JP2007268119A - Heating implement for microwave oven - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating implement for a microwave oven, which is easily manufactured, capable of exhibiting sufficient strength, and excellent in heat generation and heat insulating performance. <P>SOLUTION: A ceramic sintered body is put into a furnace, and LP gas is fed to perform the carburizing process under high-temperature environment. Then, carbon is deposited on the surface of the ceramic sintered body and into pores constituting a porous structure to form a carbon thin-film layer. The ceramic sintered body with this carbon thin-film layer makes the heating implement for the microwave oven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heating tool for a microwave oven that is used when heat-treating an object to be cooked using a microwave oven.

  The microwave oven irradiates the object to be cooked with microwaves generated from the magnetron, vibrates the water molecules contained in the object to be cooked, and resonates, and heat generated by vibration friction between the water molecules. It heats and cooks foods and is widely used for cooking foods and drinks.

  When the food to be cooked is heated in a microwave oven, a cooking container for storing and placing the food to be cooked is used. As the container, a ceramic container is mainly used. However, since ceramics do not absorb microwaves, they do not generate heat during microwave heating, and the ceramic container itself is not heated.

  Therefore, in the state where the cooked food to be cooked is taken out from the microwave oven, the cooked food is cooled in a relatively short time by the heat of the cooked food being absorbed by the container, and the taste is reduced. There was a bug.

  In order to solve this problem, there is provided a cooking container in which a heating layer made of a substance having a property of absorbing microwaves and generating heat is provided in the cooking container so as to heat not only the food to be cooked but also the container itself. Several proposals have been made.

  As a conventional cooking container of this type, a ceramic material mixed with a heating material such as carbon or carbon black as a microwave absorber and fired, or a heating element made of the heating material, which is plate-shaped There are some which are formed in various shapes such as embedded in ceramic materials and fired (Patent Document 1).

  Further, as a conventional cooking container, there is a ceramic container in which the inside of the structure is a ceramic material containing carbon black, and the outer layer is a ceramic material containing no carbon black and is molded and sintered together with the ceramic material into a container shape (patent) Reference 2).

  However, in the thing of patent document 1, since what mixed exothermic substances, such as carbon and carbon black, with the ceramic material is baked, when there is much mixing amount of exothermic substances, such as carbon, it has an influence on a product physical property. There is a risk that strength will be reduced.

  In addition, because the carbons of the above-mentioned exothermic substances are hydrophobic with respect to the solvent water, they are not mixed uniformly with the ceramic material, and exothermic substances such as carbon are unevenly distributed, so that exothermic substances such as carbon are contained in the ceramic material. It is difficult to distribute uniformly.

  Therefore, when the microwave is irradiated, heat generation material such as unevenly distributed carbon causes local heat generation, thereby causing local thermal expansion and generating stress due to the thermal expansion. As a result, the container is cracked. There are defects that cause cracks and breakage of the container.

  In addition, a heating element formed by molding a heating material into a plate shape or the like is embedded in a ceramic material and fired, and when microwave irradiation, sudden heat generation occurs in the embedded heating element portion, For this reason, a temperature gradient is generated, local thermal expansion occurs, stress is generated due to the thermal expansion, and as a result, there is a drawback that the container is similarly cracked or broken.

  On the other hand, in the case of the one described in Patent Document 2, since the exothermic substance made of carbon black is previously contained in the ceramic material and the exothermic substance-containing material is fired to form a container, the exothermic substance is mixed. When the amount is large, physical properties such as strength may be lowered.

  In addition, since the exothermic material made of carbon black exists only in the inner layer, the exothermic material is unevenly distributed as a whole, and thus locally generates heat when irradiated with microwaves. Therefore, as described above, local thermal expansion occurs. There arises a problem that a stress due to the thermal expansion occurs and the container cracks or the container breaks.

  Furthermore, the methods described in Patent Documents 1 and 2 both have the disadvantage that the manufacturing process is complicated and the manufacturing cost is high.

Japanese Patent Application Laid-Open No. 7-116058 Japanese Patent Laid-Open No. 6-189849

  As described above, in the case of the conventional structure, there is a possibility that the physical properties such as strength may be lowered, the uniform distribution of the exothermic material is difficult, and local heat generation occurs during microwave irradiation, and the container is cracked or broken. There are problems that there is a risk that the manufacturing process will occur, the manufacturing process is complicated, and the manufacturing cost is expensive.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result, the ceramic sintered body is subjected to a carburizing treatment, and the pores constituting the surface of the ceramic sintered body and the porous structure of the ceramic sintered body are formed. Furthermore, if carbon is deposited by vapor phase reaction to form a carbon thin film layer, a layer of a heat generating material is formed on the surface and pores of the ceramic sintered body without causing a decrease in strength as the ceramic sintered body. In addition, the formation of such a carbon vapor-deposited film allows the generation of uniform heat during microwave irradiation, thereby obtaining the knowledge that cracking and destruction of the container can be prevented. It came to complete.

  Therefore, the present invention is free from problems of physical properties such as strength, can generate sufficient and uniform heat during microwave irradiation, has no risk of cracking or breaking of the heating tool, and is easy to manufacture. An object of the present invention is to provide a heating tool.

The present invention
(1) A heating device for a microwave oven comprising a ceramic sintered body, wherein a carbon thin film layer is formed on the surface and pores of the ceramic sintered body by carburizing treatment,
(2) The microwave heater according to (1), wherein the carbon thin film layer is made of carbon obtained by thermal decomposition of hydrocarbons,
(3) The carbon thin film layer by carburizing treatment heats the ceramic sintered body, introduces LP gas, heat-treats in a reducing atmosphere, and deposits carbon on the surface of the ceramic sintered body and in the pores by a gas phase reaction. The heating device for a microwave oven according to (1), which is formed by:
(4) A heating tool for a microwave oven according to (1), wherein a carbon thin film layer is formed in pores at selected sites in the ceramic sintered body,
(5) The selected portion is made into a solid part, a glaze is applied to the other part, carburizing treatment is performed, and the carbon thin film layer is formed in the pores of the ceramic sintered body in the solid part (4) ) Heating device for microwave oven,
(6) A heating device for a microwave oven according to (1) above, which is formed into a container shape.

  In the present invention, a carbon thin film layer is formed on the surface and pores of the ceramic sintered body by carburizing treatment. Therefore, in the stage of manufacturing the ceramic sintered body, it can be manufactured under normal firing conditions. There is no need to adjust the firing conditions as compared with the prior art in which a heating material such as carbon black is mixed and fired in a ceramic material, it is easy to manufacture, and there is no risk that the sintering strength or other physical strength will be reduced. .

  In forming the carbon thin film layer in the present invention, the ceramic sintered body is heated, LP gas is introduced, heat treatment is performed in a reducing atmosphere, and carbon is deposited on the surface and pores of the ceramic sintered body by a gas phase reaction. Thus, when the carbon thin film layer is formed, the exothermic material made of carbon can be uniformly distributed in the ceramic sintered body, and as a result, uniform heat generation is performed during microwave irradiation, and cracking of the container and This has the effect of preventing the occurrence of destruction.

  According to the present invention, since uniform heat generation is performed, it is possible to provide a heating device for a microwave oven that can exhibit a sufficient amount of heat generation as a heating device for a microwave oven and is excellent in heating and heat retention.

  In addition, the present microwave oven heater may be obtained by carburizing the existing product containers, dishes, etc., and the manufacture of the microwave oven heater is extremely simple and There is an advantage that the manufacturing cost can be reduced easily.

  In the present invention, when the selected portion is a solid portion, the glaze is applied to other portions, and the heating device for the microwave oven according to the present invention is configured by performing the carburizing process in a state of performing this kind of partial masking. Can be provided with a high heat-generating part and a low heat-generating part, and can provide an easy-to-use microwave heater when it is held by hand.

  The heating device for a microwave oven of the present invention is made of a ceramic sintered body, and the ceramic sintered body here refers to all ceramics such as earthenware, stoneware, earthenware, and porcelain. Examples of the ceramic material include cordierite, cordierite-mullite, petalite, β-spodumene, alumina, silica, zirconia, and other various chamottes.

  The ceramic material can be selected arbitrarily, but cracks and breakage may occur due to thermal expansion stress due to thermal expansion stress in the case of heating at 120 ° C or higher, rapid heating and quenching, or large and thick items. It is preferable to use petalite, cordierite, cordierite-mullite, or various types of chamotte, which are low expansion ceramics, in order to prevent damage.

  The ceramic sintered body in the present invention is a porous ceramic sintered body and has innumerable fine pores A as shown in FIG. The figure is a cross-sectional photograph (enlarged photograph at a magnification of 100) of a ceramic sintered body by a scanning electron microscope. In the figure, B indicates the surface of the ceramic sintered body, and C indicates the inside.

  The pores A have a continuous pore structure and are formed deep inside the sintered body. The pore-related characteristics such as the shape, size, and porosity of the pore A are determined by the relationship with the amount of carbon deposited by the carburizing process. That is, the amount of carbon deposited in the pores is naturally determined by the pore characteristics. Here, the amount of carbon deposited in the pores of the carburizing process is considered to be proportional to the amount of water permeating phenomenon, so that the above-mentioned pore characteristics can be expressed by the water absorption rate.

  In the present invention, the water absorption as the pore characteristic is preferably 0.2% by weight to 30% by weight. If the water absorption is less than 0.2% by weight, the amount of carbon deposited is not sufficient, the amount of heat generated by microwave absorption is insufficient, and the heating ability for the object to be cooked is insufficient. On the other hand, if the water absorption rate exceeds 30% by weight, the strength of the ceramic sintered body is lowered, and there is a possibility that it cannot be practically used. A more preferable range of water absorption is 0.5% by weight to 5% by weight.

  In the present invention, when manufacturing a ceramic sintered body, a conventional general manufacturing method can be employed. In other words, water is added to the ceramic powder, uniformly wet-mixed by a kneader such as a ball mill, and then molded using a raw material obtained by dehydration. In this molding, a molding method such as press molding, casting molding, roller machine molding or the like is adopted, and a molded product having a desired shape such as a vessel shape is manufactured. The molded article is then fired, whereby a ceramic sintered body is obtained.

  In the present invention, the ceramic sintered body is not limited to a vessel shape, and may be a flat plate shape. When configured as a vessel shape, it can be formed in various shapes such as a container shape and a dish shape.

  The obtained ceramic sintered body is carburized. The carburizing process refers to a ceramic sintered body facing a space in which a gaseous substance containing carbon such as LP gas (liquefied petroleum gas) (hereinafter described using LP gas as an example) is supplied. The gas is heated and thermally decomposed, and carbon is vapor-deposited on the surface of the sintered body (that is, the surface of the particles constituting the base material of the ceramic sintered body) and in the fine pores constituting the porous structure. This is the processing to be performed.

  In this gas phase reaction, carbon is isolated from the pyrolysis gas, and the isolated carbon adheres to the surface and pores of the sintered body and gradually deposits to form a carbon thin film layer (carbon vapor deposition film layer). Thus, carbon deposition is performed.

  For the carburizing process, a furnace having a heating facility and a structure capable of shutting off the outside air is used. The ceramic sintered body is placed in the furnace, for example, on a shelf, and simultaneously, LP gas is supplied into the furnace and burned to heat the ceramic sintered body. When the furnace temperature reaches the specified temperature, heating is stopped, the interior of the furnace is shut off from the outside air, LP gas is supplied in a reducing atmosphere, and this LP gas is brought into contact with the ceramic sintered body heated to a high temperature. Let The LP gas contacts the surface of the ceramic sintered body and also enters and contacts the pores of the sintered body.

  The temperature at the stage of stopping the heating is preferably 1000 ° C to 1100 ° C. LP gas undergoes thermal decomposition when heated under this high temperature atmosphere. That is, pyrolysis of hydrocarbons such as propane and butane, which are the main components of LP gas, occurs, and carbon is isolated from this pyrolysis gas. This isolated carbon adheres to the surface and pores of the sintered body and deposits to form a layer. In this way, carbon is deposited on the surface and pores of the sintered body, and a carbon thin film layer is formed.

  As a furnace used for the carburizing process, for example, a furnace having a structure as shown in FIG. 2 is used.

  In the figure, reference numeral 1 denotes a furnace body, the furnace body 1 has a door (not shown), and a plurality of shelves 2 are installed on the hearth 3 in the furnace body 1. A gas burner 4 for heating is provided in the hearth 3, and the gas burner 4 is connected to an LP gas cylinder 6 through a gas supply pipe 5, and a gas supplied from the LP gas cylinder 6 in the middle of the gas supply pipe 5. A supply gas flow rate adjusting valve 7 for adjusting the flow rate of the gas is provided.

  The furnace floor 3 is provided with a plurality of suction ports 8 and a flue 9 communicating with the suction ports 8. The flue 9 extends outward from the furnace, and the extended portion is connected to the furnace body 1. It communicates with the chimney 10 installed outside. A pressure adjusting valve 11 for adjusting the pressure in the furnace is provided at the connection portion between the chimney 9 and the chimney 10, and an exhaust gas flow rate adjusting valve 12 for adjusting the flow rate of the exhaust gas is provided in the middle of the passage of the chimney 10.

  An inorganic heat insulating packing is applied to the opening / closing portion of the door and other connection portions, and the entire furnace is configured to have an airtight structure.

Next, an example of performing the carburizing process using the furnace configured as described above will be described.
Open the furnace door, place a plurality of fired products 13 (ceramic sintered bodies formed in a container shape) on each stage of the shelf 2, then close the door, open the open / close valve of the LP gas cylinder 6, The gas is sent to the gas burner 4 in the furnace through the gas supply pipe 5 and burned. For gas combustion, LP gas is supplied into the furnace in the presence of oxygen. That is, LP gas is supplied into the furnace together with air. At this time, the mixing ratio of LP gas and air is adjusted by the supply gas flow rate adjusting valve 7. The furnace and the fired product 13 are heated by this gas combustion. The combustion gas is guided from the suction port 8 to the flue 9, enters the chimney 10, and is discharged from the chimney 10 into the atmosphere.

  When the temperature of the furnace and the fired product 13 rises to 1000 ° C. to 1100 ° C., the supply gas flow rate adjusting valve 7 is operated to stop the air supply and stop the gas combustion. In this state, LP gas is supplied into the furnace, and the opening degree of the pressure regulating valve 11 and the exhaust gas flow rate regulating valve 12 is adjusted so that the pressure in the furnace becomes larger than the external pressure. Such pressure adjustment can prevent air from entering the furnace. The LP gas supplied into the furnace contacts the fired product 13 in the absence of oxygen.

  Under this high temperature and reducing atmosphere, LP gas is heated, and hydrocarbons such as propane and butane, which are main components of LP gas, are thermally decomposed. Carbon isolated from the hydrocarbon pyrolysis gas adheres to and accumulates on the surface of the fired product 13 and the pores of the porous structure of the ceramic sintered body that is the material of the fired product 13. Thus, carbon is vapor-deposited on the surface and pores of the fired product 13 by a gas phase reaction, and a carbon thin film layer is formed.

  When the furnace is naturally cooled and the furnace temperature becomes equal to or lower than the ignition and combustion temperature of carbon, the furnace door is opened, and the carburized fired product 13 is taken out of the furnace. The step of opening the furnace door and introducing outside air is preferably performed when the furnace temperature is cooled to 350 ° C. or lower.

  The fired product 13 that has been carburized as described above is used as a heating tool for a microwave oven of the present invention. The heating tool of the present invention thus obtained exhibits a black appearance due to carbon.

  Since the heating device for a microwave oven of the present invention has a carbon thin film layer formed on the surface of the ceramic sintered body and in the pores, the food to be cooked such as food and drink is put in the heating device of the present invention, When heated in the microwave oven, the carbon thin film layer absorbs microwaves generated from the magnetron of the microwave oven and generates heat, whereby the heating tool of the present invention is heated in the microwave oven.

  As a result, not only the food to be cooked is heated by the microwave, but also the heating device of the present invention is heated by the microwave itself, so that the food to be cooked can be sufficiently heated and the food to be cooked even after taking out from the microwave Has the effect of keeping warm.

  According to the present invention, a carbon thin film layer can be formed in pores at selected sites in a ceramic sintered body. That is, the present invention is not limited to the formation of the carbon thin film layer in all the pores in the porous structure of the ceramic sintered body, and the carbon thin film layer is formed only in the pores in a selected portion of the pores. It may be.

  In forming such a so-called partial carbon thin film layer, partial masking may be performed using a material difficult to permeate carbon, and the partially masked ceramic sintered body may be carburized. As the masking material used in this case, a general glaze applied to the surface of the ceramic can be used, and it is particularly preferable to use a glaze that forms a vitreous layer.

  In the partial masking with the glaze, the selected portion is made free of glaze, and the glaze is applied to other portions. When this partially masked ceramic sintered body is subjected to carburizing treatment, carbon is deposited on the surface and pores of the ceramic sintered body in the solid portion to form a carbon thin film layer. On the other hand, in the portion where the glaze has been applied (glazed portion), carbon is deposited on the surface of the glaze, but carbon does not permeate through this glaze layer, so in the ceramic sintered body covered with the glaze layer, No carbon is deposited on the surface, so that the carbon thin film layer is formed only on the surface of the glaze layer and not in the pores.

  In this way, the carbon thin film layer is formed on the surface and pores in the solid part, while the carbon thin film layer is formed only on the surface in the glazed part, so there is no calorific value during microwave heating. It is larger in the heel than in the glazed part. Here, when the portion corresponding to the flangeless portion is referred to as a high heat generation portion and the portion corresponding to the glazed portion is referred to as a low heat generation portion, according to this embodiment of the present invention, a part of the heating device for the microwave oven according to the present invention is used. It can be configured as a high heat generating part, and the other part can be configured as a low heat generating part.

  As a specific aspect in this embodiment, when the ceramic sintered body has a bowl shape such as a tea cup, for example, the upper part of the bowl can be configured as a low heat generation part, and the lower part can be configured as a high heat generation part. In this case, even if a drink is placed in a bowl and heated with an electronic lens, the amount of heat generated at the top of the bowl is small.

  Also, in the case of a container with a handle, if the handle part is configured as a low heat generation part, the heat generation amount of the handle part is small, so when taking out the container from the microwave oven, it is too hot to hold the handle part in the same way There is no.

  Furthermore, if a high heat generating part is formed at a specific position above the container, it is possible to burn the upper part of the food as the contents.

  In general, when a liquid such as milk is placed in a deep bottom container and heated in a microwave oven, the heating temperature is lower in the lower part than in the upper part of the liquid, and a temperature gradient is generated along the depth. According to the above embodiment of the present invention, the upper part of the deep bottom container can be configured as a low heat generating part, and the lower part of the container can be configured as a high heat generating part. Can be heated uniformly in the vertical direction.

  In a ceramic container with glaze, it is normal that no glaze is applied to the bottom of the container, and when this container is carburized, the pores constituting the porous structure at the bottom of the container, which is an unglazed part Carbon is deposited inside, and a carbon thin film layer is formed.

  When the food to be cooked is put in the heating tool of the present invention in this embodiment and heated in the microwave, the carbon thin film layer at the bottom of the container becomes a heat generating part, the container generates heat, and the cooking object is heated, and the microwave oven is heated. Demonstrate heat retention after heating.

  The heating tool of the present invention can be applied to tableware such as bowls, bowls, cups of hot water, dishes, bowls and the like, pots such as teapots and bottles, cooking utensils such as earthenware pots and ceramic plates, hot plates, and heat insulation containers.

Examples of the present invention will be described below.
Example 1
Ceramic base material composition Petalite powder 50 parts by weight Plastic clay 20 parts by weight Alumina 10 parts by weight Amakusa porcelain clay 20 parts by weight The components of the ceramic base material having the above composition are mixed in a wet manner, dehydrated, and then adjusted to mud. Then, a plate-like piece having a length of 90 mm × width of 90 mm × thickness of 30 mm was formed by casting, dried, and then baked at 800 ° C. The obtained unglazed piece was fired at 1250 ° C. for 12 hours in the air to obtain a sintered piece. The water absorption of the sintered piece was measured and found to be 3.2% by weight.

The sintered piece was placed in the furnace shown in FIG. 2, and LP gas was blown into the furnace to be heated to a temperature of 1100 ° C. and carburized for 10 hours. As a result, a test piece exhibiting a uniform black color was obtained. This test piece was put in a household microwave oven (output 600 W), and the heat generation temperature when microwaves were irradiated for 30 seconds, 60 seconds, and 90 seconds, respectively, was measured with a surface thermometer (905-T2 type manufactured by Testo). That is, the first test piece is first taken out of the microwave oven after 30 seconds of heating, the surface thermometer is applied to the test piece to measure the heat generation temperature, and then the second test piece is heated after 60 seconds of heating. The test piece was taken out of the range and the exothermic temperature was measured in the same manner, and the third test piece was taken out after heating for 90 seconds, and the exothermic temperature was measured. The results are shown in Table 1.
Example 2
A sintered piece is made in the same manner as in Example 1 using the ceramic substrate shown in Example 1, and a glaze is applied to a region from one side of this sintered piece to a point having a length of 60 mm to form a glazed portion. . As the glaze, 50 parts by weight of petalite powder, 5 parts by weight of plastic clay, 30 parts by weight of feldspar, and 15 parts by weight of talc were pulverized and mixed in a wet manner to adjust the moisture content to 45 parts by weight. The water absorption of the glazed sintered piece was measured and found to be 2.5% by weight.

Next, the sintered piece was subjected to carburizing treatment in the same manner as in Example 1. A test piece in which the glazed portion was cream-colored and the unglazed portion was black was obtained. The heat generation temperature of this test piece was measured in the same manner as in Example 1. The exothermic temperature was measured by applying a surface thermometer to the solid part. The results are shown in Table 1.
Comparative Example 1
Using the ceramic substrate shown in Example 1, the same sintered piece was produced in the same manner as in Example 1. The sintered piece was not subjected to carburization treatment as a test piece, and the heat generation temperature of this test piece was measured in the same manner as in Example 1. The results are shown in Table 1.
Comparative Example 2
Using the ceramic base material shown in Example 1, the same sintered piece having a glazed part and an unglazed part was produced in the same manner as in Example 2. The sintered piece that was not carburized was used as a test piece, and the exothermic temperature of this test piece was measured in the same manner as in Example 1 (the measurement location was a solid part). The results are shown in Table 1.

(Table 1)

From the measurement results, it can be seen that Examples 1 and 2 generate heat at a high temperature, but Comparative Examples 1 and 2 hardly generate heat. In Example 1, the rate of increase in the heat generation temperature is larger than that in Example 2, and the heat is generated at a higher temperature.
Example 3
A container shown in FIG. 3 is formed by casting using the ceramic substrate shown in Example 1, and subjected to unglaring by the same method as in Example 1, and then fired to obtain a container having the same water absorption rate as in Example 1. Produced. This container was carburized by the same method as in Example 1.

The carburized container is put into a microwave oven in the same manner as in Example 1, heated by irradiation for 60 seconds, then taken out, and the same surface thermometer as used in Example 1 is applied to each part of the container. The exothermic temperature at each site was measured. Exothermic temperature was measured about each part of mouth edge part 14, body part 15, and hill 16 of a container. The results are shown in Table 2.
Example 4
A container was manufactured in the same manner as in Example 3 using the ceramic substrate shown in Example 1. When the height from the mouth edge 14 of the container to the hill 16 is L, glaze is applied to the region having a length corresponding to 2L / 3 from the mouth edge 14 to the hill 16 by the same method as in the second embodiment. A glazed glazed portion was formed, and a carburizing treatment was performed on the container formed with the glazed portion in the same manner as in Example 1.

The carburized container was heated in the microwave by the same method as in Example 1, and the exothermic temperature at each part of the container was measured as in Example 3. The results are shown in Table 2.
Comparative Example 3
A container was manufactured in the same manner as in Example 3 using the ceramic substrate shown in Example 1. Without subjecting this container to carburizing treatment, it was heated in a microwave oven in the same manner as in Example 1, and the exothermic temperature at each part of the container was measured as in Example 3. The results are shown in Table 2.

(Table 2)

  From the measurement results, it can be seen that in Examples 3 and 4, a high heat generation temperature is obtained in each part, but in the case of Comparative Example 3, almost no part generates heat. Among Examples 3 and 4, Example 3 can obtain a substantially uniform heat generation temperature at each part. However, in Example 4, the heat generation temperature gradually increases from the lip 14 to the hill 16 and causes a temperature gradient. Yes.

  The microwave oven heater of the present invention is easy to manufacture, can exhibit sufficient strength, is excellent in heat generation and heat retention performance, and is extremely useful for use as a cooking utensil for foods and drinks.

It is a cross-sectional photograph of the ceramic sintered compact by a scanning electron microscope. It is explanatory drawing for demonstrating a carburizing process. It is the cross-sectional schematic of the container which shows the site | part which measures exothermic temperature.

Explanation of symbols

A. Pores of ceramic sintered body B Surface of ceramic sintered body 14 Mouth part 15 Body part 16 Height

Claims (6)

  A heating device for a microwave oven comprising a ceramic sintered body, wherein a carbon thin film layer is formed on the surface and pores of the ceramic sintered body by carburizing treatment.   The heating device for a microwave oven according to claim 1, wherein the carbon thin film layer is made of carbon obtained by thermal decomposition of hydrocarbon.   The carbon thin film layer formed by carburization is formed by heating the ceramic sintered body, introducing LP gas, heat-treating in a reducing atmosphere, and depositing carbon on the surface and pores of the ceramic sintered body by a gas phase reaction. The heating device for a microwave oven according to claim 1, wherein the heating device is a microwave oven.   The heating device for a microwave oven according to claim 1, wherein a carbon thin film layer is formed in pores at selected portions of the ceramic sintered body.   5. The electron according to claim 4, wherein the selected portion is made a solid part, and a carburizing treatment is performed by applying glaze to the other part, and a carbon thin film layer is formed in the pores of the ceramic sintered body in the solid part. Heating tool for the range.   The heating tool for a microwave oven according to claim 1, which is formed into a container shape.