JPH04143262A - Ceramic coated heat resistant member - Google Patents

Abstract

PURPOSE:To obtain a ceramic coated heat resistant member having thermal shock, corrosion and oxidation resistances and high adhesion by filling a heat resistant substance such as a metal or alloy into the pores in a thermally sprayed ceramic film of molten particles having a laminated structure formed on the surface of a substrate. CONSTITUTION:When a thermally sprayed ceramic film of molten particles having a laminated structure is formed on the surface of a substrate to obtain a heat resistant coated member, the substrate is made of a heat resistant alloy based on Fe, Co or Ni, Cu, a Cu alloy, etc., and a heat resistant substance is filled into the pores in the ceramic film. Ceramic such as SiO2, Al2O3, ZrO2 or a mixture thereof, a metal such as Cu, Ni or Co or an alloy of such metals is suitable for use as the heat resistant substance. The filled substance may be changed over in the thickness direction of the film or the rate of filling may be varied in the thickness direction. A ceramic coated heat resistant member suitable for use as the moving blade of a gas turbine, etc., is obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermal sprayed ceramic coating used for parts and parts exposed to high temperatures, such as moving blades and stationary blades of gas turbines, or combustors of rocket engines. The present invention relates to a heat-resistant composite member having the following properties.

[Conventional technology]

In the fields of gas turbines, aerospace, and nuclear fusion reactors, the development of super heat-resistant materials with excellent heat resistance, heat shielding properties, environmental resistance, etc. is an important technical issue.

Conventionally, one of the methods for manufacturing such super heat-resistant materials is
A typical example is the coating of ceramics on the surface of metals and alloys by plasma spraying, which improves corrosion and oxidation resistance on the surface of heat-resistant superalloy substrates based on Ni, Co, Fe, etc. , ZrO□ through an intermediate layer for the purpose of improving adhesion and alleviating thermal stress.
A method of thermal spraying ceramics such as Y2O3 has been proposed, and as described in JP-A-62-156938, an intermediate layer is provided between the base material and the ceramics in which the ratio of the components of the two continuously changes. Functionally graded material (F) that relieves stress
GM) etc. are known.

[Problem to be solved by the invention]

In the above conventional technology, the surface ceramic layer formed by thermal spraying forms a laminated structure of thermally sprayed flat particles 2 on a base material 1 as shown in FIG. 1, and has many voids 3 between the particles.
It becomes a porous membrane containing.

Therefore, compared to combustion ceramics, the strength of the ceramic layer decreases depending on the content of voids 3, and due to thermal stress caused by the temperature gradient under the usage conditions and the difference in thermal expansion between the base material and the intermediate layer. Cracks and peeling are likely to occur.

In addition, even when thermal stress is alleviated by the intermediate layer or the FGM mentioned above, the ceramic layer may be compressed at high temperatures due to partial heating or cooling of the base material, resulting in a temperature difference between the front and back surfaces. When stress is applied, the voids in the ceramic layer are filled and relaxation occurs, which induces tensile stress and cracks upon cooling. Furthermore, when high-temperature atmospheric gas enters through these voids and cracks, the metal components of the base material and intermediate layer may be corroded or oxidized, resulting in peeling or breakage of the film.

The present invention solves the problems in the prior art described above,
The object of the present invention is to provide a heat-resistant ceramic coated member that has high thermal shock resistance, corrosion resistance, oxidation resistance, and adhesion to a base material.

[Means to solve the problem]

In order to achieve the above object, the inventors of the present invention have conducted extensive research and found that the voids in a fused ceramic film can be densified by filling the voids with ceramics or metals using sol-gel impregnation, electroplating, etc. The present inventors have discovered that it is possible to improve the strength and adhesion of ceramic sprayed coatings, and impart corrosion and oxidation resistance to them, leading to the completion of the present invention.

That is, in a heat-resistant coating member in which a ceramic sprayed coating having a laminated structure of molten particles is provided on the surface of a heat-resistant member, some or all of the voids between particles or within particles are
The gist is a ceramic-coated heat-resistant member characterized by being filled with a heat-resistant material.

[For production]

The structure and operation of the present invention will be explained.

As the base material of the heat-resistant composite material in the present invention, for example, C
U, Ni alloy, CO-based alloy, etc. are used. Further, as the material of the ceramic sprayed layer, for example, ZrO□-M
gO, Zr0z-CaO, Zr0z-Y20s, etc. are suitable.

To fill the voids with ceramics, ethyl orthosilicate solution (TEOS) or aluminum phosphate solution (MAP) is vacuum impregnated into the voids of the sprayed coating, and then fired to form 5s02 and A1.0. A sol-gel method is used to fill the voids with.

In addition, as a filling method for metal, in an electrolytic solution containing the metal ions to be filled, the material is surrounded by a water-impermeable insulator such as silicone rubber so that the electrolyte contacts the base material only through the gaps in the sprayed layer. An electroplating method is used in which electroplating is performed while the material is covered with a material to fill the voids.

In the heat-resistant ceramic spray coating of the present invention, the voids in the ceramic layer are filled with another substance, so the strength and Young's modulus of the ceramic layer are improved, and accordingly, the thermal shock resistance can be improved. In addition, by selecting metals, alloys, or ceramics with excellent corrosion and oxidation resistance as the filler material, high-temperature combustion gas permeates and diffuses through the voids in the ceramic layer, corroding the metal components of the base material and intermediate layer. Alternatively, it can prevent oxidation and exhibit excellent corrosion and oxidation resistance. Furthermore, if the same metal as the base material is selected as the filling material in the electroplating method, the filling material will integrate with the base material and fill the voids, acting as a so-called anchor and improving the adhesion of the coating ink layer. improves.

〔Example〕

The invention will be illustrated by examples without the intention being to limit it thereto.

Example 1 As shown in FIG. 2, CoNlCrA with a thickness of 100 μm was deposited as a bonding layer on a base material l of Ni-based alloy with a thickness of 3.5 mm.
ZrO□-6wt% Y2O3 film 5 through IY alloy layer 4
TE01 (Tetra Eitxl 0rth
o 5ilicate: Immerse in 5i(OC2H6)4) solution to impregnate the voids in the ceramic layer with TEO3 solution. After that, it was heated to 400°C in the atmosphere in an electric furnace.
TE01 is converted to SiO□6 by a hydrolysis reaction. Since volumetric shrinkage occurs during firing, the impregnation and firing process in vacuum is repeated in order to completely fill the voids with SiO□6. The filling condition is determined by measuring the change in weight of the sample every time firing is completed, and the filling is considered complete when the weight increases or almost disappears. In this way, a heat-resistant ceramic spray coating was obtained in which the voids in the ceramic layer were filled with SiO□6.

Next, the thermal shock resistance was evaluated for the ceramic sprayed coating in which the voids obtained by the above method were filled with SiO□ and for comparison, the ceramic sprayed coating that was not filled with 5102.

At this time, the test piece was 9 x 9 aum, and while cooling the back side of the test piece with water via a copper holder, the center of the sample surface was
It was partially irradiated and heated with a 0 kW xenon arc lamp, and about 5 seconds after the temperature at the center of the surface reached a constant temperature, the irradiation was stopped and rapidly cooled. Thereafter, the sample surface and cross section were observed to check for the occurrence of cracks and peeling near the interface. As a result,
Ceramic sprayed coatings that were not filled with SiO□ showed cracks and peeling at the center when the temperature at the center of the surface exceeded approximately 700°C, but samples that were filled with SiO No cracks or peeling were observed, and it was confirmed that thermal shock resistance could be significantly improved.

Example 2 As shown in FIG. 4, lro□-
A 6 wt% Y2O3 film 5 was formed to a thickness of 3 by plasma spraying.
After forming the ceramic layer 5 with a thickness of 00 μm, as shown in FIG. 3, a conductive wire 8 is attached to the back surface of the copper base material 1 by soldering or the like, and the parts other than the surface of the ceramic layer 5 are covered with a water-impermeable insulator 7 such as silicone rubber. do. This is immersed in an aqueous solution containing copper ions, for example, a copper sulfate electrolyte 10 (= immersed in the electrolyte, and the electrolyte is sufficiently permeated into the voids in the ceramic layer 5 by vacuum impregnation, etc., and then a direct current is applied between it and the copper electrode 9. Electrolytic plating is performed by applying voltage 11 to deposit copper 12 in the voids.At this time,
Good filling results can be obtained by controlling the voltage so that the current density is below 0.5 mA/al. In this way, a heat-resistant ceramic sprayed coating was obtained in which some of the voids in the ceramic layer were filled with copper 12, as shown in FIG.

Next, Example 1 was prepared for a ceramic sprayed coating in which the voids obtained by the above method were filled with copper, and for comparison, a ceramic sprayed coating that was not filled with copper.
Thermal shock resistance was evaluated in the same manner as above.

As a result, when the temperature at the center of the surface exceeded approximately 700°C, cracks appeared in the center and the coating peeled off in the ceramic sprayed coating that had not been filled with copper, but with the coating that had been filled with copper. No cracking or peeling was observed in the ceramic sprayed coating up to about 800°C, and it was confirmed that the thermal shock resistance and adhesion were significantly improved.

Example 3 As shown in FIG.
Zr026wt%Y20. The film 5 has a thickness of 300. cz
After forming the ceramic layer by plasma spraying, as shown in FIG. 3, conductive wires 8 are attached to the back surface of the Ni-based alloy base material 1 by soldering, etc., and the parts other than the surface of the ceramic layer '5 are covered with water-impermeable material such as silicone rubber. It is coated with a magnetic insulator 7. This is N
After immersing the ceramic layer in an electrolytic solution containing i ions, such as a nickel sulfate electrolytic solution 10, and allowing the electrolytic solution to sufficiently penetrate into the voids in the ceramic layer by vacuum impregnation or the like, a DC voltage 11 is applied between the ceramic layer and the Ni electrode 9. Electrolytic plating is performed to deposit Ni13 in the voids. When the voids within a thickness range of about 100 μm from the base material were filled, the electricity was turned off, the sample was taken out, the insulating plate 7 and the conductive wire 8 were removed, and then ultrasonic cleaning was performed in distilled water to remove any residue remaining in the ceramic layer. Remove the electrolyte and dry. Next, the ceramic layer is immersed in a TEOS solution in a vacuum to allow the TEOS solution to sufficiently penetrate into the voids within the ceramic layer. After that, it was heated to 400°C in the air in an electric furnace, and TEOS was converted to 5% by hydrolysis reaction as shown in Figure 5.
Convert to iOt6. Since volumetric shrinkage occurs during firing, in order to completely fill the voids with 5 ift, the impregnation and firing process in vacuum is repeated.

The change in weight of the sample is measured every time firing is completed, and the firing is considered complete when there is almost no increase in weight. In this way, a ceramic sprayed coating was obtained in which the voids within the ceramic layer within the base material constraint range of 100 μm were filled with Ni, and the voids within the surface constraint range of 200 μm were filled with SiO□.

Next, the voids obtained by the above method were filled with Ni and Si.
Examples of ceramic sprayed coating filled with O□, ceramic sprayed coating without any filling treatment for comparison, ceramic sprayed coating where all the voids were filled with Ni, and ceramic sprayed coating where all the voids were filled with 5ift. The same thermal shock resistance test as in 1 was conducted. As a result, as shown in Table 1, it was confirmed that thermal shock resistance and adhesion to the base material were significantly improved in a ceramic sprayed coating in which the base material side of the ceramic layer was filled with Ni and the surface side was filled with 5iOz. .

(Margins below this page) In addition, a thermal cycle test was conducted in which heating to 1000°C in the air in an electric furnace and cooling to room temperature was repeated, and the results of evaluating thermal fatigue resistance and oxidation resistance are shown in Table 2. As shown, the base material side of the ceramic layer is Ni1, the surface side is SiO2, and A
In the ceramic sprayed coating filled with l2O3 and ZrO2, no cracks or peeling were observed, and no oxidation of the base material occurred, and it was confirmed that the thermal fatigue resistance and oxidation resistance were improved.

(Margin below this page) Example 4 As shown in Fig. 6, on the base material l of Ni-based alloy, the base material side was CoNlCrAIY alloy, and the surface side was ZrOz-6wt%.
Y2O3, with ZrO□-61vt% Y20. After forming the ceramic layer 5, it is immersed in a TEO3 solution in a vacuum to impregnate the voids within the ceramic layer with the TEO3 solution.

Thereafter, it is heated to 400° C. in the air in an electric furnace, and TEOS is converted to SiO□6 by a hydrolysis reaction. Volume shrinkage occurs during firing, so the voids are completely filled with SiO□6
In order to fill it with water, the process of impregnation and firing in vacuum is repeated. The change in weight of the sample is measured every time firing is completed, and filling is completed when no increase in weight is observed. In this way, all the voids in the ceramic layer are filled with SiO
A heat-resistant ceramic coated member having an intermediate layer filled with □ and whose composition changes continuously between the ceramic layer and the base material was obtained.

Next, a heat-resistant ceramic coated member having an intermediate layer whose composition changes continuously between the ceramic layer and the base material, in which the voids in the ceramic layer obtained by the above method are filled with SiO□, and Thermal shock resistance was evaluated in the same manner as in Example 1 for a heat-resistant ceramic coated member having an intermediate layer 4 in which the composition continuously changes between the two ceramic layers whose voids are not filled with SiO□ and the base material.

In the sample in which the crystallization voids were not filled with SiO□, cracks occurred in the center of the ceramic layer when the center surface temperature exceeded 800°C, but in the sample in which all the voids were filled with 5i02, the center surface temperature was 1000°C. It was confirmed that no cracks occurred in the ceramic layer P up to this point, and that the thermal shock resistance could be improved.

Example 5 As shown in FIG. 3, ZrO
After forming a 6 wt% Y2O3 film 5 to a thickness of 300 μm by plasma spraying, a conductive wire 8 is attached to the back surface of the copper base material 1 by soldering or the like, and the parts other than the surface of the ceramic layer 5 are covered with water-impermeable material such as silicone rubber. It is coated with a magnetic insulator 7. This is immersed in an aqueous solution containing copper ions, such as a copper sulfate electrolyte 10, and the electrolyte is sufficiently infiltrated into the voids in the ceramic layer 5 by vacuum impregnation or the like, and then a DC voltage 11 is applied between it and the copper electrode 9. Then, electrolytic plating is performed to deposit copper 12 in the voids as shown in FIG. At this time, the voltage was controlled so that the current density varied with the plating time as shown in FIG. As the current density increases,
Although the deposition rate increases, the circulation of the electrolyte within the fine pores is poor, making it impossible to supply copper ions in time. This progresses rapidly in large pores, and the filling rate of the pores decreases in the interlayer gold body. In this way,
A ceramic sprayed coating is obtained in which the voids in the ceramic layer are filled with copper as shown in Figure 8, and the copper filling rate changes in the thickness direction (the filling rate is significant on the base material side, and small on the surface side). Ta.

Then the void obtained by the above method is filled with copper,
In addition, thermal shock resistance was evaluated in the same manner as in Example 1 for a ceramic sprayed coating in which the copper filling rate changes in the thickness direction and for comparison, a ceramic sprayed coating that was not subjected to copper filling treatment.

As a result, it was confirmed that thermal shock resistance and adhesion to the base material were significantly improved in a ceramic sprayed coating in which the voids were filled with copper and the copper filling rate varied in the thickness direction.

Example 6 The entire surface of the part exposed to combustion gas of a Ni-based alloy gas turbine rotor blade A as shown in FIG. 9 (shaded area in FIG. 9)
Then, the voids according to the present invention were formed using SiO in the same manner as in Example 1.
A ceramic spray coating filled with □ was formed. Also,
The void according to the present invention was prepared using Ni and 5 in the same manner as in Example 3.
A ceramic spray coating filled with iOt was formed. The thickness of the ceramic layer is 300mm. czm, and the CoNlCrAIY alloy layer of the bonding layer is 100 μm.

Next, these gas turbine blades A and, for comparison, gas turbine blades with ceramic sprayed coatings that were not subjected to filling treatment were subjected to an atmospheric heating test using an electric furnace at 1050°C, and a heating test at 1050°C. A thermal cycle test was conducted in which air heating in an electric furnace and air cooling outside the furnace were repeated. In addition, in the heat cycle test, the heating time was 30 minutes, and the cooling temperature was 20 minutes.
The temperature was set at 0°Cl2O min. As a result, in the air heating test, it was found that the ceramic film of the present invention was formed with a ceramic film with the voids filled with Sin, and the wing with a ceramic film with the voids filled with Ni and 5102, even after about 1000 hours of testing. It was healthy. On the other hand, in the case of the blade on which the ceramic film was formed and which was not subjected to the filling treatment, the film peeled off after about 300 hours. In addition, as a result of thermal cycle tests, the air gap of the present invention was formed with a ceramic film filled with 5iOz, and the air gap was filled with Ni and SiO2,
In the blades on which the ceramic coatings filled with Al2O3 and ZrO2 were formed, the ceramic coatings remained sound even after being repeated too many times. On the other hand, in the blade on which the ceramic film was formed and which was not subjected to the filling treatment, the ceramic layer peeled off after about 100 repetitions. In this way, the turbine blade of the present invention having a ceramic film with the voids filled is less prone to damage such as peeling of the ceramic film compared to conventional ones, and is made of Ni-based alloy due to the heat shielding effect of the ceramic film. Since the base material temperature can be stably reduced, the reliability and life of the turbine blade can be improved. The ceramic coating according to the present invention can be applied not only to the turbine blades shown in this example, but also to equipment and members exposed to high heat loads, such as turbine combustors, rocket engine combustors, and nozzles.

〔Effect of the invention〕

Since the present invention is constructed as described above, it is possible to improve the thermal shock resistance, corrosion resistance, oxidation resistance, and adhesion of the ceramic sprayed coating to the substrate, thereby preventing cracking and peeling even at high temperatures. It is possible to provide an excellent heat-resistant ceramic heat-resistant coating member that is free of heat-resistant coatings. In addition, the heat-resistant ceramic coated member according to the present invention is promising as a material for moving and stationary blades and combustors of high-temperature gas turbines, which are expected to be developed in the future, and combustors of high-performance rocket engines, and has great potential to be of great benefit to industry. .

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of a ceramic-coated heat-resistant member obtained by thermal spraying, Fig. 2 is a cross-sectional schematic diagram of a ceramic-coated heat-resistant member in which all the voids are filled with 5 iOz, and Fig. 3 is a schematic cross-sectional view of a ceramic-coated heat-resistant member obtained by thermal spraying.
The figure is an explanatory diagram of a method for filling voids by electroplating, FIG. 4 is a schematic cross-sectional view of a ceramic-coated heat-resistant member in which a portion of the void is filled with Cu, and FIG. , FIG. 6 is a schematic cross-sectional view of a ceramic-coated heat-resistant member filled with SiO□, and FIG. 8 is a graph showing changes in plating time and current density, FIG. 8 is a cross-sectional view of a state where a specific gap is filled, and FIG. 9 is a perspective view of a turbine blade in which the present invention is implemented. DESCRIPTION OF SYMBOLS 1...Base material, 2...Thermal spray particles, 3...Void, 4...
... Bonding layer, 5... Ceramic layer, 6... SiO□ filled in the void, 12... Cu filled in the void
13... Ni filled in the void, 14... Intermediate layer whose composition changes continuously.

Claims (7)

[Claims] 1. A heat-resistant coated member having a ceramic sprayed coating having a laminated structure of molten particles on the surface of the heat-resistant member, wherein the sprayed coating is filled with a heat-resistant substance made of a metal or an alloy. 2. The filling material is SiO_2, Al_2O_3, ZrO_
2. The ceramic-coated heat-resistant member according to claim 1, wherein the ceramic-coated heat-resistant member is made of a ceramic of 2 or a mixture thereof. 3. 2. The ceramic-coated heat-resistant member according to claim 1, wherein the filling material is made of a metal such as Cu, Ni, or Co, or an alloy thereof. 4. The ceramic-coated heat-resistant member according to claim 1, 2 or 3, wherein the filling material or the filling rate of the voids varies in the thickness direction of the coating. 5. Claims 1, 2 and 3, wherein the base material is a heat-resistant alloy containing Fe, Co or Ni as a main component, or Cu or a Cu alloy.
or the ceramic-coated heat-resistant member described in 4. 6. 6. The ceramic-coated heat-resistant member according to claim 1, wherein the ceramic-coated void on the base material side is filled with a filler material made of a metal or an alloy, and the upper void is filled with a non-metallic material. 7. 7. The ceramic-coated heat-resistant member according to claim 6, wherein the nonmetallic substance is an oxide, nitride, boride, carbide, silicide, or a mixture thereof.