A heating test was performed for 500 hours in a pure nitrogen gas flow of K. Then, after this heating test, the structure of the cross section of each test piece was observed to measure the thickness of the nitride layer (A1N and TiN).

As a result, in the test piece of Comparative Example 5, the formation of nitride was the most remarkable among the three kinds of test pieces.
Nitride was formed throughout the -Al-Y alloy layer, and further, nitride was observed inside the substrate up to a depth of 50 µm from the interface between the Co-Cr-Al-Y alloy layer and the substrate. Further, in the test piece of Comparative Example 2, no nitride was observed inside the base material, but a nitride layer having a thickness of 130 μm was observed inside the Co—Cr—Al—Y alloy layer.

On the other hand, in the test piece according to Example 6, no nitride was found not only inside the substrate but also inside the Co—Cr—Al—Y alloy layer, and the first sample of the present invention was applied after the thermal spraying. It was shown that the heat treatment based on the heat treatment method is extremely effective in improving the nitriding resistance. In order to investigate the cause, the surface oxide was identified by X-ray diffraction. As a result, the oxide layer of Comparative Example 6 was found to have Cr ₂ O ₃ or CrO ₃ and N
Whereas it was composed of a composite oxide of i, Co, Al and Cr, only Al ₂ O ₃ was identified in the oxide layer according to Example 6.

From the above, by performing the heat treatment in the low oxygen potential of the present invention, only Al, which has the highest affinity for oxygen, selectively forms an oxide, and the formation rate thereof is extremely slow. It was found that an Al ₂ O ₃ layer containing no impurities was formed, and this surface oxide layer provided excellent nitriding resistance.

In each of the test pieces of Example 6 and Comparative Example 6, the thickness direction was 5 μm from the bottom of the oxide layer.
When the amount of the initial precipitates in the range of 4 was measured by scanning electron microscope observation, the test piece of Example 6 had 42% of the initial precipitates in the area ratio, whereas the test piece of Comparative Example 6 had the initial precipitates. The precipitate was consumed up to an area ratio of 0.7%.
From this, it can be seen that the test piece according to Example 1 maintains the original oxidation resistance.

Example 7 An Ni base alloy IN738LC was prepared as an alloy base material, and this base material was cut into a specimen size of 20 × 20 × 5 mm. Then, the surface of the base material in the shape of the test piece was subjected to surface roughening treatment (sandblasting treatment) with alumina particles. After that, a low pressure plasma spraying method (V
PS-), Co-29% Cr-6% Al-0.4
% Y alloy (wt%) was coated to a thickness of about 200 μm.

Next, the base material on which the Co-Cr-Al-Y alloy layer is formed is placed in a vacuum heating furnace, and the inside of the furnace is temporarily set to 1.
After vacuuming to 2 × 10 ^-4 Pa, the atmospheric pressure is 8.6.
Pure oxygen was supplied so that the pressure became × 10 ⁻³ Pa, and the heat treatment for strength recovery of the base material was performed in this atmosphere under the condition of 1393 K × 2 h, and then 1 while keeping the above vacuum degree.
It was air-cooled to 123K and heat-treated at that temperature for 24 hours, that is, the heat treatment to which the second method of the present invention was applied.
Then, it was air-cooled to room temperature to obtain the heat resistant coating material of the present invention. This heat resistant coating material was subjected to the characteristic evaluation described later.

As a comparative example with the present invention, a coating material (Comparative Example 7) in which the heat treatment after the thermal spraying was carried out in the static atmosphere (temperature and time were the same conditions as in Example 7) was prepared, and described later. Was subjected to the characteristic evaluation.

In order to examine the nitriding resistance of each test piece according to Example 7 and Comparative Example 7, each test piece was subjected to a heating test for 500 hours in a pure nitrogen gas flow of 1273K. Then, after this heating test, the structure of the cross section of each test piece was observed to measure the thickness of the nitride layer (A1N and TiN).

As a result, in the test piece of Comparative Example 7, C
A 130 μm-thick nitride layer was observed inside the o-Cr-Al-Y alloy layer. On the other hand, in the test piece according to Example 7, no nitride was found not only inside the base material but also inside the Co—Cr—Al—Y alloy layer, which was based on the second method of the present invention applied after thermal spraying. It was shown that the heat treatment is extremely effective in improving the nitriding resistance.

Further, in each of the test pieces of Example 7 and Comparative Example 7, the thickness direction was 5 μm from the lower part of the oxide layer.
When the amount of the initial precipitates in the range of 10 was measured by scanning electron microscope observation, the test piece of Example 7 had 53% of the initial precipitates in area ratio, whereas the test piece of Comparative Example 7 had the initial precipitates. The precipitate was consumed up to 1.3% in area ratio. From this, it can be seen that the test piece according to Example 7 maintains the original oxidation resistance.

Example 8 A Ni-base alloy IN738LC was used as a base material, and the surface of the base material was coated with a Co-29% Cr-6% Al-0.4% Y alloy (weight%) by a low pressure plasma spraying method (thickness). : About 200μ
m) gas turbine rotor blades, and
Heat treatment in a vacuum of 1.5 × 10 ⁻⁴ Pa (condition: 1393K × 2h → cooling + 1123)
K × 24 h → cooling).

As a comparative example with the present invention, a heat treatment (heating conditions are the same as those in Example 8) was applied to the above-mentioned gas turbine rotor blades in a static atmosphere only during manufacturing (Comparative Example 8). A sample (comparative example 9) which was subjected to heat treatment (heating conditions are the same as those in Example 8) in still air at the time of manufacture and at the time of periodic inspection every 6000 hours of operation was prepared.

After each turbine blade according to Example 8 and Comparative Examples 8 and 9 was used for 18000 hours, its cross section was cut and the structure was observed with an optical microscope. As a result, in the gas turbine blade of Comparative Example 8, a nitride layer of 270 μm on average was observed from the base material / metal coating layer interface to the inside of the base material. Further, in the gas turbine blade of Comparative Example 9, a nitride layer having an average thickness of 130 μm was observed inside the base material.

On the other hand, in the gas turbine rotor blade according to Example 8, 60 μm from the surface only inside the metal coating layer.
It was found that the nitriding resistance of the gas turbine blade was significantly improved by applying the repair method based on the heat treatment method of the present invention.

Example 9 A Ni-base alloy IN738LC was prepared as an alloy base material, and this base material was cut into a test piece of 20 × 20 × 5 mm.
Next, the surface of the base material in the shape of the test piece was sandblasted with alumina particles. After that, using a low pressure plasma spraying method (VPS) on the roughened surface of the substrate,
A Co-29% Cr-6% Al-0.4% Y alloy (wt%) was coated to a thickness of about 200 μm. Further, a ZrO ₂ —Y ₂ O ₃ layer having a thickness of about 210 μm was formed as an outermost surface layer on the Co—Cr—Al—Y alloy layer by an atmospheric plasma spraying method.

Next, the above sample was placed in a heating furnace, heat-treated in an inert gas under the condition of 1473K × 2 h, and then continuously in a vacuum of 2.4 × 10 ⁻⁴ Pa, 1123K ×.
Heat treatment was performed for 24 hours. After this, air cool to room temperature,
A heat resistant coating material of the present invention was obtained. This heat resistant coating material was subjected to the characteristic evaluation described later.

As a comparative example with the present invention, 1123
A final heat treatment of K × 24 h was carried out in still air (temperature and time were the same as in Example 6) for coating material (Comparative Example 1).
0) was prepared and subjected to the characteristic evaluation described later.

In order to examine the nitriding resistance of each test piece according to Example 9 and Comparative Example 10 described above, 1273K was applied to each test piece.
Was subjected to a heating test for 500 hours in a stream of pure nitrogen gas.
Then, after this heating test, the structure of the cross section of each test piece was observed to measure the thickness of the nitride layer (A1N and TiN).

As a result, in the test piece according to Comparative Example 10,
While a nitride layer having a thickness of 80 μm was observed inside the Co—Cr—Al—Y alloy layer, the test piece according to Example 9 had a thickness of 5 μm inside the Co—Cr—Al—Y alloy layer. Only the nitride layer was observed.

Example 10 A Ni-base alloy IN738LC was prepared as an alloy base material, and this base material was cut into a specimen size of 20 × 20 × 5 mm. After that, the above-mentioned base material was replaced with Fe-Al alloy and ammonium chloride
It was embedded in a mixed powder with aluminum oxide and subjected to a diffusion and permeation treatment of 1173 K × 2 h in a hydrogen atmosphere to form a NiAl layer having a thickness of 56 μm on the surface.

Next, the above sample was placed in a heating furnace, and 2.
A heat treatment of 1173 K × 30 h was performed in a vacuum of 4 × 10 ⁻⁴ Pa. Then, it was air-cooled to room temperature to obtain the heat resistant coating material of the present invention. This heat resistant coating material was subjected to the characteristic evaluation described later. In addition, a coating material (Comparative Example 11) prepared in the same manner except that the heat treatment was not performed in vacuum was subjected to the characteristic evaluation described below.

In order to examine the nitriding resistance of each test piece according to the above-mentioned Example 10 and Comparative Example 11, 1273 was applied to each test piece.
A heating test was performed for 500 hours in a pure nitrogen gas flow of K. After this heating test, the cross-section structure of each test piece was observed by SEM to measure the thickness of the nitride layer.
As a result, a 53 μm thick nitride layer was observed in the test piece of Comparative Example 11, whereas only a 7 μm thick nitride layer was observed in the test piece of Example 5. From this, it became clear that the heat treatment method of the present invention contributes to the improvement of the nitriding resistance of the metal coating layer by the aluminum pack coating method.

[0118]

As described above, the first, second and third heat resistant members according to the present invention are M-Cr-Al-Y.
Since the alloy layer has a high nitrogen trapping effect, the deterioration of the base material and the metal coating layer due to nitriding can be significantly suppressed, and the life can be remarkably extended. Therefore, even in an environment where oxidation and nitriding, and stress are superimposed on the material, such as the usage environment of a gas turbine blade, excellent corrosion resistance, oxidation resistance, nitriding resistance, and high temperature strength can be obtained for a long time. It is possible to provide a metal coating material that can be maintained over the entire length.

Furthermore, according to the first and second methods for manufacturing a heat-resistant member of the present invention, it is possible to form a dense oxide layer having few internal defects while suppressing partial disappearance of initial precipitates on the surface side. It can be formed on the surface side of the metal coating layer. This makes it possible to remarkably suppress material deterioration due to nitriding without deteriorating the original oxidation resistance of the metal coating layer, thus greatly contributing to the long life of the heat resistant coating material.

According to the fourth heat resistant member of the present invention,
For example, even in an environment in which oxidation and nitriding simultaneously act at a high temperature, such as an environment in which a gas turbine blade is used, excellent oxidation / nitriding resistance can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration example of a second heat resistant member of the present invention.

FIG. 2 is a cross-sectional view schematically showing a configuration example of a third heat resistant member of the present invention.

FIG. 3 is a cross-sectional view schematically showing a dispersed state of initial precipitates in the heat resistant member metal coating layer.

FIG. 4 is a sectional view schematically showing a dispersed state of initial precipitates when the heat-resistant member shown in FIG. 3 is heat-treated by the manufacturing method of the present invention.

5 is a sectional view schematically showing a dispersed state of initial precipitates when the heat-resistant member shown in FIG. 3 is heat-treated in the atmosphere.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... M-Cr-Al-Y alloy coating layer 2a ... M-Cr-Al-Y alloy layer 2b ... M-Cr-Al- containing a nitride forming element in high concentration.
Y alloy layer 3 ... Matrix phase (M-Cr-Al-Y alloy layer) 4 ... Intermetallic compound phase containing a nitride forming element (initial precipitate) 5 ... Oxide layer 6 ... Surface vicinity part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuhiro Yasuda Kazuhiro Yasuda 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Kanagawa Prefecture R & D Center, Ltd. (72) Inventor Masako Nakahashi Komukai-Toshiba, Kawasaki-shi, Kanagawa Town No. 1 Incorporated Corporate Toshiba Research and Development Center (72) Inventor Hiroshi Tateishi No. 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Incorporated Corporate Toshiba Research and Development Center

Claims (13)

[Claims] 1. A base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component,
A heat-resistant member comprising an M-Cr-Al-Y alloy layer coated on the surface of the base material (where M represents at least one element selected from Fe, Ni and Co), wherein the M-Cr The -Al-Y alloy layer includes Sc, Th, Ce,
A heat-resistant member comprising a region containing a high concentration of at least one kind of nitride-forming element selected from La, Ti, Zr, Hf, Nb and Ta. 2. A base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component,
A heat-resistant member comprising an M-Cr-Al-Y alloy layer coated on the surface of the base material (where M represents at least one element selected from Fe, Ni and Co), wherein the M-Cr In the vicinity of the surface of the -Al-Y alloy layer, Sc,
Th, Ce, La, Ti, Zr, Hf, Nb and Ta
At least one nitride-forming element selected from the above M
A heat-resistant member comprising a layer containing a higher concentration than a -Cr-Al-Y alloy. 3. A base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component,
A heat-resistant member comprising an M-Cr-Al-Y alloy layer coated on the surface of the base material (where M represents at least one element selected from Fe, Ni and Co), wherein the M-Cr The -Al-Y alloy layer includes Sc, Th, Ce,
A matrix phase containing at least one nitride forming element selected from La, Ti, Zr, Hf, Nb and Ta, and having the M element as a main component; and the M element dispersedly arranged in the matrix phase, A heat resistant member, which is mainly composed of an intermetallic compound phase containing an Al element and the nitride forming element. 4. A base material made of an alloy whose main component is at least one element selected from Fe, Ni and Co.
A heat-resistant member comprising at least a metal coating layer formed of an M-Cr-Al-Y alloy (where M represents at least one element selected from Ni, Co and Fe) coated on the surface of the base material. In the above, the metal coating layer has an oxide layer on the surface side thereof, and the initial precipitates are present in an area ratio of 10% or more in the range of 5 μm in the thickness direction from the lower portion of the oxide layer. Heat resistant material 5. The heat resistant member according to claim 12, wherein the initial precipitate is an intermetallic compound of Al. 6. The heat-resistant member according to claim 12, wherein the oxide layer is mainly composed of Al ₂ and O ₃ . 7. The heat resistant member according to claim 1, claim 2, claim 3 or claim 4, wherein a ceramic layer is further provided as a heat shield layer on the M—Cr—Al—Y alloy layer. A heat resistant member characterized by the above. 8. A base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component,
In the method for producing a heat-resistant member including at least a metal coating layer formed by coating on the surface of the base material, the heat-resistant member is subjected to heat treatment in an atmosphere depressurized below atmospheric pressure to oxidize the surface of the metal coating layer. A method for producing a heat-resistant member, comprising the step of forming a layer. 9. The method for producing a heat-resistant member according to claim 15, wherein the atmospheric pressure is in the range of 3 × 10 ² to 5 × 10 ⁻⁶ Pa. 10. The method of manufacturing a heat-resistant member according to claim 15, wherein the heat treatment temperature is in the range of 900 to 1300K. 11. A heat-resistant member comprising at least a base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component, and a metal coating layer formed on the surface of the base material. In the method, after holding the heat resistant member in an atmosphere pressure reduced to 1 × 10 ³ Pa or less, oxygen is supplied so that the atmosphere pressure is higher than 1 × 10 ³ Pa and lower than atmospheric pressure,
A method for producing a heat-resistant member, comprising the step of subjecting the heat-resistant member to a heat treatment to form an oxide layer on the surface side of the metal coating layer. 12. The method for manufacturing a heat-resistant member according to claim 18, wherein the pressure of the oxygen-supplied atmosphere is 3 × 10 ⁻¹ P.
a or less. 13. A hydrogen atmosphere in which a base material made of an alloy containing at least one element selected from Fe, Ni and Co as a main component is immersed in a mixed powder of Al-containing metal powder, ammonium chloride and aluminum oxide, and a hydrogen atmosphere. And a heat treatment is performed in an atmosphere pressure lower than atmospheric pressure to form an oxide layer on the surface side of the metal coating layer. A method for manufacturing a heat resistant member.