JP2020063161A - Sealing agent, coating solution for sealing agent, corrosion resistant coating, high temperature member, and methods for producing the same - Google Patents

Abstract

To provide a sealing agent that can seal the pores of a corrosion-resistant coating and does not corrode the substrate for a long period of time.SOLUTION: Provided is a sealing agent for sealing pores of a corrosion resistant coating, characterized by comprising a glass that contains, in mole %, BiOby 10 to 50%, ZnO by 10 to 50%, BOby 0 to 25%, SiOby 0 to 40%, AlOby 0 to 30%, MgO+CaO+SrO+BaO by 0 to 40%, and LiO+NaO+KO by 0 to 20%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing agent for filling the pores of a corrosion-resistant coating, a corrosion-resistant coating and a high temperature member produced using the same.

  In thermal power generation, coal, oil, and LNG are burned in a boiler, and the high-temperature and high-pressure gas is used to rotate the turbine, or the steam generated using the heat of the high-temperature gas is used to rotate the turbine to generate power. Is going. Therefore, high temperature members such as a gas turbine and a heat transfer tube are exposed to a corrosive and oxidizing combustion gas atmosphere of oxygen, sulfur oxides, hydrogen sulfide and the like at 500 to 1000 ° C. As a result, there is a problem of shortening the life due to so-called high temperature corrosion.

  Corrosion due to such acidic gas causes deterioration of the high temperature member, and therefore it is necessary to frequently replace the high temperature member. Since replacement of the high temperature member increases the power generation cost, there is a demand for a high temperature member that does not deteriorate further.

  Therefore, it has been studied to form a corrosion resistant coating on the surface of these high temperature members to prevent deterioration. In order to extend the life of the high temperature member by the corrosion resistant coating, how to form a dense coating without pores is important. That is, if pores are present in the corrosion-resistant coating, the acid gas reaches the base material of the high temperature member through the pores and corrodes the high temperature member.

JP 2001-152307 A

For example, Patent Document 1 discloses a composite film in which a cermet or ceramics is formed as a base layer by thermal spraying, the surface of the base layer is sealed with an oxide ceramic, and a glassy film is formed. The composite coating described in Patent Document 1 has no through pores, exhibits not only excellent corrosion resistance to corrosive gases, but also has a markedly improved service life of the base material. As the pore-sealing agent, a heat-resistant organic resin ceramics suspension, chromic acid that produces Cr ₂ O ₃ by heating, a solution and colloidal solution of an inorganic metal compound that produces a metal oxide by firing, a metal alkoxide alcohol solution , Metal chloride aqueous solution or alcohol solution, metal phosphate aqueous solution, metal hydroxide colloidal solution, alcohol or water suspension containing ultrafine powder of metal oxide, or a mixture of two or more thereof is recommended. There is. However, these sealing agents have a problem in that gas is generated even after solidification and a complete sealing cannot be achieved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sealing agent capable of sealing the pores of a corrosion-resistant coating and not corroding the substrate for a long period of time.

The pore-sealing agent of the present invention is a pore-sealing agent for sealing the pores of a corrosion-resistant coating, and in mol%, Bi ₂ O _{3 is} 10 to 50%, ZnO is 10 to 50%, and B ₂ O _{30 is} 0 to 50%. _{25%, SiO 2 0~40%,} Al 2 O 3 0~30%, MgO + CaO + SrO + BaO 0~40%, characterized in that it consists of glass containing 2 O 0~20% Li 2 O + Na 2 O + K. Here, “MgO + CaO + SrO + BaO” means the total content of MgO, CaO, SrO, and BaO. “Li ₂ O + Na ₂ O + K ₂ O” means the total content of Li ₂ O, Na ₂ O and K ₂ O.

The sealing agent having the above-mentioned structure includes Bi ₂ O ₃ which significantly lowers the softening point and ZnO, B ₂ O ₃ , MgO, CaO, SrO and BaO which have a smaller softening point lowering effect than Bi ₂ O _3. It is made of glass having a low content of B ₂ O ₃ of 25 mol% or less which easily reacts with corrosive and oxidative gases and shortens the life of the pore-sealing agent, even though it is contained in an appropriate proportion. This makes it possible to easily seal the pores of the corrosion-resistant coating, prevent the glass from reacting with the coating due to too low a viscosity, and preventing the glass from falling off the coating surface. Hold for a period.

In sealer of the present invention, glass is a glass composition including, _Bi 2 _O 3 _10~50% by _{mole%, 10~50% ZnO, B 2} O 3 0~25%, SiO 2 0~40%, _{al 2 O 3 0~30%, MgO} + CaO + SrO + BaO 0~40%, Li 2 O + Na 2 O + K 2 O 0~20%, ZnO + B 2 O 3 10~70%, Bi 2 O 3 -B 2 O 3 0~40%, It is preferable to contain Fe ₂ O ₃ 0 to 10%. Here, “ZnO + B ₂ O ₃ ” means the total content of ZnO and B ₂ O ₃ . And _"Bi 2 _O 3 _-B 2 _{O 3"} means a value obtained by subtracting the content of _Bi 2 _{O 3 B} 2 _{O 3} from content.

  If the above configuration is adopted, it becomes easy to manufacture a glass having a long life and appropriate viscosity characteristics.

  The sealing agent coating liquid of the present invention is characterized by containing the above-mentioned sealing agent.

  If the above configuration is adopted, it becomes easy to apply the pore-sealing agent onto the corrosion-resistant coating by a simple method such as brush coating.

The corrosion-resistant coating of the present invention is a corrosion-resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and the powder made of the above-mentioned sealing agent is attached to the surface. It is characterized by "Adhering to the surface" includes not only the state where the sealing agent powder is chemically and physically bonded to the corrosion-resistant coating, but also the state where the sealing agent powder is geometrically caught by the corrosion-resistant coating and does not fall off. .

  In the high temperature member employing the corrosion resistant coating having the above structure, the pores of the corrosion resistant coating can be sealed by using the high temperature atmosphere at the time of use, so that the preliminary firing step can be omitted.

The corrosion-resistant coating of the present invention is a corrosion-resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and some or all of the pores present on the surface are It is characterized by being filled with the sealing agent.

  The high-temperature member adopting the corrosion-resistant coating having the above-mentioned configuration, the sealing agent is fixed in the pores of the corrosion-resistant coating, so that the sealing agent layer may fall off during the transfer or the installation at the place of use, You can effectively avoid the situation of damage.

The method for producing a corrosion-resistant coating of the present invention is characterized by applying the above-mentioned sealing agent coating liquid onto a corrosion-resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2. And

  The method for producing a corrosion-resistant coating of the present invention preferably has a step of baking after applying the sealing agent coating liquid.

The high temperature member of the present invention has, on the surface of the base material, a corrosion resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and the powder containing the above-mentioned sealing agent is It is characterized in that it is attached to the surface of the corrosion resistant coating.

The high-temperature member of the present invention has a corrosion-resistant coating film containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _{2 on} the surface of the base material, and is present on the surface of the corrosion-resistant coating film. A part or all of the pores are filled with the above-mentioned sealing agent.

The method for manufacturing a high-temperature member of the present invention includes the steps of forming a corrosion-resistant coating film containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ on a base material, and performing the above-mentioned processing on the corrosion-resistant coating film. And a step of applying a sealing agent coating liquid. It is preferable to dry the coating liquid for the sealing agent after the coating of the sealing agent.

  The method for producing a high-temperature member of the present invention preferably has a step of baking after applying the sealing agent coating liquid. In addition, "baking after applying the sealing agent coating liquid" includes the case where the sealing agent coating liquid is dried and then baked.

Sample No. It is a photograph which shows the result of SEM observation and EDS analysis in x2000 of 10 corrosion-resistant coatings. Sample No. It is a photograph which shows the result of SEM observation of the corrosion-resistant film of 10 at x500. Sample No. It is a photograph which shows the result of SEM observation of 18 corrosion resistant coatings at x500.

  Hereinafter, embodiments of the present invention will be described.

The pore-sealing agent of the present invention seals pores existing in the corrosion-resistant coating. The corrosion resistant coating to which the sealing agent of the present invention can be applied is not particularly limited, and for example, it can be used as a sealing agent for a corrosion resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ .

The glass constituting the pore-sealing agent is, in mol%, Bi ₂ O ₃ 10 to 50%, ZnO 10 to 50%, B ₂ O ₃ 0 to 25%, SiO ₂ 0 to 40%, Al ₂ O ₃ 0 to 0%. _{30%, MgO + CaO + SrO} + BaO 0~40%, Li 2 O + Na 2 O + K 2 containing O 0 to 20%. The reason for limiting the glass composition as described above will be described below. In the following description, "%" means mol%.

Bi ₂ O ₃ is a component that contributes to glass formation as a modified oxide or an intermediate oxide, and is a component that lowers the viscosity of the glass and lowers the softening flow temperature. If the content of Bi ₂ O ₃ is too large, the softening and flowing temperature may be too low, and the Bi ₂ O ₃ may be washed away from the surface of the corrosion resistant coating. On the other hand, if the amount is too small, the softening and flowing temperature becomes high, and there is a possibility that sufficient sealing cannot be achieved. The content of Bi ₂ O ₃ is 10 to 50%, preferably 15 to 45%, 20 to 41%, and particularly preferably 26 to 38%.

  ZnO is a component that contributes to glass formation as an intermediate oxide. It is also a component for lowering the viscosity of the glass and lowering the softening and flowing temperature. If the content of ZnO is too large, devitrification is likely to occur, and softening and flow will be difficult. On the other hand, if the amount is too small, vitrification becomes difficult. The ZnO content is 10 to 50%, preferably 14 to 45%, 18 to 40%, and particularly preferably 21 to 35%.

B ₂ O ₃ is a glass network forming oxide. Further, it is a component for lowering the temperature of softening and flowing by lowering the viscosity of glass, but it is a component that easily reacts with corrosive and oxidizing gases and shortens the life of the sealing agent. If the content of B ₂ O ₃ is too large, the life of the sealing agent tends to be shortened. In addition, the water resistance becomes low, and handling at normal humidity becomes difficult. The content of B ₂ O ₃ is 0 to 25%, preferably 1 to 23%, 3 to 22%, and particularly preferably 10 to 19%.

As described above, ZnO and B ₂ O ₃ are components for lowering the viscosity of glass and lowering the softening flow temperature, but the effect of lowering the softening flow temperature is smaller than that of Bi ₂ O ₃ . Therefore, by containing an appropriate amount of these components together with Bi ₂ O ₃ , it becomes possible to optimize the softening and flowing temperature of the glass. If the amount of ZnO + B ₂ O ₃ is too much, the softening and flowing temperature may be too low, and the pore-sealing agent may react with the coating film or may drop from the coating surface. On the other hand, if the amount is too small, the softening and flowing temperature becomes high, and there is a possibility that sufficient sealing cannot be achieved. ZnO ₊ B 2 _{O 3} is 10% to 70%, 12-60%, 14-50%, particularly preferably 15% to 45%.

Bi ₂ O ₃ -B ₂ O ₃ is 0-40%, 1-37%, 3-35%, particularly preferably 5-27%. If Bi ₂ O ₃ -B ₂ O ₃ is too large difficult to vitrify. Further, the softening and flowing temperature may be too low, and the pore-sealing agent may react with the coating or may fall off the coating surface.

SiO ₂ is a glass network-forming oxide, and is a component that contributes to glass formation and at the same time enhances water resistance. If the content of SiO ₂ is too large, devitrification tends to occur. The content of SiO ₂ is 0 to 40%, preferably 9 to 30%, and particularly preferably 14 to 22%.

Al ₂ O ₃ is a component that enhances water resistance and viscosity of glass. If the content of Al ₂ O ₃ is too large, devitrification is likely to occur, and softening and flow will be difficult. The content of Al ₂ O ₃ is 0 to 30%, preferably 0.5 to 20%, particularly preferably 1 to 10%.

  MgO + CaO + SrO + BaO is 0 to 40%, preferably 1 to 30%, 2 to 20%, and particularly preferably 3 to 10%. If the amount of MgO + CaO + SrO + BaO is too large, devitrification is likely to occur, and softening and fluidization are difficult.

  MgO is a component that lowers the melting temperature of glass. If the content of MgO is too large, devitrification is likely to occur, and softening and flow will be difficult. The content of MgO is preferably 0 to 40%, 0 to 30%, and particularly preferably 0 to 20%.

  CaO is a component that lowers the melting temperature of glass. If the content of CaO is too large, devitrification is likely to occur, and softening and flow will be difficult. The content of CaO is preferably 0 to 40%, 0 to 30%, and particularly preferably 0 to 20%.

  SrO is a component that lowers the melting temperature of glass. If the content of SrO is too large, devitrification is likely to occur, and softening and flow will be difficult. The SrO content is preferably 0 to 40%, 0 to 30%, and particularly preferably 0 to 20%.

  BaO is a component that has a large effect of lowering the melting temperature of glass. When the content of BaO is too large, devitrification is likely to occur, and softening and flow becomes difficult. The content of BaO is preferably 0 to 40%, 1 to 30%, and particularly 2 to 20%.

Li ₂ O, Na ₂ O, and K ₂ O are components for lowering the viscosity of glass and lowering the temperature at which it softens and flows, but it causes high-temperature corrosion. Li ₂ O + Na ₂ O + K ₂ O is 0 to 20%, preferably 0 to 15%, 0.1 to 10%, and particularly preferably 1 to 5%. The content of Li ₂ O is preferably 0 to 20%, 0 to 15%, 0 to 10%, and particularly preferably 0.1 to 5%. The content of Na ₂ O is preferably 0 to 20%, 0 to 15%, 0.01 to 10%, and particularly preferably 0.1 to 5%. The content of K ₂ O is preferably 0 to 20%, 0.01 to 10%, and particularly preferably 0.1 to 5%.

  The glass may contain the following components in addition to the above components.

Fe ₂ O ₃ is a component that stabilizes the glass and suppresses devitrification. On the contrary, when the content of Fe ₂ O ₃ is too large, devitrification is likely to occur. The content of Fe ₂ O ₃ is preferably 0 to 10%, 0.1 to 5%, and particularly 0.3 to ₃ %.

Within a range not to impair the desired _{properties, P 2 O 5, TiO 2} , MnO 2, CoO, NiO, CuO, Y 2 O 3, ZrO 2, SnO 2, La 2 O 3, CeO 2 or the like up to 10%, respectively It may be contained.

  PbO is a component that contributes to glass formation as an intermediate oxide and a component that lowers the viscosity of glass and lowers the temperature at which it softens and flows, but it is mentioned as a substance having a high environmental load. Therefore, it is particularly preferable that the content of PbO is less than 10%, less than 1%, and substantially not contained. Here, "substantially free of" means that PbO is not intentionally added to the glass, and does not mean that even unavoidable impurities are completely removed. More objectively, it means that the content of these components including impurities is less than 0.1%.

  The glass constituting the pore-sealing agent is preferably a glass powder having an average particle diameter of 0.1 to 500 μm, particularly 1 to 100 μm. Here, the “average particle size” is defined as D50 calculated on the volume basis of particles when the particle size of an arbitrary powder is measured by a laser diffraction scattering method.

  The sealing agent coating liquid of the present invention refers to a paste or slurry prepared by mixing the sealing agent with various resins, paints, organic solvents, sol-gel solutions, water glass, water and other inorganic solvents. By making it into a paste or a slurry, it becomes easy to uniformly apply the pore-sealing agent onto the corrosion-resistant coating. In addition, the resin, the paint, and the sol-gel liquid have a function of fixing the pore-sealing agent on the coating until the pore-sealing agent softens and does not fall off the corrosion-resistant coating. Examples of such resins and paints, sol-gel liquids, and water glass include unsaturated polyester resins, epoxy resins, polyvinyl butyral, vinyl resins such as polyvinyl alcohol, polybutyl methacrylate, polymethyl methacrylate, polyethyl methacrylate, and the like. Acrylic resins, cellulose resins such as ethyl cellulose and nitrocellulose, amide resins, silicone resins, polytitanocarboxyl silane solutions, solutions of metal alkoxides such as tetraethoxysilane and partial condensates thereof, sodium silicate specified in JIS K1408. No. 1, No. 2, No. 3, etc. can be used.

  In addition, a small amount of boric acid powder or boron oxide powder may be added to the sealing agent coating liquid in order to promote the permeability when the sealing agent becomes in a molten state and penetrates into the corrosion resistant coating.

The corrosion-resistant coating of the present invention is a corrosion-resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ . This type of corrosion-resistant coating can have corrosion resistance to a corrosive or oxidizing combustion gas atmosphere of oxygen, sulfur oxides, hydrogen sulfide, etc. at 500 to 1000 ° C., for example.

Examples of the corrosion resistant coating include a corrosion resistant coating containing stabilized ZrO ₂ as a main constituent (hereinafter referred to as a stabilized ZrO ₂ -based corrosion resistant coating). Stabilized ZrO ₂ contains ZrO ₂ as a main component and is one or more kinds of stable materials selected from Y ₂ O ₃ , MgO, CaO, SiO ₂ , CeO ₂ , Yb ₂ O ₃ , Dy ₂ O ₃ , HfO _{2 and the} like. The agent is added. Specifically, it means that the content of ZrO ₂ is 85% by mass or more, preferably 85 to 95% by mass, and the content of the stabilizer is 15% by mass or less, preferably 5 to 15% by mass. When the content of ZrO ₂ is 85% by mass or more, the corrosion resistance of the coating can be ensured, and the phase of tetragonal or cubic to monoclinic ZrO ₂ which occurs at around 1000 ° C. in the cooling process after plasma spraying. Metastasis can also be suppressed. If the content of ZrO ₂ is less than 85% by mass, the corrosion resistance of the coating will be reduced.

  The porosity of the corrosion resistant coating is preferably 5% or less, more preferably 4% or less. By making the corrosion-resistant coating dense, it is possible to further prevent the corrosion of the base material caused by the permeation of the acidic gas through the coating. If the porosity of the corrosion-resistant coating is too high, it becomes difficult to completely seal the pores with the pore-sealing agent, and it becomes difficult to suppress the permeation of the acid gas. Here, "porosity of 5% or less" means that the ratio of the total area of surface cracks and voids to the area of the observation screen is 5% when the cross section of the corrosion resistant coating is observed with a scanning electron microscope at a magnification of 1000 times. It means that

The thickness of the corrosion resistant coating is preferably 10 to 1000 μm, 10 to 500 μm, 50 to 400 μm, and particularly preferably 70 to 300 μm. If the thickness of the corrosion-resistant coating is too small, it will be difficult to suppress the permeation of acidic gas. On the other hand, if the thickness of the corrosion-resistant coating is too large, the thermal stress generated by the thermal cycle increases, and the corrosion-resistant coating easily peels off. The porosity of the corrosion-resistant coating can be adjusted by changing the particle size of the sprayed powder (stabilized ZrO ₂ powder or inorganic glass powder).

  The high temperature member of the present invention is formed with the above-mentioned corrosion resistant coating. The material of the high temperature member body (base material) is preferably a metal material containing at least one of Fe, Ni, Co and Cr as a main component. The corrosion-resistant coating is preferably formed directly on the substrate, but one or more underlayers may be provided between the substrate and the corrosion-resistant coating for the purpose of improving adhesion and the like.

For example, when the above-mentioned stabilized ZrO ₂ -based corrosion resistant coating is formed on a base material made of SUS, as an underlayer, for example, an M-Cr-Al-Y-based alloy (M = Ni, Co, Fe at least one kind) is used. It is preferable to provide a layer consisting of The M-Cr-Al-Y-based alloy is an alloy containing Ni, Co, or the like as a main component, which has excellent high temperature oxidation resistance and high temperature corrosion resistance, and Cr, Al, and Y added thereto. This type of alloy is characterized in that it easily adheres to both SUS and the stabilized ZrO ₂ -based corrosion resistant coating.

  The porosity of the underlayer is preferably 1% or less. From the viewpoint of suppressing the permeation of acidic gas, the lower the porosity of the underlayer, the more advantageous.

  The thickness of the underlayer is preferably 10 to 500 μm, particularly 50 to 400 μm, and further preferably 70 to 350 μm. From the viewpoint of suppressing the permeation of acid gas, the thicker the underlayer, the more advantageous. Further, the underlayer generally has an effect of relaxing the thermal stress caused by the difference in the thermal expansion characteristics generated at the interface between the base material and the corrosion resistant film, but if the film thickness of the underlayer is too small, it is difficult to obtain the effect of relaxing the thermal stress. Become. On the other hand, if the film thickness of the underlayer is too large, the thermal stress generated by the thermal cycle inside the power generation facility becomes large, and the underlayer easily peels off. The porosity of the underlayer can be adjusted by changing the particle size of the sprayed M-Cr-Al-Y alloy powder or the like.

  The high temperature member is preferably a turbine or a heat transfer tube for thermal power generation that recovers kinetic energy and thermal energy via a fluid such as steam or air to generate power. However, it is not limited to these. For example, it is suitable for various engines.

Next, a method for producing a high temperature member using the sealing agent according to the present invention will be described in which a stabilized ZrO ₂ system corrosion resistant coating is formed on a substrate made of SUS via an underlayer made of an M—Cr—Al—Y system alloy. An example will be described in which the case is formed. In the following description, if a metal tube is used as the base material, a heat transfer tube with a corrosion resistant coating can be manufactured. The manufacturing method of the present invention is not limited to the following description. Of course, it goes without saying that the formation of the underlayer is not an essential requirement.

  First, a base layer made of an M-Cr-Al-Y-based alloy is formed on a base material made of SUS.

  The formation of the underlayer is not particularly limited, but is preferably formed by gas spraying such as high speed flame spraying (HVOF). By using high-speed flame spraying, it is easy to obtain an underlayer having good adhesion to SUS which is a base material and low porosity. Further, as the thermal spraying powder used at this time, it is preferable to use a powder made of an M-Cr-Al-Y-based alloy. The M-Cr-Al-Y-based alloy is as described above, and the description thereof is omitted here. The average particle size of the sprayed powder is preferably 10 to 75 μm, 10 to 53 μm, and particularly 10 to 45 μm. When the particle size of the sprayed powder is large, the porosity of the underlayer formed by gas spraying becomes high. If the particle size of the sprayed powder is small, the jet port (port) for supplying the sprayed powder to gas or plasma is likely to be clogged, and it takes time to form a sprayed coating having an arbitrary thickness, resulting in spraying. The cost tends to be high.

Next, a stabilized ZrO ₂ based corrosion resistant coating is formed on the underlayer made of the M—Cr—Al—Y based alloy.

The stabilized ZrO ₂ -based corrosion resistant coating can be formed by a plasma spraying method. As the plasma spraying method, various methods such as atmospheric pressure plasma spraying method and vacuum plasma spraying method can be used. As the thermal spraying powder used at this time, it is preferable to use stabilized ZrO ₂ powder. The corrosion resistant coating may be formed by a spraying technique other than plasma spraying (for example, gas spraying), cold spraying, aerosol deposition, or the like.

The stabilized ZrO ₂ powder preferably has an average particle size of 10 to 75 μm, 10 to 53 μm, and particularly 10 to 45 μm. When the average particle size of the stabilized ZrO ₂ powder is large, the porosity of the corrosion resistant coating formed by plasma spraying is high. Further, when the average particle diameter of the stabilized ZrO ₂ powder is small, the jet port (port) for supplying the sprayed powder to the plasma is likely to be clogged, and it takes time to form a sprayed coating of an arbitrary thickness, resulting in Moreover, the spraying cost is likely to be high.

Subsequently, a sealing agent layer is formed on the stabilized ZrO ₂ -based corrosion resistant coating.

  The sealing agent layer is formed, for example, by applying a paste or a slurry (sealing agent coating solution) containing the above-mentioned sealing agent on the corrosion-resistant coating by a method such as brush coating or spraying, and further drying if necessary. In this way, the sealing agent layer can be formed. In addition, as the pore-sealing agent, one containing two or more kinds of glass powders whose composition and mixing ratio are adjusted so as to have the above-mentioned composition as a whole may be used. The sealing agent can be formed by any other method such as sputtering or thermal spraying as long as the sealing agent powder does not fall off from the corrosion-resistant coating.

  The sealing agent layer of the high-temperature member thus produced is in a state in which the sealing agent powder is adhered to the surface of the corrosion-resistant coating and is not yet in a state of completely closing the pores. It can be installed in. That is, when the use is started, it is exposed to a high temperature atmosphere, and the heat softens and flows the sealing agent to fill the pores existing on the surface of the corrosion resistant coating.

  In producing the high temperature member of the present invention, firing may be performed after the sealing agent layer is dried (and before actual use). The firing conditions are preferably, for example, 300 to 1000 ° C. and 10 minutes to 10 hours. By pre-baking before actual use, it is possible to prevent the sealing agent layer from falling off or being damaged during transportation or installation at a use place.

  Hereinafter, the present invention will be described in detail based on examples.

[Preparation of sealing agent]
Tables 1 and 2 show examples (Sample Nos. 1 to 17) of the present invention.

  The sealing agent samples of the examples were prepared as follows. First, glass batches prepared to have the compositions shown in Tables 1 and 2 were melted at 1000 to 1200 ° C. for 1 hour. Next, this was molded into a film, crushed and classified to obtain a sealing agent sample made of glass powder having an average particle diameter of 50 μm.

  The softening point was measured using a differential thermal analyzer according to the method described in "For those who make glass for the first time" by Masayuki Yamane.

[Fabrication of high temperature member]
The high temperature member was manufactured as follows. First, after degreasing and cleaning the SUS310S base material, blasting treatment is performed, and alloy powder of Co-Ni-Cr-Al-Y-based alloy having an average particle diameter of 10 to 45 μm is subjected to high-speed flame spraying for high-temperature oxidation resistance and resistance. An underlayer (Co-Ni-Cr-Al-Y alloy layer) excellent in high temperature corrosiveness was formed. The film thickness of the underlayer was 50 to 200 μm. The thickness of the underlayer was measured with a micrometer. To adjust the film thickness, first move the thermal spraying device in parallel with the base material to perform thermal spraying, measure with a micrometer how much film thickness can be obtained by one thermal spraying, and based on this, perform thermal spraying. It was performed by adjusting the number of times.

Next, 8 mass% Y ₂ O ₃ -92 mass% ZrO ₂ powder having an average particle diameter of 10 to 45 μm was plasma sprayed onto the underlayer at atmospheric pressure to form a corrosion resistant coating. The thickness of the corrosion resistant coating was uniform and was 50 to 200 μm. The adjustment and measurement of the film thickness of the corrosion resistant coating were carried out in the same manner as in the thermal spraying of Co-Ni-Cr-Al-Y alloy.

  Subsequently, a sealing agent layer was formed on the corrosion resistant coating by the following method. First, a polyvinyl butyral resin, a thinner, and a sealing agent sample were mixed to prepare a sealing agent paste. Next, a sealing agent paste was applied onto the corrosion resistant coating by brushing, and then baked at 600 to 750 ° C. for 1 hour. In this way, high temperature members (high temperature member samples No. 1 to 17) in which the corrosion resistant coating was sealed with the sealing agent were obtained.

  In addition, the corrosion-resistant coating was not sealed with a sealing agent, and the other steps were performed in the high temperature member sample No. High temperature member sample No. 18 was produced and used as a comparison target.

  The obtained high temperature member sample No. For 1 to 17, the penetrability of the sealing agent into the coating film was evaluated. The results are shown in Tables 1 and 2. The results of SEM (scanning electron microscope) and EDS (energy dispersive X-ray analysis) are shown in FIGS. 1 and 2 are high-temperature member sample Nos. 10 is the result of observation and analysis, and FIG. 18 observation results. In the figure, 1 is a sealing agent, 2 is a corrosion resistant coating, 3 is a base layer, and 4 is a resin.

  For the permeability to the coating, the cut sample was embedded in the resin 4, the cut surface was polished, and then the cut surface was observed by SEM and EDS analysis. When the element contained in the sealing agent 1 was detected in the corrosion resistant coating 2, the permeability was evaluated as ◯, and when not detected, it was evaluated as x.

  As a result, the high temperature member sample No. having no sealing agent layer was formed. As for No. 18, it can be seen from FIG. 3 that many pores are present in the corrosion resistant coating. On the other hand, the high temperature member sample No. which is an example of the present invention. 1 to 17, as is clear from Tables 1 and 2, the sealing agent 1 penetrated into the corrosion-resistant coating 2. Further, it can be seen from FIG. 1 that the pore-sealing agent 1 has penetrated into the corrosion-resistant coating 2 and from FIG. 2 that only a small number of pores are present in the corrosion-resistant coating 2. Sample No. In No. 10, it is considered that there is no problem in practical use because the pores existing in the corrosion resistant coating 2 do not communicate with the outside.

  These facts show that the sealing agent of the present invention has a high sealing property.

  Corrosion-resistant coating using the sealing agent of the present invention, as a protective film of a turbine or heat transfer tube of thermal power generation that recovers kinetic energy and thermal energy from a high temperature combustion gas through a fluid such as steam or air to generate electricity. It is preferable to use. Specifically, it is suitable as a protective film for turbines and heat transfer tubes for gas turbine power generation, coal thermal power generation, coal gasification combined power generation, oil thermal power generation, waste power generation, geothermal power generation, and the like. However, it is not limited to these, and is suitable as a protective film for various engines. Further, the high-temperature member of the present invention is suitable as a turbine or heat transfer tube for gas turbine power generation, coal-fired power generation, coal gasification combined-cycle power generation, oil-fired power generation, waste power generation, geothermal power generation, various engines, or the like.

1 Sealing agent 2 Corrosion resistant coating 3 Underlayer 4 Resin

Claims (11)

A sealing agent for sealing the pores of a corrosion-resistant coating, which is, in mol%, Bi ₂ O ₃ 10 to 50%, ZnO 10 to 50%, B ₂ O ₃ 0 to 25%, SiO ₂ 0 to 40. %, Al ₂ O ₃ 0-30%, MgO + CaO + SrO + BaO 0-40%, Li ₂ O + Na ₂ O + K ₂ O 0-20%. The composition of the glass is mol% of Bi ₂ O ₃ 10 to 50%, ZnO 10 to 50%, B ₂ O _{3 to} 25%, SiO ₂ 0 to 40%, Al ₂ O ₃ 0 to 30%, MgO + CaO + SrO + BaO. _{0~40%, Li 2 O + Na} 2 O + K 2 O 0~20%, ZnO + B 2 O 3 10~70%, Bi 2 O 3 -B 2 O 3 0~40%, contains _Fe 2 O 3 _0~10% The sealing agent according to claim 1, wherein   A sealing agent coating liquid comprising the sealing agent according to claim 1 or 2. It is a corrosion resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and the powder comprising the sealing agent according to claim 1 or 2 adheres to the surface. Corrosion resistant coating. A corrosion resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ , wherein some or all of the pores present on the surface are the sealing holes according to claim 1 or 2. A corrosion resistant coating characterized by being filled with a chemical. 4. Production of a corrosion-resistant coating film, which comprises applying the sealing agent coating liquid according to claim 3 on a corrosion-resistant coating film containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2. Method.   The method for producing a corrosion-resistant coating film according to claim 6, further comprising a step of baking after applying the sealing agent coating liquid. The powder comprising the sealing agent according to claim 1 or 2 has a corrosion-resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _{2 on} the surface of the base material. A high temperature member characterized by being attached to the surface of a corrosion resistant coating. The surface of the base material has a corrosion resistant coating containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and some or all of the pores present on the surface of the corrosion resistant coating are claimed. A high-temperature member filled with the sealing agent according to Item 1 or 2. The step of forming a corrosion-resistant coating film containing 50% by mass or more of one or more kinds selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ on a substrate, and the sealing agent coating liquid according to claim 3 on the corrosion-resistant coating film. And a step of coating the high temperature member.   The method for manufacturing a high-temperature member according to claim 10, further comprising a step of baking the sealing agent coating liquid after coating.