JP6544606B1 - Coating material and heat resistant member for preventing adhesion of molten metal and preventing high temperature - Google Patents

Abstract

To provide a covering material which can be easily formed on the surface of a target substrate, can prevent the adhesion thereof by having poor wettability to molten metal and slag, and can prevent heat transfer and temperature increase to the substrate, An object of the present invention is to provide a heat insulating member provided with this covering material. A coating material 2 is coated on the surface of a container body 3 of a sampling container 1 and the like for preventing adhesion of molten metal or slag to these members, and for preventing the temperature rise of the member A coated drier comprising a slurry containing diatomaceous earth, silica fine particles, and an organic binder, wherein the silica fine particles are fumed silica having an average particle diameter of primary particles of 10 to 40 nm, relative to the total solid mass of the slurry The baked diatomaceous earth is contained in 80 to 95% by mass, the silica fine particles in 3 to 7% by mass, and the organic binder in 1 to 3% by mass. [Selected figure] Figure 2

Description

  The present invention relates to a tapping hole and peripheral equipment to which molten metal adheres and high-temperature molten metal scatters in the metal manufacturing industry, or a sampling container (stalk) immersed in molten metal for sampling the molten metal, etc. The present invention relates to a coating material for preventing adhesion of molten metal and prevention of high temperature formation formed on the surface of equipment and members in contact with molten metal, and a heat-resistant member provided with the coating material.

  In the melting process using an electric furnace or a smelting furnace for melting or refining a metal material, sampling is performed for temperature measurement and component analysis of molten metal. In sampling, it is necessary to immerse the sampling container (stalk) and its holder in the molten metal, and these devices used are protected by providing a heat-resistant coating on the surface of the substrate. In addition, in the metal manufacturing industry, in order to prevent adhesion of the metal at the outlet and adhesion of the scattered metal to peripheral equipment due to the scattering of high temperature molten metal, a heat-resistant covering material is provided at these places as described above. . In addition, the excellent heat-resistant coating material helps to prevent the adhesion of the molten metal and also prevent the oxidation deterioration of the used tool substrate by preventing the heat transfer and the temperature increase to the substrate which coats it.

  As an example of a heat-resistant covering material, there is known an inhibitor which prevents spatters scattered when welding steel materials from adhering to the periphery of a welding portion. For example, Patent Document 1 includes at least one selected from the group consisting of fine powders of inorganic substances and inorganic compounds, water, dicarboxylic acids, metal hydroxides, triazoles, chelating agents, saturated fatty acids, and unsaturated fatty acids. A weld spatter anti-adhesion agent is proposed which contains a substance and further contains an aqueous solution of sodium silicate (water glass) as an inorganic binder and the like (see Patent Document 1).

  In addition, as an inhibitor for the same purpose, Patent Document 2 proposes a weld spatter adhesion inhibitor prepared by mixing water with fine particles of vitreous volcanic debris such as Shirasu (see Patent Document 2). ). This inhibitor is said to be capable of forming a coating film having high uniformity and uniformity on a member to be welded by utilizing the good spreadability and adhesiveness of natural vitreous pyroclastic materials.

  In general, in heat-resistant coating materials, metal adheres to each use, so while checking the adhesion situation after one or several uses, sweep away the adhered metal by the start of the next work, scrape off, wash it out, etc. Need to be removed.

JP 2005-324217 A JP, 2013-75324, A

  However, since the above removal operation is mainly manual operation, it requires considerable time and labor, making the operation cost of the equipment expensive. In addition, due to the declining birthrate and the aging of the population, there is an urgent need to reduce the number of workers, reduce the amount of labor per person, and streamline work. Furthermore, in the case of sampling, the operator must take a metal sampling container and quickly finish pouring within the time that the sample collected up to the mold maintains sufficient fluidity, which is dangerous. It is work. In most cases, the metal sample from the previous operation is attached to the metal container used, which also adversely affects the safety of the operation.

  In Patent Document 1, when an inorganic binder such as water glass is used, affinity (wettability) with molten metal or slag due to vitrification of the inorganic binder is recognized, and compared with the case where the inorganic binder is not contained, molten metal or Slag may easily adhere, and the number of times of repeated use may decrease. Also, the inhibitor of Patent Document 2 is easy to coat, but is covered and fixed only by the tackiness of the vitreous volcanic debris, so under conditions where thermal shock or mechanical impact is applied , There is a risk of peeling easily. In addition, when sufficient heat insulation can not be ensured, sticking of the deposited molten metal is likely to occur, and there is also a possibility that the parts may be deformed due to high temperature oxidation. As a result, the removal work can not be reduced or the work can not be streamlined, and there is also a possibility that the safety of the work can not be sufficiently secured.

  The present invention has been made to address such problems, and can be easily formed on the surface of a target substrate, and by having poor wettability to molten metal and slag, these adhesions can be prevented, and An object of the present invention is to provide a covering material capable of preventing heat transfer to the substrate and a temperature rise, and a heat insulating member provided with the covering material.

  The coating material of the present invention is a coating material for coating the surface of a target substrate, for preventing adhesion of molten metal or slag to the target substrate, and for preventing the temperature of the target substrate from rising. The coating material is a coated dry material comprising a slurry containing calcined diatomaceous earth, silica fine particles, and an organic binder, and the silica fine particles are fumed silica having an average particle diameter of primary particles of 10 to 40 nm. I assume. In particular, the coating material is characterized in that it does not contain an inorganic adhesive.

  It is characterized in that 80 to 95 mass% of the calcined diatomaceous earth, 3 to 7 mass% of the silica fine particles, and 1 to 3 mass% of the organic binder are contained with respect to the total solid mass of the slurry.

  The organic binder is characterized in that it is at least one selected from starch, polyvinyl acetate and polyvinyl alcohol.

  The coating material is characterized in that it contains at least one selected from silicone resin, aluminum phosphate, and synthetic resin fiber.

  The heat-resistant member of the present invention is a heat-resistant member comprising a substrate and a covering material coated on the surface thereof, and the covering material is the covering material of the present invention.

  The coating material of the present invention is a coated drying material comprising a slurry containing calcined diatomaceous earth, silica fine particles, and an organic binder, and the silica fine particles are fumed silica having an average particle diameter of primary particles of 10 to 40 nm. Therefore, it can be easily formed in close contact with the surface of the target substrate, has poor wettability to molten metal and slag, and can prevent their adhesion. Further, it is possible to prevent heat transfer and high temperature to the base material, to prevent the adhesion of the molten metal to occur, and to prevent deformation of parts serving as the base material due to high temperature oxidation. As a result, the limit of repeated use without removing the attached metal and the like is significantly increased, the removal operation can be reduced and the operation can be rationalized, and the safety of the operation can be easily secured.

  In addition, since 80 to 95% by mass of calcined diatomaceous earth, 3 to 7% by mass of silica fine particles, and 1 to 3% by mass of organic binder are contained with respect to the total solid mass of the above-mentioned slurry, It is excellent in wettability, and the control performance of heat transfer and high temperature to the substrate.

  Since the organic binder is at least one selected from starch, polyvinyl acetate, and polyvinyl alcohol, these organic binders have a small amount of strong adhesion and a bond of diatomaceous earth powder and a bond of silica fine particles Stay strong.

  Since the heat-resistant member of the present invention comprises the base material and the above-mentioned covering material coated on the surface, it has poor wettability to molten metal and slag, and can prevent their adhesion. In addition, deformation due to high temperature oxidation can be prevented. Furthermore, the use of inexpensive diatomaceous earth as the main component of the covering material reduces the manufacturing cost.

It is a figure which shows an example of the heat-resistant member (sampling container) of this invention. It is an expanded sectional view of the container part in FIG.

  The covering material of the present invention is a covering material for preventing adhesion of molten metal and preventing high temperature, and is made of molten metal such as a sampling container (stalk) which is immersed in the molten metal for sampling the molten metal and the like. It forms on the member surface which contacts. In addition, it can be used as a tool used under the same conditions as the above-mentioned sampling container, a covering material such as peripheral equipment, a floor and a wall. The coating material of the present invention mainly uses diatomaceous earth as a material, positively uses an organic binder as its binder, and uses a material containing predetermined silica fine particles (fumed silica). There is a feature.

  Conventionally, the organic binder has significantly lower heat resistance and fire resistance than the inorganic binder, and when a coating material using the organic binder as a binder is immersed in a molten metal, the organic substance burns violently and burns away at the same time, It has been thought to cause a fierce splash. Therefore, a method is generally employed to reduce the amount used as much as possible. In the present invention, a method in which diatomaceous earth is used as the main component of the coating material and an organic binder is intentionally used as the binder is adopted. Although the heat resistance and fire resistance of an organic binder alone are low, its adhesion is strong, and therefore, when used as a binder for porous diatomaceous earth, the binding of diatomaceous earth powder is strongly maintained. . Moreover, it becomes useful also when combining these diatomaceous earth powder and the silica particle to mix | blend in a coating material. In addition, by not using an inorganic binder (inorganic adhesive, particularly sodium silicate), affinity with molten metal and slag due to vitrification of the inorganic binder is not recognized.

  As described above, in the case of sampling of molten metal, the coating material of the present invention is a molten metal at a high temperature, while it is necessary for the operator to perform a quick operation within the time that sufficient fluidity of the sample is maintained. When immersed in the medium metal, the metal does not stick to the surface of the coating because heat transfer is impaired at the contact interface. This is because the diatomaceous earth shell has fine needle-like projections on the surface as well as the pores, so there are very few contact parts with the molten metal, and heat-resistant members such as containers, tools, instruments and parts to be coated The cooling from the base material is reduced and the flowability can be maintained.

  This means, for example, that it takes time in the sampling operation, and the operator can secure safety. In addition, since the base material itself is protected by being able to prevent the lean oxidation of the collection container to be used, the thickness does not have to be particularly large because it is protected, and weight reduction is possible, which also reduces the burden on workers. . In addition, it is also possible to prevent defects such as fixation of the molten metal and deformation due to high temperature oxidation in advance, and it is also possible to reduce the burden of maintenance.

An example of a covering material using the covering material of the present invention and a heat insulating member provided with the covering material will be described based on FIGS. 1 and 2. FIG. 1 is a schematic view showing an example of a heat-resistant member (sampling container) of the present invention, and FIG. 2 is an enlarged cross-sectional view of a container portion in FIG.
The sampling container 1 is a so-called stalk. As shown in FIG. 1, the sampling container 1 has a structure in which a container main body 3 is fixed to the tip of a long holder 4 by welding or the like. The sampling container 1 is immersed in a molten metal during sampling for temperature measurement or component analysis of molten metal in a melting process using an electric furnace or a smelting furnace for melting or refining a metal material.

  As shown in FIG. 2, the coating material 2 is formed on the surface of the sampling container 1. At the time of sampling, the container body 3 is immersed in the molten metal together with the holder 4 to draw out the molten metal 5. For this reason, the covering material 2 is covered over the whole of these surfaces. The coating material 2 is formed by spraying a predetermined slurry on the container body 3 and the holder 4 made of metal, applying the slurry by printing, dipping, or the like, and then drying the water. In this case, natural drying or forced drying may be used, and in the case of the sampling container as shown in the figure, it can be used immediately by holding it directly on the furnace.

  The covering material 2 is a covering drying material with a slurry containing diatomaceous earth, silica fine particles, and an organic binder, and the silica fine particles are fumed silica having an average particle diameter of primary particles of 10 to 40 nm. In particular, the covering material 2 is composed of calcined diatomaceous earth as a main component, to which an essential small amount of predetermined silica fine particles is additionally added, and this is bound with an organic binder. Moreover, a "coating drying material by slurry" is a member which coats the above-mentioned slurry to a substrate, and it makes it dry.

  The covering material 2 preferably contains 80 to 95% by mass of calcined diatomaceous earth, 3 to 7% by mass of silica fine particles, and 1 to 3% by mass of an organic binder based on the total solid mass of the slurry. Preferably, 88 to 95% by mass of calcined diatomaceous earth, 3 to 7% by mass of silica fine particles, and 1 to 3% by mass of organic binder based on the total solid mass of the slurry. More preferably, the amount of calcined diatomaceous earth is 90 to 93% by mass, the amount of silica fine particles is 5 to 7% by mass, and the amount of organic binder is 1 to 3% by mass, based on the total solid mass of the slurry.

  Moreover, when the silicone resin, aluminum phosphate, and synthetic resin fiber which are mentioned later are included in a slurry, it is preferable that these shall be 5 mass% or less with respect to the total solid mass of a slurry in total. In addition, when the silicone resin is coated on the surface of the coating material, the slurry itself does not include this. In addition, as minor components, dispersion assistants, inorganic assistants (excluding inorganic adhesives) and the like may be included.

  Also, as described above, when the slurry contains solids other than the calcined diatomaceous earth, the silica fine particles, and the organic binder, the calcined diatomaceous earth is 80 to the total solid mass of these three components in the slurry. It is preferable that 95% by mass, 3 to 7% by mass of the silica fine particles, and 1 to 3% by mass of the organic binder are contained, respectively. Preferably, based on the total solid mass of these three components in the slurry, the amount of calcined diatomaceous earth is 88 to 95% by mass, the amount of silica fine particles is 3 to 7% by mass, and the amount of organic binder is 1 to 3% by mass.

  Diatomaceous earth is a deposit of fossil diatoms, which is a type of algae, and its main component (85% by weight or more) is silicon dioxide. This contains alumina, iron oxide and other components slightly. Diatomaceous earth is used after being crushed to such an extent that the shell is not broken. There are many fine pores in the diatom shell, and diatomaceous earth has a very small weight per volume. As described above, since diatomaceous earth has a large amount of fine pores in its shell and is a porous powder having a very small area of true contact with a high temperature molten metal, it is excellent in heat insulation and fire resistance. Calcined diatomaceous earth is obtained by calcining diatomaceous earth. Compared to uncalcined diatomaceous earth, there are less impurities and better heat resistance. Moreover, it is preferable that it is 10-40 micrometers, and, as for the average particle diameter (50% average particle diameter by laser method) of the baking diatomaceous earth which can be used by this invention, it is more preferable that it is 10-20 micrometers.

  As the silica fine particles, fumed silica having an average particle size of primary particles (50% average particle size by laser method) of 10 to 40 nm is used. This silica is obtained by calcining the raw material silicon chloride at high temperature. Such silica includes, for example, amorphous silica obtained by vaporizing silicon tetrachloride and synthesizing it by gas phase reaction in an extremely high temperature (1000 ° C. or higher) hydrogen flame. Fumed silica has hydrophilic silanol groups (Si-OH) on its surface. Moreover, since it does not shift to a liquid phase at the time of manufacture and is a loose aggregate, it is excellent in dispersibility in water. As fumed silica, there are hydrophobic silica fine particles obtained by chemically reacting surface silanols, but in the present invention, hydrophilic silica fine particles (non-hydrophobic silica fine particles) which do not modify such surface silanol groups are used. Is preferred.

  In addition to the calcined diatomaceous earth and the organic binder, the silica fine particles together with the organic binder enter into the gaps between the diatomaceous earth powder by using the silica fine particles in combination, and the poor wettability is improved, and the slurry drips at the time of coating formation Can be prevented.

  The organic binder is not particularly limited, and, for example, starch, polyvinyl acetate, polyvinyl alcohol, an elastomer, casein and the like can be used. In particular, it is preferable to use starch, polyvinyl acetate or polyvinyl alcohol in view of availability and the like. These organic binders have strong adhesion in small amounts.

  Because the adhesive strength of the organic binder is strong, the porous diatomaceous earth bonded thereto holds the heat insulation long to prevent the temperature rise of the organic binder, and also prevents the oxygen of the outside air from reaching the organic binder, It is considered that the firing is delayed. This effect is considered to be similarly exhibited in molten metal. Further, unlike molten metal, since the molten metal hardly contains oxygen unlike the atmosphere, the organic binder is heated at high temperature in the atmosphere without oxygen. In such heating, the organic binder is carbonized rather than burned. Hydrogen and oxygen contained in the organic binder by dry distillation become water and carbon dioxide and are volatilized. However, since a relatively large amount of carbon component is contained, the remaining carbon remains in a reduced state, and the diatomaceous earth and the silica fine particles are maintained in a bound state until it is dissolved in the molten metal. Therefore, the state in which the diatomaceous earth and the silica fine particles are bonded continues for a long time, and has excellent durability as a coating material.

  Moreover, when it immerses in molten metal, when an organic binder is used for a coating material, generation | occurrence | production of a splash is less than the case where an inorganic binder is used. This is because the organic binder has high adhesive strength and the amount thereof used is small, so the amount of gas generated by dry distillation of the organic binder is also small. The generated gas passes through the fine gaps between the porous diatomaceous earth shell and the silica fine particles remaining on the outside, and becomes fine bubbles and spouts into the molten metal. Thus, it is considered that the generation of splash is suppressed because the amount of gas generation is small and the fine bubbles are ejected into the molten metal.

  In addition, the covering material can include at least one selected from silicone resin, aluminum phosphate, and synthetic resin fiber. The silicone resin is not, for example, blended in a slurry, but is coated as a surface covering material. When the insulating material is used in an environment where there is moisture, but not when it is used at high temperatures, the surface is coated with a silicone resin after the formation of the coating material, so that the absorption of moisture by the coating material can be prevented.

  As aluminum phosphate, primary aluminum phosphate can be used. Further, as synthetic resin fibers, polyolefin resin fibers such as polypropylene resin, nylon fibers and the like can be used. These are blended as needed to reinforce the coating material. In addition, as minor components, clay minerals such as attapulgite, bentonite, montmorillonite, and inorganic fibers such as glass fibers, ceramic fibers, carbon fibers, etc. may be blended.

  The slurry for forming the covering material 2 can be obtained, for example, by first dispersing silica fine particles and an organic binder in water using each material to form a solution, and adding calcined diatomaceous earth thereto and kneading. The ratio of water to solid content is about (water: solid content) = (1: 2) to (1: 5), and can be appropriately adjusted depending on the application, shape, and the like of the target substrate of the covering material. The slurry is used to adhere to the target substrate by spraying, printing, dipping or the like, and then the moisture is dried to form a coating material.

  This covering material can be formed on the surface of the target substrate of various materials such as metal, plastic, concrete and the like. The adhesive of a strong organic binder functions on the adherend surface, and the diatom shell itself of the heat insulator itself functions as an aggregate, so that strong bonding is possible.

  In the present invention, calcinated diatomaceous earth and silica fine particles finer than this are used in combination as a slurry to which an organic binder is added, and in the covering material obtained after coating and drying, the shell of calcined diatomaceous earth is the surface of the covering material It has a uniform alignment, has primarily poor wettability, and has a high-temperature molten metal wetting angle of 150 degrees or more. In addition, the fine silica particles enter into the gaps between the diatomaceous earth powder, thereby improving the poor wettability and preventing the liquid dripping at the time of coating. Diatomaceous earth is literally a siliceous diatom shell, and diatoms are fossilized under the influence of dissolved silica in the surface water for many years, and their formation and structure are different from those of other hydrous metal silicate minerals. Have. For this reason, there is no permeation of metal ions from the high temperature molten metal and it has different properties from other minerals. The metal and slag can be removed very easily because they are less susceptible to active free electrons in the high temperature molten metal and less miscible at the interface of the coating layer. In particular, since the diatom shell is a porous body, it can prevent high temperature oxidation of the equipment used and prevent deterioration of the equipment and, conversely, prevent heat radiation of the molten metal, thus enabling safe operation over time. Become.

  In addition, the covering material of the present invention can be applied to the metal heat insulation door of a commercial refrigerator, ensures excellent heat insulation, and can be significantly reduced in weight as compared with a conventional tree such as pine wood. In addition, it has excellent soundproofing and can be used as a soundproof door. In addition, since the firing speed is almost zero, it is possible to prevent the spread of fire even in the case of a fire. In addition, the working metal ladders and passages on the furnace during high-temperature melting have sufficient heat transmission so that the bottom of the safety shoes melts due to the radiant heat of the high-temperature molten metal, and re-radiation from those metals There are cases where the temperature is raised and the working environment is poor. By coating the coating material of the present invention on the surface of the passage in the direction of strong heat propagation, the surface temperature can be made a surface temperature that can be touched with bare hands, and the temperature drop in the work place is 10 ° C or more for a long time Can be expected over.

Test Example 1
As a heat-resistant member of the present invention, a member having a covering material on the surface of an iron handle was produced. First, a slurry in which calcined diatomaceous earth, fumed silica (average particle diameter: 40 nm), and polyvinyl acetate as an organic binder are dispersed in water was obtained as a slurry for forming a covering material. This slurry was adjusted to contain 93% by mass of calcined diatomaceous earth, 5% by mass of fumed silica, and 2% by mass of polyvinyl acetate, based on the total solid mass. Moreover, the weight ratio of solid content to water was 1: 3. After immersing the container body portion of the stalks in this slurry, it was allowed to air dry for several minutes to form a coating.
The operation of pouring the molten pig iron at 1500 ° C. into the mold was carried out a plurality of times using this pelvis at constant intervals, and damage to the surface of the pelvis and adhesion of the pig iron were observed. As a result of the observation, no damage or adhesion of pig iron was observed on the surface of the pelvis even after 10 times of implementation.

Test example 2
As a heat-resistant member of the present invention, a member having a covering material on the surface of an iron handle was produced. First, a slurry in which calcined diatomaceous earth, fumed silica (average particle diameter: 40 nm), and polyvinyl acetate as an organic binder are dispersed in water was obtained as a slurry for forming a covering material. This slurry was adjusted to contain 90% by mass of calcined diatomaceous earth, 7% by mass of fumed silica, and 3% by mass of polyvinyl acetate, based on the total solid mass. Moreover, the weight ratio of solid content to water was 1: 3. After immersing the container body portion of the stalks in this slurry, it was allowed to air dry for several minutes to form a coating.
The operation of pouring the molten pig iron at 1500 ° C. into the mold was carried out a plurality of times using this pelvis at constant intervals, and damage to the surface of the pelvis and adhesion of the pig iron were observed. As a result of the observation, no damage or adhesion of pig iron was observed on the surface of the pelvis even after 12 times of implementation.

Test Example 3
As a heat-resistant member of the present invention, a member having a covering material on the surface of an iron handle was produced. First, a slurry in which calcined diatomaceous earth, wet silica, and polyvinyl acetate as an organic binder were dispersed in water was obtained as a slurry for forming a covering material. The slurry was adjusted to contain 93% by mass of calcined diatomaceous earth, 5% by mass of wet silica, and 2% by mass of polyvinyl acetate, based on the total solid mass. Moreover, the weight ratio of solid content to water was 1: 3. After immersing the container body portion of the stalks in this slurry, it was allowed to air dry for several minutes to form a coating.
The operation of pouring the molten pig iron at 1500 ° C. into the mold was carried out a plurality of times using this pelvis at constant intervals, and damage to the surface of the pelvis and adhesion of the pig iron were observed. As a result of observation, adhesion of pig iron was observed after 7 times of implementation.

Test Example 4
As a heat-resistant member of the present invention, a member having a covering material on the surface of an iron handle was produced. First, as a slurry for forming a covering material, a slurry obtained by dispersing calcined diatomaceous earth, fumed silica (average particle diameter 40 nm), polyvinyl acetate as an organic binder, and sodium silicate as an inorganic binder in water is used. Obtained. The slurry was adjusted to contain 90% by mass of calcined diatomaceous earth, 5% by mass of fumed silica, 2% by mass of polyvinyl acetate, and 3% by mass of sodium silicate, based on the total solid mass. Moreover, the weight ratio of solid content to water was 1: 3. After immersing the container body portion of the stalks in this slurry, it was allowed to air dry for several minutes to form a coating.
The operation of pouring the molten pig iron at 1500 ° C. into the mold was carried out a plurality of times using this pelvis at constant intervals, and damage to the surface of the pelvis and adhesion of the pig iron were observed. As a result of observation, adhesion of pig iron was observed after 5 times of implementation.

  The coating material of the present invention can be easily formed on the surface of the target substrate, and can be prevented from adhering to the substrate by having low wettability to molten metal and slag, and can prevent heat transfer and temperature increase to the substrate Therefore, in the metal manufacturing industry, contact with molten metal, such as a tapping hole and peripheral equipment to which molten metal adheres and high-temperature molten metal scatters, or a sampling container immersed in molten metal for sampling of molten metal, Can be widely used as a covering material for equipment and components.

1 Sample Collection Container (Shipstick)
2 Coating material 3 Container body 4 Holder 5 Molten metal

Claims (4)

A coating material for covering the surface of a target substrate, for preventing adhesion of molten metal or slag to the target substrate, and for preventing the temperature of the target substrate from rising.
The covering material is a covering drying material with a slurry containing calcined diatomaceous earth, silica fine particles, and an organic binder,
The coating does not contain sodium silicate, which is an inorganic adhesive,
The silica fine particles, Ri fumed silica der average particle diameter of primary particles is 10 to 40 nm,
Coating material comprising 80 to 95 mass% of the calcined diatomaceous earth, 3 to 7 mass% of the silica fine particles, and 1 to 3 mass% of the organic binder, based on the total solid mass of the slurry .   The coating material according to claim 1, wherein the organic binder is at least one selected from starch, polyvinyl acetate, and polyvinyl alcohol. The covering material according to claim 1 or 2 , wherein the covering material contains at least one selected from silicone resin, aluminum phosphate, and synthetic resin fiber. A heat-resistant member comprising a substrate and a coating material coated on the surface, comprising:
The heat-resistant member, wherein the covering material is the covering material according to any one of claims 1 to 3 .

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