JP2017190263A - Sealer, sealer coating liquid, anticorrosive coat, high temperature member and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealer that can seal a pore of an anticorrosive coat over the long term, the anticorrosive coat to protect a high temperature member such as a gas turbine or a heat transfer pipe at a thermal power generation from a corrosive and oxidative combustion gas atmosphere such as oxygen, sulfur oxide, or hydrogen sulfide, and also does not corrode a base material.SOLUTION: The present invention provides a sealer that seals a pore of an anticorrosive coat and comprises a glass having the composition in which the content of PbO is 5-50 mass% and the total content of ZnO and BOis 25-60 mass%.SELECTED DRAWING: Figure 1

Description

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

  In thermal power generation, coal, oil, and LNG are burned in a boiler, and the turbine is rotated using the high-temperature and high-pressure gas, or the turbine is rotated by steam generated using the heat of the high-temperature gas. Is going. For this reason, high temperature members, such as a gas turbine and a heat exchanger tube, are exposed to corrosive and oxidizing combustion gas atmospheres, such as oxygen, sulfur oxide, and hydrogen sulfide of 500-1000 degreeC. As a result, there is a problem of a decrease in life due to so-called high temperature corrosion.

  Since the high temperature member deteriorates due to the corrosion caused by the acid gas, it is necessary to frequently replace the high temperature member. Since replacement of the high temperature member increases the power generation cost, a high temperature member that does not deteriorate for a longer period of time is required.

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

JP 2001-152307 A Japanese Unexamined Patent Publication No. 60-194063

For example, Patent Document 1 discloses a composite coating in which cermet or ceramics is formed by thermal spraying as a base layer, a sealing process is performed on the surface of the base layer with an oxide ceramic, and a glassy coating is further formed. The composite coating described in Patent Document 1 has no through pores and exhibits not only excellent corrosion resistance against corrosive gas, but also the service life of the substrate is remarkably improved. Examples of sealing agents include heat-resistant organic resin ceramic suspensions, chromic acid that generates Cr ₂ O ₃ by heating, inorganic metal compound solutions and colloidal solutions that generate metal oxides by firing, metal alkoxide alcohol solutions Metal chloride aqueous solution or alcohol solution, metal phosphate aqueous solution, metal hydroxide colloid solution, alcohol or water suspension containing metal oxide ultrafine powder, or a mixture of two or more of these are recommended . However, these sealing agents have a problem that gas is generated even after solidification and complete sealing cannot be performed. Moreover, although the use of Na ₂ SiO ₃ , NaPO ₃ , NaHSiO ₃ as an inorganic binder has been proposed, these include alkali metals. As described in Patent Document 2, since alkali metals cause high-temperature corrosion, if the above-described inorganic binder is used, these may corrode a base material or a coating film.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the sealing agent which can seal the pore of a corrosion-resistant film over a long period of time, and does not corrode a base material.

The sealing agent of the present invention is a sealing agent for sealing pores of a corrosion-resistant film, and is made of glass containing PbO 5 to 50% and ZnO + B ₂ O ₃ 25 to 60% by mass percentage. And Here, “ZnO + B ₂ O ₃ ” means the total content of ZnO and B ₂ O ₃ .

The sealing agent having the above-mentioned configuration is made of glass containing PbO that significantly lowers the softening point and ZnO or B ₂ O ₃ that has a lower effect of lowering the softening point than PbO at an appropriate ratio. Thereby, the pores of the corrosion-resistant film can be easily sealed, and the situation in which the viscosity of the glass is too low to react with the film or drop off from the surface of the film can be prevented.

In the sealing agent of the present invention, the glass has a glass composition of PbO 5-50%, ZnO + B ₂ O ₃ 25-60%, ZnO 0-40%, B ₂ O ₃ 0-40%, MgO + CaO + SrO + BaO as a glass composition. _{0~40%, Li 2 O + Na} 2 O + K 2 O 0~20%, SiO 2 0~40%, preferably contains _Al 2 O 3 _0~30%. 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.

  If the said structure is employ | adopted, it will become easy to produce the glass which has a suitable viscosity characteristic.

  The sealant coating solution of the present invention is characterized by containing the above-described sealant.

  If the said structure is employ | adopted, it will become easy to apply | coat a sealing agent on a corrosion-resistant film by simple methods, such as brush coating.

The corrosion-resistant film of the present invention is a corrosion-resistant film containing 50% by mass or more of one or more selected from ZrO ₂ , Al ₂ O _3, and SiO _2, and the powder composed of the above-described sealing agent is attached to the surface. It is characterized by that. “Adhering to the surface” includes not only the state where the sealant powder is chemically and physically bonded to the corrosion-resistant coating, but also the state where the sealant powder is geometrically caught by the corrosion-resistant coating and does not fall off. .

  The high-temperature member employing the corrosion-resistant coating having the above-described configuration can seal the pores of the corrosion-resistant coating using a high-temperature atmosphere at the time of use, so that the preliminary firing step can be omitted.

Further, the corrosion-resistant film of the present invention is a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and a part or all of pores present on the surface are in percentage by mass. It is characterized by being filled with a sealing agent made of glass containing 5 to 50% of PbO and 25 to 60% of ZnO + B ₂ O ₃ .

  The high-temperature member employing the corrosion-resistant coating having the above-mentioned configuration is because the sealing agent is fixed in the pores of the corrosion-resistant coating, so that the sealing agent layer may fall off during installation during installation or use, The situation where it breaks can be avoided effectively.

The method for producing a corrosion-resistant film of the present invention is characterized in that the above-described sealing agent coating solution is applied onto a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _2. And

  In the manufacturing method of the corrosion-resistant film of this invention, it is preferable to have the process of baking after application | coating of a sealing agent coating liquid.

The high-temperature member of the present invention has a corrosion-resistant coating containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _{2 on} the surface of the base material, and the powder comprising the above-described sealing agent is It has adhered to the surface of the said corrosion-resistant film.

The high-temperature member of the present invention has a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _{2 on} the surface of the base material, and pores existing on the surface of the corrosion-resistant film. Part or all of is filled with a sealing agent made of glass containing 5 to 50% PbO and 25 to 60% ZnO + B ₂ O ₃ by mass percentage.

The method for producing a high-temperature member of the present invention includes the steps of forming a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ on the base material, and the above-described method on the corrosion-resistant film. And a step of applying a sealant coating solution. In addition, it is preferable to dry a sealing agent coating liquid after sealing agent application | coating.

  In the manufacturing method of the high temperature member of this invention, it is preferable to have the process of baking after application | coating of a sealing agent coating liquid. In addition, "baking after application | coating of a sealing agent coating liquid" includes the case where baking is carried out after drying a sealing agent coating liquid.

Sample No. 3 is a photograph showing the results of SEM observation and EDS analysis at × 2000 of the corrosion resistant coating of No. 3. Sample No. 3 is a photograph showing the result of SEM observation at × 500 of No. 3 corrosion-resistant film. Sample No. 5 is a photograph showing the result of SEM observation at × 500 of the corrosion-resistant film of No. 5.

  Hereinafter, embodiments of the present invention will be described.

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

  In the glass constituting the sealant, the proportion of PbO in the glass composition is 5 to 50% by mass. PbO is a component that contributes to glass formation as an intermediate oxide, and is a component that lowers the viscosity of the glass to lower the temperature at which it softens and flows. If the content of PbO is too large, the temperature at which it softens and flows becomes too low, and there is a risk that it will be washed away from the surface of the corrosion-resistant coating. Therefore, the content of PbO contained in the glass composition is 5 to 50% by mass percentage, preferably 7 to 48%, 10 to 44%, and particularly preferably 18 to 42%.

Glass constituting the sealing agent, the ratio of the total amount of ZnO and _B 2 _{O 3} accounts for the glass composition is 25 to 60 mass%. ZnO and B ₂ O ₃ are components for lowering the viscosity of the glass to lower the temperature at which it softens and flows, but the effect of lowering the temperature at which it softens and flows is smaller than that of PbO. For this reason, it becomes possible to optimize the temperature at which the glass softens and flows by containing appropriate amounts of these components together with PbO. The content of ZnO + B ₂ O ₃ contained in the glass composition is 25 to 60% by mass percentage, preferably 28 to 55%, 30 to 52%, particularly preferably 30 to 47%. If the content of ZnO + B ₂ O ₃ is too large, the softening flow temperature becomes high, and there is a possibility that it cannot be sufficiently sealed. On the other hand, if it is too small, the softening flow temperature is too low, There is a possibility that the sealing agent reacts with the coating or falls off from the coating surface.

Glass constituting the sealing agent, for example, as a glass composition, PbO 5 to _50% in percent by _{mass, ZnO + B 2 O 3 25~60} %, 0~40% ZnO, B 2 O 3 0~40%, MgO + CaO + SrO + BaO 0~ _{40%, Li 2 O + Na} 2 O + K 2 O 0~20%, SiO 2 0~40%, may be used those containing _Al 2 O 3 _0~30%. The reason for limiting the glass composition as described above will be described below. In the following description, “%” means mass%.

The contents of PbO and ZnO + B ₂ O ₃ are as described above, and a description thereof is omitted here.

  ZnO is also a component contributing to glass formation as an intermediate oxide. Moreover, it is a component for lowering | hanging the viscosity of glass and making the temperature which softens and flows low. If the content of ZnO is too large, devitrification is likely to occur, and if the content is too small, the melting temperature becomes high and it becomes difficult to melt, or the glass becomes unstable. The content of ZnO is preferably 0 to 40%, 0.5 to 35%, 5 to 30%, particularly preferably 10 to 25%.

B ₂ O ₃ is a glass network-forming oxide. Moreover, it is a component for lowering | hanging the viscosity of glass and making the temperature which softens and flows low. B handling in the ₂ O ₃ of the content is too great water resistance is lowered normal humidity is difficult. B ₂ When the content of O ₃ is too small glass tends to be devitrified and becomes unstable. The content of B ₂ O ₃ is preferably 0 to 40%, 0.5 to 35%, 5 to 30%, particularly preferably 10 to 25%.

  The content of MgO + CaO + SrO + BaO is preferably 0 to 80%, particularly preferably 0 to 25%. When there is too much MgO + CaO + SrO + BaO, it will become easy to devitrify.

  MgO is a component that lowers the melting temperature of glass. When there is too much content of MgO, it will become easy to devitrify. The content of MgO is preferably 0 to 40%, 0 to 25%, particularly preferably 0 to 10%.

  CaO is a component that lowers the melting temperature of glass. When there is too much content of CaO, it will become easy to devitrify. The CaO content is preferably 0 to 40%, 0 to 30%, particularly preferably 0 to 20%.

  SrO is a component that lowers the melting temperature of glass. When there is too much content of SrO, it will become easy to devitrify. The SrO content is preferably 0 to 40%, 0 to 30%, particularly preferably 0 to 20%.

  BaO is a component that lowers the melting temperature of glass. When there is too much content of BaO, it will become easy to devitrify, and when there is too little content, a melting temperature will become high and it will become difficult to fuse | melt. The BaO content is preferably 0 to 50%, 0 to 40%, 0 to 30%, particularly preferably 1 to 25%.

Li ₂ O, Na ₂ O, and K ₂ O are components for lowering the viscosity of the glass to lower the temperature at which it softens and flows, but cause high-temperature corrosion. The content of Li ₂ O + Na ₂ O + K ₂ O is preferably 0 to 20%, 0 to 15%, 0.1 to 13%, particularly preferably 1 to 12%. The content of Li ₂ O is preferably 0 to 20%, 0 to 15%, 0 to 13%, particularly preferably 0.1 to 12%. The content of Na ₂ O is preferably 0 to 20%, 0 to 15%, 0.01 to 13%, particularly preferably 0.1 to 12%. The content of K ₂ O is preferably 0 to 20%, 0.01 to 10%, particularly preferably 0.1 to 12%.

SiO ₂ is a network-forming oxide of glass, and is a component that contributes to glass formation and simultaneously increases water resistance. If the content of SiO ₂ is too large, devitrification tends to occur, and if the content is too small, the water resistance becomes low and the glass becomes unstable. The content of SiO ₂ is preferably 0 to 50%, 0.5 to 40%, particularly preferably 1 to 35%.

Al ₂ O ₃ is a component that increases water resistance and increases the viscosity of the glass. When the content of Al ₂ O ₃ is too large, devitrification tends to occur, and when the content is too small, the water resistance becomes low and handling at normal humidity becomes difficult. The content of Al ₂ O ₃ is preferably 0 to 30%, 0.1 to 20%, particularly preferably 0.5 to 10%.

In addition to the above components, P ₂ O ₅ , TiO ₂ , MnO ₂ , Fe ₂ O ₃ , CoO, NiO, CuO, Y ₂ O ₃ , ZrO ₂ , SnO ₂ , and La ₂ are within a range that does not impair the desired characteristics. O ₃ , CeO ₂ , Bi ₂ O _{3 and the} like may be included up to 10% each.

  The glass constituting the sealant is preferably a glass powder having an average particle size of 10 nm to 500 μm, particularly 1 to 100 μm. Here, the “average particle size” is defined by D50 calculated on the basis of the number of particles when the particle size of an arbitrary powder is measured by the laser diffraction scattering method.

  The sealant coating liquid of the present invention refers to a paste or slurry obtained by mixing a sealant with an inorganic solvent such as various resins, paints, organic solvents, sol-gel liquids, water glass, and water. By making it into a paste or slurry, it becomes easy to apply uniformly on the corrosion-resistant coating. Resins, paints, and sol-gel solutions have a function of fixing the sealing agent on the coating until the sealing agent is softened and does not fall off from the corrosion-resistant coating. Examples of such resins and paints, sol-gel solutions, and water glasses include vinyl resins such as unsaturated polyester resins, epoxy resins, polyvinyl butyral, polyvinyl alcohol, polybutyl methacrylate, polymethyl methacrylate, and polyethyl methacrylate. Cellulose resins such as acrylic resins, ethyl cellulose, nitrocellulose, amide resins, silicone resins, polytitanocarboxyl silane solutions, metal alkoxides such as tetraethoxysilane and partial condensate solutions thereof, sodium silicate as defined in JIS K1408 No. 1, No. 2, No. 3, etc. can be used.

  Further, boric acid powder or boron oxide powder may be added to the sealant coating solution in order to promote the permeability when the sealant is in a molten state and penetrates into the corrosion-resistant coating.

The corrosion-resistant film of the present invention is a corrosion-resistant film 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 against corrosive and oxidizing combustion gas atmospheres of oxygen, sulfur oxides, hydrogen sulfide and the like at 500 to 1000 ° C., for example.

Examples of the corrosion resistant coating include a corrosion resistant coating having stabilized ZrO ₂ as a main constituent (hereinafter referred to as a stabilized ZrO ₂ -based corrosion resistant coating). Stabilized ZrO ₂ is mainly composed of ZrO ₂ , and one or more kinds of stable 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. An agent is added. Specifically, the ZrO ₂ content is 85% by mass or more, preferably 85 to 95% by mass, and the stabilizer content is 15% by mass or less, preferably 5 to 15% by mass. If the ZrO ₂ content is 85% by mass or more, the corrosion resistance of the coating can be ensured, and the phase from the tetragonal or cubic to monoclinic phase of ZrO ₂ generated near 1000 ° C. in the cooling process after plasma spraying. Metastasis can also be suppressed. Incidentally the content of ZrO ₂ is less than 85 wt%, the corrosion resistance of the coating is reduced.

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

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 film is too small, it is difficult to suppress permeation of acidic gas. On the other hand, when the film thickness of the corrosion-resistant film is too large, the thermal stress generated by the thermal cycle increases, and the corrosion-resistant film 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 preferably has the above-mentioned corrosion-resistant film formed thereon. In addition, as a material of a high temperature member main body (base material), the metal material which has at least one of Fe, Ni, Co, and Cr as a main component is preferable. The corrosion-resistant coating is preferably formed directly on the substrate, but for the purpose of improving adhesion and the like, one or more underlayers may be provided between the substrate and the corrosion-resistant coating.

For example, when the above-described stabilized ZrO ₂ -based corrosion-resistant film is formed on a substrate made of SUS, a layer made of, for example, an M—Cr—Al—Y alloy (M = Ni, Co, Fe) is used as the underlayer. It is preferable to provide it. The M-Cr-Al-Y alloy is an alloy mainly composed of Ni or Co having excellent high-temperature oxidation resistance and high-temperature corrosion resistance, and added with Cr, Al, and Y. 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 permeation of acid gas, the lower the porosity of the underlayer, the more advantageous.

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

  The high-temperature member is preferably a thermal power generation turbine or heat transfer tube that generates power by collecting kinetic energy or thermal energy via a fluid such as steam or air. However, it is not limited to these. For example, it can be suitably applied to various engines.

Next, the manufacturing method of the high temperature member using the sealing agent of the present invention is a stabilized ZrO ₂ -based corrosion-resistant coating film on a base material made of SUS with an underlayer made of an M-Cr-Al-Y alloy. An example of forming the case will be described. In the following description, if a metal tube is used as the substrate, a heat transfer tube with a corrosion-resistant coating can be produced. The production 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, an underlayer made of an M—Cr—Al—Y 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 becomes easy to obtain a base layer having good adhesion to SUS as a base material and low porosity. Moreover, it is preferable to use the powder which consists of a M-Cr-Al-Y type alloy for the thermal spraying powder used in this case. The M-Cr-Al-Y 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 preferably 10 to 45 μm. When the particle size of the thermal spray powder is large, the porosity of the base layer formed by gas spraying is increased. In addition, if the particle size of the thermal spray powder is small, clogging of the jet port (port) for supplying the thermal spray powder to gas or plasma is likely to occur, and it takes time to form the thermal spray coating of any film thickness, resulting in thermal spraying. Cost is likely to increase.

Next, a stabilized ZrO ₂ -based corrosion resistant coating is formed on the underlayer made of the M—Cr—Al—Y 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 an atmospheric pressure plasma spraying method and a vacuum plasma spraying method can be used. It is preferable to use stabilized ZrO ₂ powder as the thermal spraying powder used at this time. The corrosion resistant coating can be formed by a spraying technique other than plasma spraying (for example, gas spraying), a cold spray, an aerosol deposition method, or the like.

The average particle size of the stabilized ZrO ₂ powder is preferably 10 to 75 μm, 10 to 53 μm, particularly preferably 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 increased. In addition, if the average particle size of the stabilized ZrO ₂ powder is small, clogging of the spray port (port) for supplying the sprayed powder to the plasma is likely to occur, and it takes time to form a sprayed coating having an arbitrary film thickness. The thermal spraying cost tends to be high.

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

  For forming the sealing agent layer, for example, a paste or slurry containing the sealing agent described above is applied onto the corrosion-resistant coating by a method such as brushing or spraying, and further dried as necessary. In this way, a sealant layer can be formed. It should be noted that other methods may be employed as long as the sealing agent powder does not fall off the corrosion-resistant coating, such as sputtering and thermal spraying.

  The sealant layer of the high temperature member thus produced is in a state where the sealant powder is adhered to the surface of the corrosion-resistant coating, and is not yet in a state of completely closing the pores, Can be installed. That is, when the use is started, it is exposed to a high temperature atmosphere, and the heat causes the sealing agent to soften and flow to fill 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 sealant layer is dried (and before actual use). As firing conditions, for example, 10 to 2 hours at 300 to 1000 ° C. is preferable. By firing in advance before actual use, it is possible to prevent the sealant layer from falling off or being damaged during transfer or installation at the place of use.

Hereinafter, based on an Example, this invention is demonstrated in detail.
[Preparation of sealant]
Table 1 shows examples of the present invention (sample Nos. 1 to 4).

The sealant sample was prepared as follows. First, a glass batch prepared to have the composition in the table was melted at 1000 ° C. for 1 hour. Next, after forming this into a film, it was pulverized and classified to obtain a sealing agent (sealing agent samples No. 1 to 4) made of glass powder having an average particle diameter of 50 μm.
[Production of high-temperature components]
The high temperature member was produced as follows. First, the SUS310S base material is degreased, washed, and blasted, and an alloy powder having an average particle diameter of 10 to 45 μm made of a Co—Ni—Cr—Al—Y alloy is sprayed at high speed to provide high temperature oxidation resistance and resistance. An underlayer (Co—Ni—Cr—Al—Y alloy layer) excellent in high temperature corrosion resistance was formed. The thickness of the underlayer was uniform and was 200 to 400 μm. The film thickness of the underlayer was measured with a micrometer. The film thickness can be adjusted by first moving the thermal spraying device parallel to the substrate and spraying it, and measuring with a micrometer how much film thickness can be obtained with a single spray. This was done by adjusting the number of times.

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

  Subsequently, a sealant layer was formed on the corrosion-resistant film by the following method. First, polyvinyl butyral resin, thinner, and sealant sample No. Any one of 1-4 was mixed and the sealing agent paste was produced. Next, a sealant paste was applied onto the corrosion-resistant film by brushing and then baked at 550 ° C. for 4 days. Thus, the high temperature member (high temperature member sample No. 1-4) by which the corrosion-resistant film was sealed with the sealing agent was obtained.

  Further, the anticorrosion film was not sealed with a sealant, and the other steps were performed using a high temperature member sample No. 1 to 4, the high temperature member sample No. 5 was prepared and used as a comparison target.

  About the obtained high temperature member sample No. 1-4, the permeability to the film of a sealing agent was evaluated. The results are shown in Table 1. The results of SEM and EDS are shown in FIGS. 1 and 2 are high-temperature member sample Nos. 3 is a result of observation and analysis of No. 3, and FIG. 5 shows the observation and analysis results.

  In addition, the permeability to the coating was obtained by embedding the cut sample in a resin and polishing the cut surface, and then performing SEM (scanning electron microscope) observation and EDS (energy dispersive X-ray analysis) analysis on the cut surface. . When the element contained in the sealant was detected in the corrosion-resistant film, the permeability was evaluated as “◯”, and when the element was not detected as “X”.

  As a result, the high temperature member sample No. 5, it can be seen from FIG. 3 that a large number of pores exist in the corrosion-resistant film. On the other hand, high temperature member sample No. which is an embodiment of the present invention. As is clear from Table 1, in Nos. 1 to 4, the sealing agent penetrated into the corrosion-resistant coating. Moreover, it can be seen from FIG. 1 that the sealing agent penetrates into the corrosion-resistant film, and FIG. 2 that only a small number of pores are present in the corrosion-resistant film. In addition, since the pore which exists in a corrosion-resistant film is thought not to communicate with the outside, it is considered that there is no practical problem.

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

  The corrosion-resistant coating using the sealant of the present invention is a protective film for a thermal power generation turbine or heat transfer tube that recovers kinetic energy or thermal energy from a high-temperature combustion gas via a fluid such as steam or air. It is preferable to use it. Specifically, it is suitable as a protective film for turbines and heat transfer tubes of 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, the present invention is not limited to these, and is also suitable as a protective film for various engines. The high-temperature member of the present invention is suitable as a turbine or heat transfer tube for various types of engines such as gas turbine power generation, coal-fired power generation, coal gasification combined power generation, oil-fired power generation, waste power generation, and geothermal power generation.

DESCRIPTION OF SYMBOLS 1 Sealing agent 2 Corrosion-resistant film 3 Underlayer 4 Resin

Claims (11)

A sealing agent for sealing pores of a corrosion-resistant film, comprising a glass containing PbO 5 to 50% and ZnO + B ₂ O ₃ 25 to 60% by mass percentage. Glass has a glass composition of PbO 5-50% by mass, ZnO + B ₂ O ₃ 25-60%, ZnO 0-40%, B ₂ O ₃ 0-40%, MgO + CaO + SrO + BaO 0-40%, Li ₂ O + Na _{2. O + K 2 O 0~20%,} SiO 2 0~40%, sealing agent according to claim 1, characterized in that it contains _Al 2 O 3 _0~30%.   A sealing agent coating liquid comprising the sealing agent according to claim 1. It is a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _2, and the powder comprising the sealing agent according to claim 1 or 2 is attached to the surface. Corrosion-resistant coating characterized by A corrosion-resistant film 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 PbO 5 to 50% by mass percentage, ZnO + B A corrosion-resistant film characterized by being filled with a sealant made of glass containing ₂ O ₃ 25 to 60%. 4. Production of a corrosion-resistant coating film characterized by applying the sealing agent coating liquid according to claim 3 on a corrosion-resistant coating film containing 50% by mass or more of at least one 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 sealant coating solution. The powder comprising the sealing agent according to claim 1 or 2, wherein the surface of the base material has a corrosion-resistant coating containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO _2. A high-temperature member characterized by adhering to the surface of a corrosion-resistant film. The surface of the substrate 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 part or all of the pores present on the surface of the corrosion-resistant coating are in mass A high-temperature member characterized by being filled with a sealing agent made of glass containing 5 to 50% PbO and 25 to 60% ZnO + B ₂ O _{3 by} percentage. The step of forming a corrosion-resistant film containing 50% by mass or more of at least one selected from ZrO ₂ , Al ₂ O ₃ and SiO ₂ on a substrate, and the sealant coating solution according to claim 3 on the corrosion-resistant film A method for producing a high-temperature member. The method for producing a high-temperature member according to claim 10, further comprising a step of baking after applying the sealant coating solution.