JPH0874068A - Refractory coating structure - Google Patents

Abstract

PURPOSE: To obtain a refractory-coated structure resistant to corrosive gases and corrosion of fused salt by coating a glass film fused to the surface of a member with a refractory film contg. inorg. binder, fusion or solid-phase welding the coating film. CONSTITUTION: A glass film is fused to the surface of a metallic base material itself or, as required, on the surface of a member formed by thermally spraying a metal resistant to heat and corrosion on the base material. Cr2 O3 or its multiple oxide is heated and incorporated into the glass film when being fused, and a vitreous ceramic thin film is deposited as a vitreous film. The glass film or vitreous glass film is then coated with a refractory film formed by binding an aggregate of ceramic, etc., with an inorg. binder such as metal alkoxide, and further a glass film or a vitreous ceramic thin film is fused or solid-phase welded to the refractory film. Consequently, a refractory-coated structure impermeable to corrosive gases such as gaseous chlorine and highly resistant to the corrosion of the molten metal, glass and salt is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is impermeable to corrosive gases such as chlorine gas, hydrogen chloride gas, and sulfurous acid gas, and has high corrosion resistance to molten metal, molten glass, and molten salt. It relates to a refractory coating structure.

[0002]

2. Description of the Related Art Members used in high temperature corrosive atmospheres such as incinerators are severely corroded by chlorine gas, hydrogen chloride gas, sulfurous acid gas and the like. Further, the ash generated by the combustion is melted to generate a molten salt, which is deposited on the surface of the member and corrodes the surface. Two characteristics, that is, the corrosion resistance to corrosive gas and the corrosion resistance to molten salt, are required at the same time for the internal members of a refuse incinerator and the like. Traditionally, these problems have been addressed by using high grade steels such as Inconel alloys or by spraying special alloys. However, the conventional method is expensive and not sufficient in performance.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to combine two characteristics of corrosion resistance against corrosive gas and molten salt and molten glass. It is intended to provide a refractory coating structure having a new structure.

[0004]

The above problems can be solved by the following means. That is, 1. A glass film is fused to the surface of a member, and a refractory film bonded with an inorganic binder is coated on the glass film, and the glass film is fused or solid-phase bonded to the refractory film. A refractory coating structure characterized by: 2. Heat-resistant surface, a member having a structure in which a corrosion-resistant metal is sprayed, a glass film is fused on the sprayed layer, a refractory film bonded with an inorganic binder is coated on the glass film, A refractory film structure, wherein the glass film is fused or solid-phase bonded to the refractory film. 3. Refractory coating structure of the glass bonding layer is described in 1 or 2, characterized in that it comprises a mixed oxide of Cr 2 _O 3 or Cr ₂ O _3, were generated heated during glass fusion. 4. A glassy ceramic thin film is applied to the surface of the member,
A refractory coating structure, comprising a refractory coating bonded by an inorganic binder on the thin film in a solid phase. 5. A glass ceramic thin film is deposited on the thermally sprayed layer of a member having a structure in which heat and corrosion resistance are sprayed on the surface, and a refractory film bonded by an inorganic binder is solid-phase bonded on the thin film. A refractory coating structure characterized by comprising: 6. Refractory coating structure according to 4 or 5, characterized in that it comprises the inorganic binder is a solid phase bond upon heating generated Cr 2 _{O 3,} or mixed oxide of Cr ₂ O _3.

[0005]

Since the molten component of ash is deposited on the surface of the in-furnace member such as an incinerator, the member surface is required to have corrosion resistance against molten salt. For molten salt, a refractory coating made of zirconia, alumina, nitride, carbide or other ceramic as an aggregate exhibits excellent corrosion resistance, but the refractory coating has pores originally and 100% penetration of corrosive gas. I can't shut it off.
While the vitreous coating is the most effective protective coating against high temperature corrosive gases, it focuses on being attacked by molten salt,
The present invention compensates the defects of a glass film by first coating a glassy film on the surface of the member and then laminating a film of a refractory material on the glassy film, thereby making the metal of the member from both molten salt and corrosive gas. It protects parts. By laminating a vitreous film under the refractory film which originally has pores, the surface portion is provided with corrosion resistance against molten salt, and the lower layer is provided with a function of preventing corrosive gas from permeating.
Since one coating cannot have both functions, this problem was solved by laminating a glassy film and a refractory coating on the surface of the member. In order to make this structure possible, it is necessary that the vitreous film and the member are solid-phase bonded or fusion-bonded, and the glassy film and the refractory are fusion-bonded or solid-phase bonded.

Here, the glassy coating means both a glass coating and a glassy ceramic coating. The glassy ceramic coating means a coating formed by coating a solution of a metal alkoxide, an inorganic metal polymer, etc., drying and heating, and is used in a thin film thickness of 0.1 to several microns. Since it is an extremely thin film, there is an advantage that it can be coated without considering the coefficient of thermal expansion of the base material to be coated. In the present invention, this glassy coating layer may be a so-called glass coating single layer or a glassy ceramic coating single layer, or may be a glass coating further laminated with a glassy ceramic coating. Here, regarding the bonding form of the member and the vitreous coating, the glass layer is covered by fusion bonding to the member, and the vitreous ceramic is covered by solid-phase bonding to the member.

As a binder for the refractory film to be coated on the glassy film, an acidic binder such as phosphate, an alkaline binder such as silicate, a metal alkoxide, an inorganic metal polymer or the like is usually used. Any of the inorganic binders mentioned can be used, but in addition to these binders, water-soluble chromium compounds can also be used. The water-soluble chromium compound produces Cr ₂ O ₃ or Cr ₂ O ₃ double oxide by heating, or the mixture of the water-soluble chromium compound and the phosphate gives phosphorus compound oxide and Cr by heating.
₂ O ₃ is generated, or a double oxide of phosphorus oxide and Cr ₂
It produces a mixed oxide of O ₃ and has a low temperature (300 to 500 ° C.).
The refractory coating has the property of being firmly solid-phase bonded to the glassy coating even when heated to a certain degree, which is most advantageous for the purpose of the present invention.

As the source of Cr ₂ O ₃ or Cr ₂ O ₃ complex oxide, chromic acid, chromate, dichromate, chromium salt and soluble complex chromium compound are used as a solvent such as water. It can be used for some time. For example, CrO ₃
ZnO of the aqueous solution, an aqueous solution of CrO _3, MgO, CaO
CrCl ₂ , Cr ₂ (SO
₄ ) It can be used in the form of an aqueous solution such as ₃ . Among these,
ZnO, Mg0 in an aqueous solution of the aqueous solution CrO ₃ of CrO _3,
Aqueous solutions of oxides such as CaO give the most favorable results. Particularly, a solution obtained by adding ZnO or CaO to an aqueous solution of CrO ₃ or a mixture obtained by mixing ZnO and CaO is preferable. The addition ratio may be appropriately added from a very small amount to a saturated state. The above-mentioned solvents are most preferably water, and may be dissolved separately, but may be dissolved together in the same solvent. When a soluble chromium compound is mixed with an acidic binder such as phosphate, the adhesion to glass is remarkably improved only by adding a trace amount of the chromium compound to the acidic binder. 5 wt. The effect appears when the addition is about%.

For the purpose of the present invention, as the binder, in addition to the above-mentioned chromium compounds, metal alkoxides and polymers of inorganic group are particularly effective. As the metal alkoxide, any substance can be used as long as it produces an oxide of the metal element by heating. For example, Si, A
When a metal alkoxide solution such as L or Zr is mixed with oxide powders such as silica, alumina, zirconia, and chromia, carbides such as silicon carbide and silicon nitride, and nitride powders, and the like is coated on the glass film and heated. , A coating is formed on glass in the form in which these ceramic powders are bonded with an oxide ceramic produced from a metal alkoxide. Like the metal alkoxide, the inorganic metal polymer also produces an oxide of the metal element by heating, but a nitride is also produced depending on the heating atmosphere. Either oxide or nitride may be used for the purposes of the present invention. Typical polymers are polysilazane, borosiloxane, and the like, and oxides and nitrides of horisilazane are generated by a heating atmosphere. The most preferable binder for the refractory coating formed on the glassy coating (glass coating, glassy ceramic coating) of the present invention is to form Cr ₂ O ₃ or Cr ₂ O ₃ double oxide by heating. A binder containing a soluble chromium compound, that is, a binder in which a part or all is a soluble chromium compound, a metal alkoxide, and an inorganic metal polymer. As a binder containing a soluble chromium compound, a soluble chromium compound and an acidic binder (phosphate etc.)
Most preferred is a mixture of With these binders,
After heating, Cr ₂ O ₃ or a double oxide of Cr ₂ O ₃ and an oxide such as aluminum phosphate are formed in the binder.

The member which is the base material of the coating can be appropriately selected from a metal material itself or a structure obtained by subjecting a base metal to surface treatment of corrosion resistance and oxidation resistance. As the surface treatment for corrosion resistance and oxidation resistance, usual surface treatments such as thermal spraying, plating, heat treatment for diffusion and penetration of metals such as Cr and AL, and aluminizing can be appropriately selected. In the present invention, since the base material is heated to at least the glass fusion temperature, these surface treatments are effective when the base material does not have sufficient oxidation resistance. Thermal spraying is particularly effective as the surface treatment, but when a material subjected to thermal spray treatment is used as the substrate, it is difficult to completely fuse the glass film to the sprayed surface. There are innumerable pores in the sprayed film,
When the glass melts, the air trapped in the pores is difficult to completely escape. In addition, there is a drawback that the coating becomes thick due to the large unevenness and the large surface area. There is also a problem in the wettability of the molten glass with respect to the sprayed film. As a result, air bubbles remain in the coating, which induces film peeling or pinholes, and it has conventionally been a difficult problem to glass-coat the sprayed coating.

The present inventor adds a component which forms Cr ₂ O ₃ or a double oxide of Cr ₂ O ₃ during glass fusion to the glass coating to form a thin and bubble-free continuous coating. I was found to be done. Cr ₂ O ₃ or C
The component that forms the r ₂ O ₃ double oxide is most preferably a soluble chromium compound. That is, the above Cr ₂ O ₃ or C
Chromic acid, chromate salts, dichromate salts, chromium salts, and soluble complex chromium compounds used as a source of r ₂ O ₃ complex oxides are used after being dissolved in a solvent such as water. For example, an aqueous solution of CrO _3, ZnO in an aqueous solution of CrO _3, MgO, in dissolved form oxides such as _{CaO, CrCL 2, Cr 2 (SO} 4) can be used in the form of an aqueous solution of _3, and the like. Among these, an aqueous solution of CrO ₃ , C
An aqueous solution obtained by dissolving an oxide such as ZnO, MgO or CaO in an aqueous solution of rO ₃ gives the most preferable result. Particularly, a solution obtained by adding ZnO or CaO to an aqueous solution of CrO ₃ or a mixture obtained by mixing ZnO and CaO is preferable. The addition ratio may be appropriately added from a trace amount to a saturated state, but most preferable is ZnO per 1 mol of CrO _3.
Is added from 0.2 mol to the solubility limit, or ZnO and CaO are mixed and added from 0.2 mol to the solubility limit. By the addition of the soluble chromium compound as described above, the glass gets wet along the uneven surface of the sprayed film,
It forms an extremely thin continuous film. This is effective even when added in a small amount (about 1% to glass). It is presumed that since the film has good wettability and can form a thin film, a continuous film having no defects and no defect remains in the film. The glass layer does not need to be thick enough to completely fill the uneven surface of the thermal spray. In the present invention, even if part of the valleys of the irregularities is buried and some protrusions of the peaks remain, these protrusions are also wet with glass and coated with a thin continuous coating, so that they have sufficient corrosion resistance. From the viewpoint of thermal fatigue and thermal stress, this coating is preferable. Although there is no particular restriction on the composition of the sprayed alloy, the purpose of the sprayed coating of the present invention is to prevent oxidation at the time of melting the glass.
An alloy containing an oxidation resistant element typified by r, Si, Y or the like is preferable. An alloy containing Fe, Ni, Co bases and one or more of oxidation resistant elements such as AL, Cr, Si and Y as an essential component is preferable. The glass component of the present invention has extremely good wettability with respect to the thermal spray alloy containing these elements, and forms a continuous film of a glass film that is dense and has good adhesion.

In order to form a glass film, powders prepared by melting the target components or powders of each component are mixed and mixed with a binder solution, and a slurry or paste is applied to a substrate. To heat. The components of the glass used can be appropriately selected from various components according to the intended use,
However, it is preferable to adjust the thermal expansion coefficient to be the same as or slightly smaller than the thermal expansion coefficient of the base material to be fused during use. If the surface of the present glass film is coated with a thin film of glassy ceramic using the above-mentioned metal alkoxide and inorganic metal polymer solution, a more gas-tight film can be obtained.

The glassy coating of the present invention has sufficient resistance to high temperature corrosive gas, and the refractory coating on the surface has sufficient corrosion resistance to molten salt, molten glass and molten metal. Therefore, a corrosive gas (corrosion gas such as HCL, CL ₂ ) depends on the molten ash, and particularly useful for a boiler tube in a refuse incinerator in which molten salt corrosion occurs due to accumulated ash.

Refractory materials usable in the present invention are alumina,
Ordinary oxides such as zirconia, silica, magnesia, calcia, chromia, titania, etc., or one or more of these complex oxides, nitrides, carbides, fluorides such as calcium fluoride, glass powder, or heat resistance , Corrosion resistant metal powder, etc. can be appropriately selected and mixed and used. These aggregates are used in the form of powder, in the form of fibers, or in the form of particles, and the expansion coefficient is adjusted to be equal to or slightly smaller than that of the glass film. Incidentally, the above refractory,
When the glass is mixed with the binder solution, an inorganic binder other than the above-mentioned binders usually used for this type of application, for example, various sols (for example, alumina sol), colloidal silica and other commonly used binders. It goes without saying that the inorganic binder component can be appropriately added and used.

[0015]

The present invention will be described with reference to examples. Example 1 Substrate: The surface of φ20 × 100 mm mild steel was shot-blasted to roughen it, and then alloy powder of the following components (wt.%) Was sprayed to a thickness of 0.3 mm. C: 0.15 Si: 2.0 Mn: 1.0 Ni: 0.5 Cr: 27.0 Mo: 3.0 AL: 7.0 Fe: Bal. <Glass coating> A paste made by mixing a glass frit powder having a linear expansion coefficient of 10.5 × 10 ⁻⁶ and an appropriate firing temperature of 850 to 900 ° C. with a binder having the following composition so that the base can be seen on the sprayed film. It was applied thinly. <Binder composition> A solution in which ZnO was dissolved to a saturated state in a chromic acid solution prepared by adding 5 parts by weight of CrO _{3 to} 4 parts by weight of water. <Composition of paste> A mixture of 1.5 parts by weight of glass powder and 1.0 part by weight of the binder. After drying at room temperature, the temperature was raised to 900 ° C. over 5 hours, and the temperature was kept at 900 ° C. for 30 minutes to cool the furnace. The uneven surface of the thermal spray was coated with a thin brown glass film, and the valleys were partially filled with glass. The thickness of the glass film was a few microns to 30 microns. <Refractory coating> CaO-stabilized zirconia ceramic powder (under 45 microns) is used for the aggregate. The binder used had the following composition. A mixture of 1 part by weight of an aqueous solution of zinc chromate having the following composition with 3 parts by weight of a 50% aqueous solution of aluminum (I) phosphate. Composition of zinc chromate 1 part by weight of ZnO was added to a chromic acid solution prepared by adding 5 parts by weight of CrO _{3 to} 4 parts by weight of water. The mixing ratio of the aggregate and the binder was 3.2 parts by weight of the aggregate and 1.1 parts by weight of the binder, and the mixture was mixed to form a paste and applied on the glass surface. After being dried at room temperature and kept at 100 ° C. for 1 hour, the temperature was raised to 550 ° C. over 4 hours and kept at 550 ° C. for 3 hours to cool the furnace. It was covered with a tightly adherent coating of zirconia ceramic. The adhesion strength did not come off in the tape peeling test. On the other hand, a zirconia ceramic powder mixed with a 50% aqueous solution of aluminum (I) phosphate in the form of a paste was applied and heat-treated under the same conditions, and 20% of the coating area was peeled by a tape peeling test. <Evaluation Test> A resin was applied to both end faces of the sample coated with zirconia and masked, and an exposure test was performed in a humidified saturated HCL gas stream atmosphere at room temperature. Three
After being left for a month, no rust was generated and no change in weight was observed. The same test was performed on the thermal spray only sample described above for comparison. In this case, the surface turned dark green, and after washing with water, a reduction in the film thickness of the sprayed film was also recognized, and part of the coating film was shaved off by hand.

Example 2 <Substrate> φ20 × 50 mm SUS430 (18% Cr steel) <Glass coating> After polishing the surface of the substrate with a sander to roughen it, silica powder, clay, hydrated borax, sodium nitrite , Magnesium carbonate, bentonite, water mixed to obtain a linear expansion coefficient of 11
It was immersed in a frit slurry adjusted to × 10 ⁻⁶ to cover the frit, dried at room temperature, and dried at 100 ° C. for 1 hour.
Then, after putting it in electricity kept at 850 ° C. and holding it for 10 minutes, it was immediately taken out and allowed to cool. A blue glass film without cracks was formed. <Refractory coating> As the aggregate, one obtained by mixing alumina and silica powder and adjusting the expansion coefficient to 9 × 10 ⁻⁶ was used. As the binder, an aqueous chromic acid solution having the following composition was used. Chromic acid composition Made by adding 6 parts by weight of CrO _{3 to} 4 parts by weight of water. The mixing ratio of the aggregate and the binder was 2.2 parts by weight of the aggregate and 1.1 parts by weight of the binder, and the mixture was mixed to form a paste and applied to the glass surface. Dry at room temperature, 100 ℃
Hold for 1 hour, then heat up to 550 ° C over 4 hours,
It was kept at 550 ° C. for 3 hours and cooled in the furnace. There was a tightly adhered ceramic coating. <Evaluation test> Samples are placed in a refuse incinerator (temperature 50
It was hung at 0 to 600 ° C. for 6 months to examine the corrosion state. The corrosion condition of the base material was investigated. No corrosion was observed on the substrate under the glass coating, but the side surface of the substrate not covered with the glass was corroded. Further, as in Example 1, the resin was applied to both end faces of the sample and masked, and the sample was immersed in a 10% hydrochloric acid solution. After leaving for 10 days, the liquid was not colored at all.

Example 3 (Example of joining a base metal and a refractory film through a molten film of glass) <Substrate> The surface of φ20 × 50 mm mild steel was roughened by blasting to prepare a Ni-7% AL alloy. Sprayed with a thickness of 0.3 mm. <Glass coating> The glass paste of Example 1 was applied on the thermal spray coating to be slightly thicker (than in Example 1), and after drying, 55
It was placed in an electric furnace heated to 0 ° C., held for 30 minutes, and immediately taken out of the furnace. A pre-sintered coating of glass powder was formed. <Refractory coating> As the aggregate, one obtained by mixing alumina and silica powder and adjusting the expansion coefficient to 8.5 × 10 ⁻⁶ was used.
Only 50% aqueous solution of aluminum (I) phosphate is used as binder. The mixing ratio of the aggregate and the binder is 2.
The binder was added to 2 parts by weight of 1.1 parts by weight, and the mixture was mixed to form a paste, which was applied on the above-mentioned glass temporary sintered film. After drying at room temperature and holding at 100 ° C for 1 hour,
The temperature was raised to 00 ° C over 5 hours, and the temperature was kept at 900 ° C for 30 minutes to cool the furnace. The pre-sintered glass coating melted and was fused to both the refractory coating and the base metal. The refractory coating was firmly adhered to the substrate via this molten glass. There was no crack in the coating. <Evaluation test> An end face was masked with a resin, and an exposure test was performed in a humidified saturated HCL gas stream atmosphere at room temperature. After being left for 6 months, no rust was generated and no change in weight was observed.

Example 4 (Example of forming a refractory film using a metal alkoxide solution) <Substrate> The surface of mild steel of φ20 × 50 mm is roughened by blasting and Ni-7% AL alloy is 0.3 mm thick. What was sprayed. <Glass coating> The glass paste of Example 1 was applied onto the sprayed coating, dried, put in an electric furnace heated to 900 ° C, held for 30 minutes, and immediately taken out of the furnace. A glass melt coating was formed. <Refractory coating> As the aggregate, one obtained by mixing alumina and silica powder and adjusting the expansion coefficient to 8.5 × 10 ⁻⁶ was used.
As the binder, a commercially available metal alkoxide solution for forming a silica film was used. The compounding ratio of the aggregate and the binder was 2.2 parts by weight of the aggregate to 1.1 parts by weight of the binder, and the mixture was mixed to form a paste, which was applied onto the molten coating film of the glass. It was dried at room temperature, heated to 400 ° C. over 3 hours, kept at 400 ° C. for 30 minutes, and cooled in a furnace. The refractory coating was firmly adhered to the glass. There was no crack in the coating. <Evaluation Test> As in Example 1, the sample was coated with resin on both end faces and masked, and the sample was immersed in a 10% hydrochloric acid solution. After leaving for 10 days, the liquid was not colored at all.

Example 5 (Example of forming refractory film using inorganic metal polymer) <Substrate> Surface of φ20 × 50 mm mild steel is roughened by plast, and Ni-7% AL alloy is 0.3 mm thick. What was sprayed. <Glass coating> The glass frit of Example 2 was applied on the thermal spray coating to be slightly thicker (than in Example 1), and dried at room temperature.
It was dried at 00 ° C. for 1 hour. Next, after putting in an electric furnace kept at 850 ° C. and holding for 10 minutes, it was immediately taken out and allowed to cool. A blue glass film without cracks was formed. <Refractory coating> As the aggregate, one obtained by mixing alumina and silica powder and adjusting the expansion coefficient to 8.5 × 10 ⁻⁶ was used.
As the binder, a commercially available polysilazane solution for forming a silica film was used. The mixing ratio of the aggregate and the binder was 2.2 parts by weight of the aggregate to 1.1 parts by weight of the binder, and the mixture was mixed to form a paste, which was applied onto the glass film. Dry at room temperature and heat up to 400 ° C over 2 hours, 4
It was kept at 00 ° C for 1 hour and cooled in the furnace. The refractory coating was firmly adhered to the glass. There was no crack in the coating. <Evaluation Test> As in Example 1, the sample was coated with resin on both end faces and masked, and the sample was immersed in a 10% hydrochloric acid solution. After leaving for 10 days, the liquid was not colored at all.

Example 6 Substrate: The surface of mild steel of φ20 × 100 mm was shot-plated to roughen the surface, and then the sprayed powder of Example 1 was 0.3.
Sprayed to a thickness of mm. <Coating of glassy ceramic film> A commercially available metal alkoxide solution for forming a SiO ₂ film is applied onto the sprayed film, dried, and heated to 400 ° C. over 2 hours, and then heated at 400 ° C. for 1 hour.
It was held for a while and cooled in the furnace. About 0.5 micron SiO ₂
Was formed. <Refractory coating> CaO-stabilized zirconia ceramic powder (under 45 microns) is used for the aggregate. The binder used had the following composition. A mixture of 1 part by weight of an aqueous solution of zinc chromate having the following composition with 3 parts by weight of a 50% aqueous solution of aluminum (I) phosphate. Composition of zinc chromate 1 part by weight of ZnO was added to a chromic acid solution prepared by adding 5 parts by weight of CrO _{3 to} 4 parts by weight of water. The mixing ratio of the aggregate and the binder is 3.2 parts by weight of the aggregate and 1.1 parts by weight of the binder, and the mixture is mixed to form a paste.
_It was applied to _two films. After drying at room temperature and holding at 100 ° C for 1 hour, the temperature is raised to 550 ° C over 4 hours and then at 550 ° C for 3 hours.
It was held for a while and cooled in the furnace. It was covered with a tightly adherent coating of zirconia ceramic. The adhesion strength did not come off in the tape peeling test. <Evaluation Test> The above-mentioned sample coated with zirconia was coated with a resin and masked, and then subjected to an exposure test in a humidified saturated HCL gas stream atmosphere at room temperature. Three
After being left for a month, no rust was generated and no change in weight was observed.

Example 7 (molten salt immersion test) The ash deposited on the surface of the boiler tube of a refuse incinerator mixed with plastic waste was melted at 700 ° C. in an alumina crucible, and the ash was coated with zirconia of Example 1. The sample, the sample coated only with glass before being coated with zirconia, and the sample coated only with thermal spraying were immersed to examine the melt damage property to the ash melted. The immersion time is 6 months. After the test
Measure the diameter. The sample coated with zirconia had no diameter reduction. Both the sample coated only with glass before coating with zirconia and the sample coated only with thermal spraying were corroded by the molten ash, and melting loss was observed. Only 0.1 to 0.
A reduction of 2 mm diameter was observed. In the glass-coated glass, the glass was almost dissolved in the molten salt and only traces remained. Moreover, the microstructure of the cross section of the zirconia coating was examined. The zirconia coating was not attacked by molten ash (molten salt). Further, the sprayed film under the glass and the iron base material were not corroded at all.

[0022]

The present invention has the following effects. 1. Not affected by hot corrosive gases. 2. Not affected by corrosive liquids. 3. Not affected by hot molten salt. 4. It also has the properties of other ordinary refractories.

Claims (6)

[Claims] 1. A glass film is fused on the surface of a member, and a refractory film bonded with an inorganic binder is coated on the glass film, and the glass film is fused or solid-phased on the refractory film. A refractory coating structure characterized by being bonded together. 2. A member having a structure in which a heat-resistant and corrosion-resistant metal is sprayed on the surface, a glass film is fused on the sprayed layer, and a refractory film bonded by an inorganic binder is formed on the glass film. A refractory coating structure, characterized in that the refractory coating is coated and the glass film is fused or solid-phase bonded to the refractory coating. Wherein the glass bonding layer is as defined in claim 1 or 2, characterized in that it comprises a mixed oxide of Cr 2 _O 3 or Cr ₂ O _3, were generated heat during glass fusion Refractory coating structure. 4. A refractory film structure comprising a glassy ceramic thin film deposited on the surface of a member, and a refractory film bonded with an inorganic binder being solid-phase bonded onto the thin film. 5. A refractory film in which a glass ceramic thin film is deposited on the sprayed layer of a member having a structure in which a heat-resistant and corrosion-resistant metal is sprayed on the surface, and which is bonded to the thin film with an inorganic binder. A refractory coating structure characterized by being solid-phase bonded together. 6. The refractory material according to claim 4 or 5, wherein the inorganic binder contains Cr ₂ O ₃ or a double oxide of Cr ₂ O ₃ generated by heating during solid phase bonding. Coating structure.