JP7247141B2 - Heat storage element and method for manufacturing heat storage element - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage body that is arranged in a gas flow path and exchanges heat with gas, and a method for manufacturing the heat storage body.

As an example of the heat storage body arranged in the gas flow path to exchange heat with the gas, there is a heat storage body arranged in the heat exchange section of a regenerative burner (regenerative burner). Regenerative burners are used in industrial furnaces such as forging furnaces, heat treatment furnaces, melting furnaces, and firing furnaces. The flow direction of the gas is switched at predetermined time intervals so as to alternately flow the gas and the gas through the heat exchange section. The heat exchange section is filled with a large number of heat storage bodies, the heat of the exhaust gas is recovered by the heat storage bodies, and the recovered heat preheats the newly supplied gas.

Solid balls made of alumina have been widely used as heat storage bodies. On the other hand, there has also been proposed a technique of using a ceramic honeycomb structure of alumina, cordierite, mullite, or the like as a heat storage medium (see, for example, Patent Document 1).

In addition, the present applicant has proposed a heat storage body having a silicon carbide ceramic sintered body as a base (see Patent Document 2). Silicon carbide is a material with high thermal conductivity among ceramics. Specifically, alumina, cordierite, and mullite have thermal conductivities of 9 to 30 W/m K, 0.6 W/m K, and 1.5 W/m K, respectively. , the thermal conductivity of silicon carbide is as high as 75 to 130 W/m·K. Therefore, the heat storage element based on the silicon carbide ceramic sintered body has high heat exchange efficiency.

In addition, silicon carbide has a small thermal expansion coefficient of 4.0 to 4.5 (×10 ⁻⁶ K). That is, since silicon carbide has a high thermal conductivity and a small thermal expansion coefficient, it is excellent in thermal shock resistance. Therefore, a heat storage body having a silicon carbide ceramic sintered body as a base is suitable as a heat storage body that continues to undergo temperature changes due to repeated heat storage and heat dissipation.

However, silicon carbide has the problem of being oxidized when used at high temperatures in an oxygen-containing atmosphere. Therefore, in the technique of Patent Document 2, a means of forming an anti-oxidation layer of silicate glass on the surface of a substrate, which is a silicon carbide ceramic sintered body, is employed. This silicate-based glass layer prevents contact between the silicon carbide of the substrate and oxygen, thereby effectively suppressing oxidation of the silicon carbide.

In addition, as a result of examination by the present applicant, it has been found that the thermal shock resistance is further enhanced by providing the anti-oxidation layer of silicate glass, compared to silicon carbide, which originally has high thermal shock resistance. It is believed that this is because silicic acid glass has the property of softening and plastically deforming at high temperatures, which suppresses the extension of cracks and suppresses the brittle fracture of the silicon carbide ceramic sintered body. .

However, while the property of silicate glass to soften at high temperatures is an advantage as described above, the softened glass sometimes causes the heat storage elements to adhere to each other or the heat storage element and the casing to adhere to each other. When such adhesion occurs, there arises a problem that it is difficult to perform maintenance such as exchanging the heat storage body or removing the heat storage body from the heat storage section and cleaning it. Further, when the heat storage medium is a solid ball, the above-mentioned adhesion clogs the air gaps through which the gas should pass, and there is a problem that the heat exchange rate is lowered.

Japanese Patent Application Laid-Open No. 2003-287379 Japanese Patent No. 5709007

Therefore, in view of the above circumstances, the present invention provides a heat storage body having an anti-oxidation layer made of silicate glass and suppressing adhesion between the heat storage bodies or between the heat storage body and the casing, and the heat storage body. An object of the present invention is to provide a method for manufacturing a heat storage element.

In order to solve the above problems, the heat storage body according to the present invention is
"A base of a silicon carbide ceramic sintered body,
an antioxidant layer of silicate glass covering the surface of the substrate;
an anti-adhesion layer covering at least a portion of the anti-oxidation layer from the outside,
The anti-adhesion layer contains a highly refractory material that is an oxide ceramic with a melting point of 1600° C. or higher."

The heat storage element having this configuration can be manufactured by the following method for manufacturing a heat storage element. i.e.
"A first coating step of coating the surface of a substrate formed of a silicon carbide ceramic sintered body with an antioxidant containing silicon dioxide;
a first heat treatment step in which the substrate that has undergone the first coating step is heated to melt the silicon dioxide and then cooled so that the antioxidant is used as an antioxidant layer of silicate glass;
A second step of coating at least part of the surface of the substrate that has undergone the first heat treatment step from the outside of the antioxidant layer with an anti-adhesion agent containing a highly refractory oxide ceramic material having a melting point of 1600° C. or higher. a coating process;
The substrate that has undergone the second coating step is heated to soften the silicate-based glass of the anti-oxidation layer to adhere the highly refractory material, and then cooled to solidify the silicate-based glass, thereby preventing oxidation. a second heat treatment step of fixing the anti-adhesion layer to the layer;
"equipped with

A highly refractory material, which is an oxide ceramic having a melting point of 1600° C. or higher, does not soften at a temperature at which silicate glass softens. Therefore, on the surface of the heat storage element, the surface in contact with the adjacent heat storage element and the surface in contact with the casing are covered with an anti-adhesion layer containing a highly refractory material from the outside of the anti-oxidation layer of silicic acid glass, so that the silicic acid It is possible to effectively suppress the adhesion between the heat storage bodies and the adhesion between the heat storage body and the casing due to the softening of the system glass.

In addition to the configuration described above, the heat storage element according to the present invention can be configured such that "the highly refractory material is zircon, mullite, or a mixture of zircon and mullite."

Since zircon and mullite contain a silicon (Si) component, they have the advantage of being highly compatible with the antioxidant layer of silicate glass. In addition, since zircon and mullite have coefficients of thermal expansion close to those of silicon carbide, when the heat storage medium is repeatedly used for heating (heat storage) and cooling (heat dissipation), the thermal expansion between the substrate and the anti-adhesion layer is reduced. difference is small, and there is an advantage that cracks are less likely to occur in the anti-adhesion layer.

In addition to the above configuration, the heat storage element according to the present invention has
"The substrate is a honeycomb structure comprising a plurality of cells partitioned by partition walls extending in a single direction,
Whereas the antioxidant layer covers the inner surface of the cell,
The anti-adhesion layer does not cover the anti-oxidation layer on the inner surface of the cell.

In this configuration, the substrate is a honeycomb structure. A honeycomb structure has cells partitioned by a large number of partition walls, and the cells extend in a single direction. Therefore, the honeycomb structure has the advantage that pressure loss associated with gas circulation is small. In addition, since the honeycomb structure has a much larger surface area than solid balls, it has the advantage of having a large area that contributes to heat exchange as compared to solid balls.

In this structure, the inner surface of the cell among the surfaces of the substrate has an anti-oxidation layer, but does not have an anti-adhesion layer. This is because an anti-adhesion layer is not necessary on the inner surface of the cell in order to prevent adhesion between the heat storage bodies and between the heat storage body and the casing. Further, in the case of the honeycomb structure heat storage body, it is the internal space of the cells that the gas that exchanges heat with the heat storage body flows. Therefore, since an anti-adhesion layer is not formed on the inner surface of the cell, there is no possibility that the presence of the layer of the highly refractory material will impair the heat exchange effect of the heat storage body.

As described above, according to the present invention, there is provided a heat storage body having an anti-oxidation layer made of silicate glass and suppressing adhesion between the heat storage bodies or between the heat storage body and the casing, and the heat storage body. A method of manufacturing a body can be provided.

1 is a perspective view of a heat storage body that is an embodiment of the present invention; FIG. FIG. 2 is a transverse cross-sectional view of the heat storage body of FIG. 1 (a cross-sectional view taken along a plane perpendicular to the axial direction of the cell). FIG. 10 is a cross-sectional view of a heat storage body of another embodiment cut at the center;

A heat storage element 1, which is a specific embodiment of the present invention, and a method for manufacturing the same will be described below. The base 10 of the heat storage element 1 of the present embodiment is a honeycomb structure having a plurality of cells 15 partitioned by partition walls 11 extending in a single direction and formed of a silicon carbide ceramic sintered body. It is

The surface of the substrate 10, that is, both end surfaces S1 where the cells 15 are open, the outer peripheral surface S2 (the surface where the cells 15 are not open), and the inner surface of the cells 15 are coated with an antioxidant layer 21. there is The antioxidant layer 21 is a layer of silicate glass. An anti-adhesion layer 22 is laminated on the outer side of the anti-oxidation layer 21 on both the end surface S1 and the outer peripheral surface S2 of the surface of the substrate 10 . The anti-adhesion layer 22 is a layer containing a highly refractory material that is an oxide ceramic with a melting point higher than 1600°C.

The heat storage element 1 having such a structure is manufactured by a first coating step of coating the surface of the silicon carbide ceramic sintered body 10 formed in a honeycomb structure with an antioxidant, and a step of applying the antioxidant to a silicate glass. a second coating step of coating an anti-adhesion agent on both the end surface S1 and the outer peripheral surface S2 of the surface of the substrate 10; and a second heat treatment step for bonding to 21 .

More specifically, the first coating step is a step of applying or spraying an antioxidant onto the surface of the substrate 10, a step of immersing the substrate 10 in the antioxidant, or a step of impregnating the substrate 10 with the antioxidant. can be

The antioxidant is a slurry that becomes silicate glass when heated, and is obtained by mixing a source of silicon dioxide with a liquid medium such as water and a binder. As the source of silicon dioxide, silica powder, glass powder (glass frit), and clay can be used singly or in combination. In addition to the above components, the raw material of the antioxidant may contain other components. By adding boron oxide (B ₂ O ₃ ), the viscosity (fluidity) and durability of the glass can be adjusted. Alkali metal oxides (Na ₂ O, K ₂ O, Li ₂ O, etc.) lower the viscosity of the glass and lower the glass transition point. Alkaline earth metal oxides (CaO, MgO, BaO, SrO, etc.) increase the chemical durability of the glass and affect the non-crystallization/crystallization of the glass. Aluminum oxide has the effect of increasing the chemical durability of glass.

The first heat treatment step is a step of melting silicon dioxide by heating and then cooling to a temperature lower than the glass transition point to form silicate glass. In the first heat treatment step, the antioxidant-coated substrate 10 is heated at a temperature of about 100°C in an air atmosphere to perform a drying treatment to remove the liquid medium in the antioxidant, and then heated to 1000°C to 1200°C. and heated for a predetermined time, and then cooled. By this treatment, the silicon dioxide contained in the antioxidant melts and spreads over the surface of the substrate 10, and then solidifies to form silicate glass. is formed in close contact with the surface of the

The second coating step can be a step of applying or spraying an anti-adhesion agent to both the end surface S1 and the outer peripheral surface S2 of the surface of the substrate 10 .

The anti-adhesion agent is a slurry obtained by mixing powder of a highly refractory material with a liquid medium such as water and a binder. High refractory materials are oxide ceramics having a melting point of 1600° C. or higher, such as zircon (ZrSiO ₄ ), mullite (3Al ₂ O ₃ .2SiO ₂ ), zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), A mixture of two or more thereof can be exemplified. The melting points of the above oxide ceramics are shown below.
Zircon: 2430°C
Mullite: 1850°C
Zirconia: 2715°C
Alumina: 1840°C

The second heat treatment step is a step of laminating an anti-adhesion layer 22 on the anti-oxidation layer 21 by adhering particles of a highly refractory material to the anti-oxidation layer 21 of silicate glass. In the second heat treatment step, the substrate 10 coated with the anti-oxidation layer 21 is heated at a temperature of about 100° C. in an air atmosphere to remove the liquid medium in the anti-adhesion agent. The temperature is raised to 1000° C., heated for a predetermined time, and then cooled. By this treatment, the silicate-based glass of the antioxidant layer 21 is softened to some extent, and after the particles of the highly refractory material are adhered, the silicate-based glass is solidified in that state. An anti-adhesion layer 22 of refractory material is laminated.

Through the above steps, the heat storage element 1 having the following configuration can be obtained. That is, a substrate 10 which is a honeycomb structure formed of a silicon carbide ceramic sintered body, an antioxidant layer 21 of silicic acid glass covering the surface of the substrate 10, and a substrate coated with the antioxidant layer 21. 10, the anti-adhesion layer 22 containing a highly refractory material is laminated on the anti-oxidation layer 21 on the end surface S1 where the cell 15 is open and the outer peripheral surface S2.

With such a configuration, even when the heat storage element 1 is used at high temperatures in an oxygen-containing atmosphere, the anti-oxidation layer 21 of silicate glass airtightly covering the surface of the substrate 10 protects the surface of the substrate 10 from silicon carbide ceramics. Certain substrates 10 are prevented from oxidizing.

Moreover, the honeycomb-structured heat storage element 1 is generally used in a state of being vertically and horizontally stacked inside the heat storage section at the site of use. The anti-oxidation layer 21 of silicate glass softens at high temperatures, but on the surfaces of the heat storage elements 1 used in a stacked state, on the end surface S1 and the outer peripheral surface S2 in contact with the adjacent heat storage elements 1 and the casing. , an anti-adhesion layer 22 of a highly refractory material is laminated on the outside of the anti-oxidation layer 21 . Since the highly refractory material does not soften even at high temperatures when the heat storage element 1 is used, the presence of the adhesion prevention layer 22 prevents the heat storage elements 1 from adhering to each other and the heat storage element 1 from the casing.

It is the internal space of the cell 15 that the gas that the heat storage element 1 exchanges heat flows through, and since the layer of the highly refractory material is not laminated on the inner surface of the cell 15, the layer of the highly refractory material is not laminated. There is no fear that the heat exchange effect of the heat storage element 1 will be impaired due to its presence.

Next, the results of examining the anti-oxidation effect and anti-adhesion effect of the heat storage bodies of Examples 1 to 7 are shown.

Substrates prepared under the same conditions were used for the samples of Examples 1-7. This substrate is produced by molding a raw material containing silicon carbide as an aggregate, and a silicon source and a carbon source that generate silicon carbide by reaction, firing the substrate in a non-oxidizing atmosphere, and removing excess carbon in an oxidizing atmosphere. It is removed by heating. The honeycomb structure of the substrate had a partition wall thickness of 0.65 mm, a cell density of 50 cells/inch ² , and a cubic shape of 50 mm×50 mm×50 mm. Pores are formed in traces of disappearance of the carbonaceous material used as the carbon source, and the partition walls are porous.

In order to coat the surface of the substrate of the above embodiment with the antioxidant, the substrate was impregnated with the antioxidant having the same composition under the same conditions (first coating step). In the impregnation treatment, first, the substrate is placed in a container that can be sealed, and the air in the container is sucked by using a vacuum pump or the like. Thereby, the open pores of the porous substrate are degassed. Next, the antioxidant slurry is introduced into the sealed container containing the substrate through a pipe or hose equipped with an on-off valve. As a result, the outer surface of the substrate is coated with the antioxidant, and the antioxidant penetrates into the degassed open pores. Excess antioxidant was then removed from the substrate. Excess antioxidant can be removed, for example, by continuously vibrating the substrate or by blowing compressed air onto the substrate.

The substrates of Examples 1 to 7, the surface of which is coated with an antioxidant, are dried by heating at a temperature of about 100° C., then heated at a temperature of 1000° C. for a certain period of time, and then cooled to room temperature. An antioxidant was used as an antioxidant layer of silicate glass (first heat treatment step).

Next, an anti-adhesion agent was applied to the outer peripheral surface of the substrates of Examples 1 to 7 coated with the antioxidant layer (second coating step). The anti-adhesion agent was prepared by changing the type of refractory material or the average particle size for each example as follows, but under the same conditions other than that.
Example 1: Zircon, average particle size 45 μm
Example 2: Mullite, average particle size 400 μm
Example 3: Mullite, average particle size 20 μm
Example 4: Mixture of zircon and mullite at a mass ratio of 1:1: average particle size 35 μm
Example 5: Zirconia, average particle size 1 μm
Example 6: Alumina, average particle size 120 μm
Example 7: Alumina, average particle size 20 μm

The substrates of Examples 1 to 7, whose outer peripheral surface was coated with an anti-adhesion agent, were dried by heating at a temperature of about 100° C., then heated at a temperature of 1000° C. for a certain period of time, and then cooled to room temperature. A highly refractory material was adhered to the anti-oxidation layer to form an anti-adhesion layer (second heat treatment step).

As comparative examples, heat storage bodies of Comparative Example 1 having only an anti-oxidation layer and Comparative Example 2 having only an anti-adhesion layer were produced. In the heat storage element of Comparative Example 1, the surface of the substrate prepared under the same conditions as the substrate of Example was coated with the same antioxidant as in Example, and the first heat treatment step was performed under the same conditions as in Example to oxidize it. An anti-adhesion layer was not laminated although an anti-adhesion layer was formed. In the heat storage element of Comparative Example 2, the same anti-adhesion agent (highly refractory material: zircon) as in Example 1 was applied to the outer peripheral surface of the substrate prepared under the same conditions as the substrate of Example without applying an antioxidant. was directly applied, heat treatment was performed under the same conditions as the second heat treatment step in the example to form an anti-adhesion layer.

The heat storage bodies of Examples 1 to 7 and Comparative Examples 1 and 2 were subjected to an oxidation test for evaluating oxidation resistance and an adhesion test for evaluating adhesion.

Since the molecular weight of silicon carbide is 40 and the molecular weight of silicon dioxide is 60, when 1 mol of silicon carbide is oxidized to 1 mol of silicon dioxide, the mass increases by 20 g. The oxidation test utilizes this fact and evaluates the degree of oxidation based on the change in mass before and after heat treatment in an air atmosphere. Specifically, the temperature was raised to 1300° C. at a predetermined rate, held at that temperature for 50 hours, and then lowered to room temperature. An oxidation test was performed by Based on the mass before the start of the oxidation test (initial mass), if the rate of increase in mass after the oxidation test is 1% or less, it is evaluated as having oxidation resistance with "○", and the rate of increase in mass is evaluated as "○". When it exceeded 1%, it was evaluated as "x" as being inferior in oxidation resistance.

The adhesion test was carried out by stacking two heat storage elements on each sample so that their outer peripheral surfaces were in contact with each other, holding them at a temperature of 1300° C. for 12 hours, and then cooling them to room temperature. After the test, if the two heat storage bodies could be separated without welding, it was evaluated as "O" because the adhesion was suppressed, and if the two heat storage bodies were welded, it was evaluated as "X" because there was adhesion. ” was evaluated.

In addition, after the oxidation test, the appearance of the heat storage element of each sample was observed with the naked eye, and the case where there were almost no cracks on the outer surface (outermost layer) was indicated by "○", and the case where cracks were slightly observed was indicated by "△". , and the case where cracks were clearly observed was evaluated as "x". The results of the above tests and observations are shown in Table 1.

As shown in Table 1, according to the knowledge obtained so far, Examples 1 to 7 having an antioxidant layer and Comparative Example 1 have oxidation resistance, and Comparative Example 2 without an antioxidant layer. was inferior in oxidation resistance. In addition, the outer surface of Comparative Example 1, in which there is no anti-adhesion layer and the outermost layer is an anti-oxidation layer, was a dense layer with no cracks, as was previously known.

In Examples 1 to 7 and Comparative Example 2, which have an anti-adhesion layer containing a highly refractory material, adhesion between the heat storage elements is effectively suppressed, and this suppressing action depends on the type of highly refractory material and It did not depend on the average particle size.

However, some of the samples in which adhesion between the heat storage bodies was suppressed were found to have slight cracks on the outer surface. Specifically, Example 5, in which the highly refractory material is zirconia, and Example 6 and Example 7, in which both the highly refractory material is alumina but have different average particle diameters. From this, it was considered that the type of high refractory material had a greater effect on the occurrence of cracks on the outer surface than the particle size of the high refractory material. The highly refractory material of Example 1 in which almost no cracks were observed on the outer surface was zircon, the highly refractory material of Examples 2 and 3 was mullite, and the highly refractory material of Example 4 was zircon. and mullite, both of which contain a silicon (Si) component. Therefore, it was thought that the high affinity between the anti-oxidation layer of the silicon-based glass and the anti-adhesion layer of the highly refractory material and the anti-oxidation layer were high, and the occurrence of cracks was suppressed.

In addition, zirconia and alumina have a large difference in coefficient of thermal expansion from silicon carbide. Specifically, the coefficient of thermal expansion of silicon carbide is 4.0 to 4.5 (×10 ⁻⁶ K), while the coefficient of thermal expansion of zirconia and alumina is 10.5 (×10 ^{−6 K} ), respectively. K) and 7.2 (×10 ⁻⁶ K). Therefore, the difference in thermal expansion coefficient between the substrate (silicon carbide ceramic sintered body) and the anti-adhesion layer when the heat storage element is placed at a high temperature is also considered to be one of the causes of cracks in the anti-adhesion layer. rice field. On the other hand, the coefficients of thermal expansion of zircon and mullite, which are highly refractory materials of the sample in which almost no cracks occurred, were 4.5 (×10 ⁻⁶ K) and 5.0 (×10 ⁻⁶ K), respectively. , the coefficient of thermal expansion is close to that of silicon carbide. Therefore, when the heat storage element is placed at a high temperature, the substrate and the anti-adhesion layer thermally expand to the same extent, and when cooled, they thermally contract to the same extent, so that the occurrence of cracks in the anti-adhesion layer is suppressed. I thought there was. In addition, since the silicate glass of the antioxidant layer is softened and elongated by heating, it is considered to follow the thermal expansion of the substrate.

If the surface of the anti-adhesion layer is cracked, the anti-adhesion layer tends to peel off as the heat storage element is used, which may reduce the anti-adhesion effect. Therefore, among oxide ceramics having a melting point of 1600° C. or higher, a material containing a silicon component is suitable as a highly refractory material to be included in the anti-adhesion layer. As the highly refractory material to be included in the anti-adhesion layer, among oxide ceramics having a melting point of 1600° C. or higher, a material having a coefficient of thermal expansion close to that of silicon carbide is suitable. As materials that satisfy both of these two conditions, zircon and mullite are particularly suitable as highly refractory materials to be included in the anti-adhesion layer, and can be used either alone or in combination.

As described above, the present invention has been described with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and as shown below, various improvements can be made without departing from the scope of the present invention. and design changes are possible.

For example, in the heat storage bodies of the examples, the anti-adhesion layer was formed only on the outer peripheral surface of the surface of the substrate coated with the anti-oxidation layer. In addition to the outer peripheral surface of the heat storage element stacked vertically and horizontally in the heat storage section at the site of use, the adhesion prevention layer is formed not only on the end surface where the cell is opened.

Further, when the cross section of the heat storage body of the example was observed with a scanning microscope, it was confirmed that the anti-oxidation layer was a dense layer, while the anti-adhesion layer was a porous layer. From this, it is clear that an anti-oxidation layer of silicic acid-based glass that hermetically coats the substrate is essential in order to suppress oxidation of the heat storage body having a silicon carbide ceramic sintered body as a substrate. It is believed that the gas that exchanges heat with the heat store can access the substrate through the pores of the anti-adhesion layer.

Therefore, in the substrate, which is a honeycomb structure, even if the anti-adhesion layer is laminated on the outside of the anti-oxidation layer on the inner surface of the cells, the presence of the highly refractory material layer impairs the heat exchange effect of the heat storage body. may not be very large. Since the anti-adhesion layer is also laminated on the inner surface of the cell, if foreign matter such as dust is contained in the exhaust gas from which heat is recovered, the foreign matter will adhere to the softened silicate glass and the cell will not be visible. It is possible to prevent the possibility of clogging.

Based on the same idea, as shown in FIG. 3, a heat storage body in which an oxidation prevention layer 21 and an adhesion prevention layer 22 are laminated on a solid ball base 10b formed of a silicon carbide ceramic sintered body. 2. Since the anti-adhesion layer 22 of the highly refractory material is a porous layer, the anti-oxidation layer 21 prevents the heat exchange effect of the heat storage element 2 from being impaired due to the presence of the anti-adhesion layer 22. Oxidation is suppressed, and the presence of the anti-adhesion layer 22 can suppress adhesion between the heat storage bodies, adhesion between the heat storage body and the casing, and adhesion of foreign matter to the heat storage body.

1 heat storage element 2 heat storage element 10 substrate 11 partition wall 15 cell 21 anti-oxidation layer 22 anti-adhesion layer S1 end surface S2 outer peripheral surface

Claims (3)

a base of a silicon carbide ceramic sintered body;
an antioxidant layer of silicate glass covering the surface of the substrate;
an anti-adhesion layer covering at least a portion of the anti-oxidation layer from the outside,
The anti-adhesion layer contains a highly refractory material that is an oxide ceramic with a melting point of 1600° C. or higher ,
The substrate is a honeycomb structure comprising a plurality of cells partitioned by partition walls extending in a single direction,
Whereas the antioxidant layer covers the inner surface of the cell,
The anti-adhesion layer does not cover the anti-oxidation layer on inner surfaces of the cells.
A heat storage element characterized by: 2. The heat storage element of claim 1, wherein the highly refractory material is zircon, mullite, or a mixture of zircon and mullite. a first coating step of coating the surface of a substrate formed of a silicon carbide ceramic sintered body with an antioxidant containing silicon dioxide;
a first heat treatment step in which the substrate that has undergone the first coating step is heated to melt the silicon dioxide and then cooled so that the antioxidant is used as an antioxidant layer of silicate glass;
A second step of coating at least part of the surface of the substrate that has undergone the first heat treatment step from the outside of the antioxidant layer with an anti-adhesion agent containing a highly refractory oxide ceramic material having a melting point of 1600° C. or higher. a coating process;
The substrate that has undergone the second coating step is heated to soften the silicate-based glass of the anti-oxidation layer to adhere the highly refractory material, and then cooled to solidify the silicate-based glass, thereby preventing oxidation. a second heat treatment step of fixing the anti-adhesion layer to the layer;
The substrate is a honeycomb structure having a plurality of cells partitioned by partition walls extending in a single direction,
While coating the inner surface of the cell with the antioxidant layer,
A method for manufacturing a heat storage element, wherein the anti-adhesion layer does not cover the anti-oxidation layer on the inner surface of the cell.

Images