TWI816975B - Firing jig - Google Patents

Abstract

An object of the present invention is to provide a firing jig that has low reactivity with electronic component materials and active material materials of lithium batteries. The solution of the present invention is a firing jig, which has a SiC or Si-SiC base material and a coating layer covering the surface of the base material. The coating layer includes a first layer that is provided on the surface of the base material and contains Al ₂ O ₃ —SiO ₂ as a main component, and a second layer that is exposed on the surface of the coating layer. When used as an electronic component material, the second layer contains at least one selected from Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo as the main component. When used as an active material material for lithium batteries, the second layer contains At least one selected from Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO is used as the main component.

Description

Firing jig

This specification discloses techniques for firing jigs. In particular, a technology related to a firing jig used for firing electronic component materials or firing active material materials that can be used in lithium batteries is disclosed.

Patent Document 1 discloses a firing jig as a firing jig for ceramics for electronic components. A second layer of Al ₂ O ₃ -SiO ₂ is formed on the surface of a SiC substrate (first layer). The third layer of 8Y-ZrO ₂ (8wt%Y ₂ O ₃ -ZrO ₂ ) is formed on the surface. The third layer is provided to prevent the object to be fired (ceramics for electronic components) from reacting with the firing jig. Furthermore, the second layer is provided to prevent the third layer from peeling off from the SiC substrate (first layer). More specifically, the second layer prevents oxygen passing through the third layer from reaching the SiC substrate, thereby suppressing surface oxidation of the SiC substrate. In addition, if the surface of the SiC substrate is oxidized, the third layer will be peeled off from the firing jig. Furthermore, Patent Document 1 lists Al ₂ O 3 , Al ₂ O ₃ -SiO ₂ -MgO, and _{MgO -} Al as materials that can be used for the second layer in addition to Al ₂ O ₃ -SiO 2. ₂ O ₃ -ZrO ₂ quality. In addition, in addition to 8Y-ZrO ₂ , materials that can be used for the third layer include Al ₂ O ₃ , mullite, ZrO ₂ , and Y ₂ O. [Prior art documents] [Patent documents]

[Patent Document 1] Japanese Patent Application Publication No. 2003-306392

[Problem to be solved by the invention]

In general, _ZrO2 is known as a material with low reactivity (hardly reactive material). Therefore, as long as ZrO ₂ is formed on the outermost surface layer (top coat layer) of the firing jig, the reaction between electronic components (or raw materials for electronic components) and the constituent materials of the firing jig can be suppressed to a certain extent. Patent Document 1 also uses ZrO ₂ and other materials for the third layer (top coating) to suppress the reaction between the electronic components and the firing jig. On this premise, the third layer is removed from the firing jig. Think about countermeasures when it comes to stripping. However, even if the above-mentioned materials are used as the top coating, it is not possible to completely prevent the electronic component materials (electronic components and their raw materials) from reacting with the firing jig. Therefore, in order to improve the manufacturing yield of electronic component materials, there is a demand for a firing jig that further reduces reactivity with electronic components and the like. The purpose of this specification is to provide a novel firing jig that has lower reactivity with electronic components (electronic component materials, active material materials of lithium batteries). [Means used to solve problems]

One form of the firing jig disclosed in this specification is used for firing electronic component materials. The firing jig may have a SiC or Si-SiC base material and a covering layer covering the surface of the base material. Moreover, the coating layer may include: a first layer provided on the surface of the base material and containing Al ₂ O ₃ -SiO ₂ as a main component; and a second layer exposed on the surface of the coating layer and selected from Y At least one of ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo serves as the main component.

Another form of the firing jig disclosed in this specification is used for firing active materials of lithium batteries. The firing jig may have a SiC or Si-SiC base material and a covering layer covering the surface of the base material. Moreover, the coating layer may include: a first layer provided on the surface of the base material and containing Al ₂ O ₃ -SiO ₂ as a main component; and a second layer exposed on the surface of the coating layer and selected from Y At least one of ₂ O ₃ , HfO ₂ , CeO ₂ and NiO serves as the main component.

(Firing Jig) This specification discloses a firing jig used for firing electronic component materials such as ceramic capacitors containing barium titanate (BaTiO ₃ ) as a main component and raw materials of the ceramic capacitors. Furthermore, this specification also discloses a firing jig for firing active material materials such as active materials of lithium batteries containing lithium cobalt oxide (LiCoO ₂ ) as a main component and raw materials of the active materials. Both firing jigs may have a common feature, which is a so-called base material made of SiC or Si-SiC, and a coating layer covering the surface of the base material. The thickness of the base material can be 0.4 to 5 mm. If it is within this range, the heat capacity of the base material can be controlled, and electronic component materials or active material materials of lithium batteries can be fired efficiently. In addition, in both firing jigs, the coating layer may have a common feature, which is that it includes a first layer that is provided on the surface of the base material and contains Al ₂ O ₃ -SiO ₂ as a main component. ; and a second layer, which is exposed on the surface of the covering layer. In the electronic component material, the second layer may have at least one selected from the group consisting of Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo as a main component. Furthermore, among the active material materials, the second layer may contain at least one selected from the group consisting of Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO as a main component.

In addition, "electronic component materials" include, for example, not only electronic component molded bodies such as ceramic capacitors, but also raw materials (intermediates) used to form the molded bodies. Similarly, the so-called "active material" includes not only the active material of the lithium battery itself, but also the raw materials (intermediates) used to form the active material. Furthermore, the term "the first layer contains Al ₂ O ₃ -SiO ₂ as a main component" means that the Al ₂ O ₃ -SiO ₂ substance accounts for more than 50% by mass of the raw materials (compounds) constituting the first layer. For example, the first layer may contain less than 50% by mass of Al ₂ O ₃ material in addition to Al ₂ O ₃ -SiO ₂ material. In addition, the first layer may contain 70% by mass or more of Al ₂ O ₃ -SiO ₂ , may contain 80% by mass or more, may contain 90% by mass or more, or may contain only Al ₂ O ₃ -SiO ₂ ( sometimes contain unavoidable impurities).

Similarly, the "main component" of the second layer means a raw material (component) accounting for more than 50% by mass of the raw material (compound) constituting the second layer. For example, when the second layer contains Y ₂ O ₃ as the main component, the mass of Y ₂ O ₃ is 50% or more of the total mass of the second layer. Furthermore, when the second layer contains Y ₂ O ₃ and HfO ₂ as main components, the total mass of Y ₂ O ₃ and HfO ₂ is 50% or more of the total mass of the second layer. In addition, it is preferable that the second layer contains any one of Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo as a main component in the electronic component material, and the active material material preferably contains Any one of Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO serves as the main component. The second layer may contain the above-mentioned raw materials (compounds) individually or in combination at 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or it may consist essentially of only It is composed of the above raw materials (sometimes including unavoidable impurities).

The material of the second layer (top coating) of the above-mentioned firing jig is different from those used in the past. The material cited as the second layer for electronic component materials is calculated by calculating the thermodynamic equilibrium state (simulation) of a multi-component system in a high-temperature environment for barium titanate (BaTiO ₃ ), which is commonly used as a material for electronic components. Materials for obtaining low reactivity results. In addition, while Al ₂ O ₃ , ZrO _{2 ,} etc., which have been conventionally used as top coats, BaTiO ₃ has been found to easily generate reaction products in a high-temperature environment when calculating the thermodynamic equilibrium state of a multi-component system. In addition, the materials cited as the second layer for active material materials are the materials cited as the second layer for electronic component materials (Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni , Mo), we actually made samples and conducted experiments on oxides (Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO), and obtained good results for lithium cobalt oxide (LiCoO ₂ ) used as general active material materials. Result material.

The material cited as the second layer has lower reactivity with BaTiO ₃ and LiCoO ₂ than the materials used as the top coat in the past. As mentioned above, if Al ₂ O ₃ , ZrO ₂ , etc. are used as the top coating of conventional firing jigs, the reaction between the object to be fired and the firing jigs can be suppressed, and on this premise, the durability of the covering layer can be improved. improvement. However, even if the durability of the coating layer is improved, if the object to be fired reacts with the covering layer (top coat), the production yield of the object to be fired will not be improved. In order to focus on reducing the reactivity of the top coating itself with respect to the object to be fired (electronic component material), the above-mentioned firing jig is realized using a completely different technical idea from the conventional ones.

In the firing jig for electronic component materials, the second layer may have at least one selected from the group consisting of Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO as a main component. Because these materials are oxides, they are chemically stable and easy to handle. In addition, as mentioned above, these materials have been experimentally confirmed to obtain good results (low reactivity) with LiCoO ₂ . The firing jig for electronic component materials can be directly used as a firing jig for electronic components.

In the above-mentioned firing jig, the base material, the first layer, and the second layer may be selected so that the thermal expansion coefficient of the first layer is equal to or greater than the thermal expansion coefficient of the base material, and the thermal expansion coefficient of the second layer is equal to or greater than the thermal expansion coefficient of the first layer. s material. The thermal expansion coefficient of the base material (SiC or Si-SiC) used in the above-mentioned firing jig is approximately 4 (ppm/k). On the other hand, the thermal expansion coefficients of the materials cited as the second layer are all 4 (ppm/k) or more. By setting the thermal expansion coefficient of the first layer to be equal to or greater than the thermal expansion coefficient of the base material, and setting the thermal expansion coefficient of the second layer to be equal to or greater than the thermal expansion coefficient of the first layer, the difference in thermal expansion coefficient between the base material and the second layer can be alleviated, thereby suppressing The cover layer peels off the substrate.

In the above-mentioned firing jig, a third layer containing Al ₂ O ₃ as a main component may be provided between the first layer and the second layer. In addition, "the third layer contains Al ₂ O ₃ as a main component" means that the third layer contains 50 mass % or more of Al ₂ O ₃ . By providing the third layer, the first layer and the second layer can be joined more strongly and firmly, and peeling of the first layer and the second layer can be suppressed. In addition, mutual diffusion of the constituent elements of the first layer (or base material) and the second layer can also be suppressed. The thickness of the third layer can be 10 to 200 μm, or less than 50% of the overall thickness of the covering layer. In addition, the third layer may contain Al ₂ O ₃ in an amount of 60 mass % or more, 70 mass % or more, 80 mass % or more, 90 mass % or more, or it may consist essentially of only Al _{2 O 3} . Made of O ₃ matter. In addition, when the first layer and the second layer are directly connected (that is, when the third layer is not provided), a structure whose composition gradually changes between the first layer and the second layer can also be provided. Inclined layer. Similarly, when a third layer is provided between the first layer and the second layer, an inclined layer may also be provided between the first layer and the third layer, and/or between the third layer and the second layer. Furthermore, a plurality of layers may be provided between the first layer and the second layer.

In the above-mentioned firing jig, a plurality of flat particles may be present in the second layer, and the plurality of flat particles are formed by melting and solidifying the particles constituting the second layer. The flat particles may be obtained by melting and solidifying the particles constituting the second layer when the second layer is fired (sintered). The flat particles can be laminated in the direction in which the base material, the first layer and the second layer are laminated. That is, the flat particles can be stacked in the thickness direction of the covering layer. In addition, the number of laminates of flat particles is not particularly limited as long as it is 2 or more. By the presence of flat particles in the second layer, the difference in thermal expansion between the base material and the second layer is alleviated, thereby suppressing peeling of the second layer. As described above, the thermal expansion coefficient of the material constituting the second layer may be greater than or equal to the thermal expansion coefficient of the base material (SiC or Si-SiC). In this case, when the jig is heated and fired, the base material exerts a compressive force on the second layer, or the second layer exerts a tensile force on the base material. If the flat particles are laminated in the second layer, the force exerted on the second layer (applied by the second layer) during heating is relaxed, thereby suppressing the peeling of the coating layer due to the difference in thermal expansion coefficient.

In addition, the flattening ratio ((short side direction length/long side direction length)×100) of the flat particles may be 95% or less. Furthermore, as long as the flatness ratio of the flat particles is 95% or less, the strength of the flat particles themselves is ensured, and as a result, the strength of the second layer is ensured. In addition, the flat particles may have a flat shape or a curved shape. In particular, when the flat particles have a curved shape, the effect of alleviating the difference in thermal expansion between the base material and the second layer can be easily obtained. Flat grains can exist entirely in the second layer or partially. Even in the case where the flat particles are partially present in the second layer, the above-mentioned alleviation effect of the thermal expansion difference can be obtained. In addition, the flatness ratio of the flat particles can be calculated by measuring the longitudinal (long side direction) and transverse (short side direction) lengths of the particles from an SEM image of the cross section of the coating layer (for example, 1000 times), and using the above calculation formula.

In the above-mentioned firing jig, the thickness of the covering layer may be 20 to 600 μm. Also, the first layer may be thicker than the second layer. Specifically, the thickness of the first layer may be 50-500 μm, and the thickness of the second layer may be 5-500 μm. As long as the thickness of the first layer is 50 μm or more, the reaction with the object to be fired can be suppressed, and the strength of the coating layer can be maintained, thereby further suppressing peeling of the coating layer. As long as the thickness of the first layer is 500 μm or less, the reaction with the object to be fired can be suppressed, and at the same time, the strength of the coating layer is more stable, and the peeling of the coating layer can be further suppressed. As long as the thickness of the second layer is 5 μm or more, the second layer is reliably formed on the entire surface of the substrate, and the reaction between the object to be fired and the firing jig can be sufficiently suppressed. As long as the thickness of the second layer is 500 μm or less, the second layer itself is suppressed from delaminating, and as a result, the second layer is suppressed from being delaminated from the base material (first layer). In addition, the thickness of the second layer may be 10 μm or more, or may be 50 μm or more. Moreover, the thickness of the second layer may be 200 μm or less, 150 μm or less, or 100 μm or less. In addition, the second layer is a layer exposed on the surface of the covering layer, and may also be a so-called top coat layer.

In the above-mentioned firing jig, the void ratio (porosity) of the covering layer (first layer, second layer) may be 10 to 60 volume %. As long as the void ratio is 10% by volume or more, the reaction with the object to be fired can be suppressed, and at the same time, the strength of the coating layer is more stable, and the peeling of the coating layer can be further suppressed. As long as the void ratio is 60 volume % or less, the reaction with the object to be fired can be suppressed, and the strength of the coating layer can be maintained, thereby further suppressing the peeling of the coating layer. In addition, the thermal conductivity of the covering layer may be 2 to 250W/(m·k). As long as the thermal conductivity of the coating layer is 2 to 250W/(m·k), when the object is fired, the temperature within the surface of the object can be made uniform. More preferably, the thermal conductivity of the covering layer is 3 to 30 W/(m·k). In addition, the porosity (porosity) can be used to trim the SEM image of the cross-section of the covering layer (for example, 1000 times) to create a unique image of each layer (first layer, second layer, etc.), using image processing software (ImageNos version 1.04: free software), which distinguishes gaps from other parts by binarization, and calculates the area ratio of the gaps relative to the whole.

(Firing jig for electronic component materials) As mentioned above, in the sintering jig for firing electronic component materials, the second layer can be selected from the group consisting of Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni , at least one of them is used as the main component. As shown in Figure 1, the thermodynamic equilibrium state of Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo for BaTiO ₃ using thermodynamic equilibrium calculation software (FactSage: GTT-Technologies, manufactured by Thermfact Ltd.) In the calculation, it was confirmed that it does not react with BaTiO ₃ (no reaction product is formed). On the other hand, ZrO ₂ , Al ₂ O ₃ , and TiO ₂ , which have been conventionally considered useful as the second layer (top coat layer), have been confirmed to react with BaTiO ₃ to produce a reaction product (Ba compound). In addition, as shown in Figure 1, although HfO ₂ does not react with BaTiO ₃ , it was confirmed that Hf reacts with BaTiO ₃ to produce a reaction product (BaHfO ₃ ). In other words, it was confirmed that it is not that compounds (or monomers) containing elements such as Y, Hf, Ce, Ni, etc. do not react with BaTiO ₃ but that it is due to the form of the above-mentioned oxides (HfO ₂ , Y ₂ O ₃ , CeO ₂ , NiO) will not react with BaTiO ₃ .

Figure 1 also shows the calculation results of the thermodynamic equilibrium state of BaTiO ₃ for SiC, which is an example of the substrate material, and Al ₂ O ₃ ·SiO ₂ , which is an example of the first layer material. It was confirmed that SiC, Al ₂ O ₃ and SiO ₂ reacted with BaTiO ₃ to form a reaction product. In addition, FIG. 1 also shows the thermal expansion coefficients of each material of the second layer, SiC, and Al ₂ O ₃ ·SiO ₂ . In such a manner that the thermal expansion coefficient of each layer does not become smaller from the base material toward the surface of the covering layer, that is, the thermal expansion coefficient of the first layer is equal to or greater than the thermal expansion coefficient of the base material and the thermal expansion coefficient of the second layer is equal to or greater than the thermal expansion coefficient of the first layer By selecting the materials of the base material, the first layer and the second layer in such a way that the coefficient of thermal expansion is above [Example]

As mentioned above, in the firing jig for electronic component materials, if Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo are used as the second layer, the electronic component material and the sintering jig ( second layer) to react. Next, samples were prepared to form the second layer (top coat) using Y ₂ O ₃ , HfO ₂ , CeO ₂ , and NiO among the above materials, and the characteristics of each sample with respect to BaTiO ₃ and LiCoO ₂ were evaluated (samples 1 to 20). . For comparison, samples in which the second layer was formed using ZrO ₂ (samples 21 to 24) were also produced, and the characteristics were evaluated together. The evaluation results are shown in Figure 2.

First, the preparation method of the sample will be explained. A Si-SiC plate and a SiC sintered body plate (substrate) with a length and width of 150 mm x 150 mm and a thickness of 2 mm are prepared, and the first layer of mullite (Al ₂ O ₃ -SiO ₂ material) is formed on the surface of the substrate using the spray method. In samples 3, 6, 13, 22, and 24, SiC sintered body plates were used as substrates, and other samples used Si-SiC plates as substrates. In addition, the thickness of the first layer was set to 50 μm for samples 2, 3, 10, 21, and 22, and was set to 100 μm for the other samples. Next, each sample was fired at 1350° C. for 2 hours in an atmospheric gas environment. After that, a thermal spraying method is used to form a second layer on the surface of the first layer with the material and thickness shown in Figure 2. A reaction test and a peeling test were performed on the obtained samples 1 to 24. In addition, separate samples were used for the reaction test and peeling test. In addition, regarding sample 5, a SEM (scanning electron microscope: JSM-5600 manufactured by JEOL Ltd.) was used to observe the coating layer at a magnification of 300 times. The SEM photo is shown in Figure 3.

(SEM observation) As shown in FIG. 3 , the second layer is composed of a plurality of flat grains, and it is confirmed that each flat grain is laminated in the thickness direction. It was also confirmed that each flat grain was not flat, but had an irregular curved shape, and gaps were provided between the flat grains. This gap is thought to moderate the thermal expansion of the second layer (the flat grains that make up the second layer).

(Reaction test) A reaction test is performed on each sample. The reaction test is a 35-cycle test on a sample in which 10 g of the object to be burned (BaTiO ₃ , LiCoO ₂ ) and BaTiO ₃ are placed in the center part of the sample surface. The test is carried out at 1200 in an atmospheric gas environment. The process of baking at ℃ for 1 hour and then cooling to room temperature is regarded as one cycle. In addition, a 35-cycle test was performed on the sample on which LiCoO ₂ was mounted. In this test, one cycle was defined as a process of firing at 1000° C. for 1 hour in an atmospheric gas environment and then cooling to room temperature. In addition, at the start of each cycle, the materials to be burned (BaTiO ₃ , LiCoO ₂ ) are replaced with new ones. Therefore, in the reaction test, a total of 350 g of the burned material was fired.

For each sample after the reaction test, the permeability of the sample and the adhesion of the coating layer to the constituent elements (Ba, Ti, Li, Co) of the fired object were evaluated. The permeability system uses an EDS (energy dispersive X-ray spectrometer) installed in the SEM to map Ba, Ti, Li, and Co elements to measure the penetration depth of the constituent elements of the fired object from the surface layer of the coating layer. and evaluate. It shows that the deeper the penetration depth from the surface layer is, the more the fired object reacts with the sample (equivalent to the firing jig). Samples with a penetration depth of 10 μm or less from the surface layer of the above-mentioned constituent elements are designated as "A", samples with a penetration depth of greater than 10 μm and less than 20 μm from the surface layer are designated as "B", and samples with a penetration depth of greater than 20 μm and less than 30 μm from the surface layer are designated as "B". is "C", and samples with a penetration depth greater than 30 μm from the surface layer are set as "D". Evaluations "A" and "B" indicate that the reaction-inhibiting effect between the fired object and the sample is high (especially "A" is good), evaluation "C" indicates that the reaction-inhibiting effect is slightly poor, and evaluation "D" indicates that the reaction-inhibiting effect is low . The evaluation results are shown in Figure 2.

Regarding the adhesion, when the fired objects are exchanged (after completion of one cycle), the peeling of the coating layer is visually confirmed and evaluated. The sample in which peeling was not confirmed after 30 cycles was designated as "A", the sample in which peeling was confirmed between 21 and 30 cycles was designated as "B", and the sample in which peeling was confirmed between 11 and 20 cycles was designated as "B". is "C", and the sample in which peeling was confirmed between 1 to 10 cycles is "D". The evaluation results are shown in Figure 2.

(Peel test) A peel test was performed on each sample. The peeling test is performed by preparing a different sample from the reaction test. The peeling test was a 6-cycle test performed on each sample. In this test, one cycle consisted of firing at 1350° C. for 2 hours and then cooling to room temperature in an atmospheric gas environment. After each cycle, a 10 mm × 15 mm gum tape (manufactured by KIKUSUI TAPE Co., Ltd., cloth tape No. 212; 50 mm 25M) was attached to the surface of each sample, and the tape was peeled off to visually confirm whether there was a covering layer. Peel and evaluate. In addition, tape is attached to the central part of the specimen. In order to attach the tape to the sample (covering layer), after the tape was attached to the sample, a weight of 2 kg was placed on the tape for 10 seconds. The sample in which peeling was not confirmed after 6 cycles was designated as "A", the sample in which peeling was confirmed after 4 or 5 cycles was designated as "B", and the sample in which peeling was confirmed after 2 or 3 cycles was designated as "B". is "C", and the sample in which peeling was confirmed after completion of one cycle is "D". The evaluation results are shown in Figure 2.

(Judgment of usefulness) Based on the results of the above reaction test and peeling test, samples with 3 or more evaluations "A" will be judged as "A", samples with 1 or 2 evaluations "A" and no evaluation "C" and samples with evaluation "D" will be considered as judgment "A". Let it be judged "B", and let the sample without any evaluation "A" be judged "C". The samples (baking jigs) judged as "A" and "B" have low reactivity with electronic component materials and active material materials used in lithium batteries, indicating that they are useful as baking jigs. In particular, the sample (firing jig) rated "A" can be said to have excellent characteristics as a sintering jig for electronic component materials and active material materials used in lithium batteries.

As shown in Figure 2, compared to the samples (samples 21 to 24) in which the second layer was formed using ZrO ₂ , the second layer was formed using Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo. samples (samples 1 to 20) were confirmed to exhibit excellent characteristics (for example, comparative samples 5, 12, 18, 19, 20, and 23). In addition, the same effect was confirmed for both the Si-SiC plate and the SiC sintered body plate (compare samples 2 and 3, samples 5 and 6, samples 12 and 13, samples 21 and 22, and samples 23 and 24) . In addition, in the samples (samples 1 to 15) in which the second layer was formed using Y ₂ O ₃ and HfO ₂ , it was confirmed that good results were obtained when the thickness of the second layer was changed to 10 μm to 200 μm. In particular, the samples with a thickness of 50 to 150 μm (samples 2 to 7, and samples 10 to 14) showed good results. In addition, similarly to the samples in which the second layer was formed using Y ₂ O ₃ and HfO ₂ (samples 5 and 12), the samples in which the second layer was formed using CeO ₂ , NiO, WC, Ni, and Mo (samples 16 to 21 ) was confirmed to exhibit excellent characteristics.

Although specific examples of the present invention have been described in detail above, these are only examples and do not limit the scope of the patent application. The technology described in the claimed scope includes various modifications and changes to the specific examples illustrated above. In addition, the technical elements described in the present invention or the drawings exert technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. In addition, the technology illustrated in the present invention or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objectives itself.

without.

[Figure 1] shows the calculation results of reaction products in the thermodynamic equilibrium state of BaTiO ₃ in a multi-component system. [Fig. 2] shows the results of the experimental example. [Fig. 3] SEM photograph showing the coating layer.

Claims (6)

A firing jig used for firing ceramic capacitors containing barium titanate as a main component and electronic component materials that are raw materials of the ceramic capacitors, and having a base material of SiC or Si-SiC. , and a covering layer covering the surface of the base material, the covering layer includes: a first layer, which is provided on the surface of the base material and has Al ₂ O ₃ -SiO ₂ as the main component; and a second layer, which is on the surface of the covering layer The surface layer is exposed, and has at least one selected from Y ₂ O ₃ , HfO ₂ , CeO ₂ , NiO, WC, Ni, and Mo as the main component. A firing jig used for firing active material materials such as active materials of lithium batteries containing lithium cobalt oxide as a main component and raw materials of the active materials, and is provided with SiC or Si-SiC The base material is a base material, and the covering layer covers the surface of the base material. The covering layer includes: a first layer, which is provided on the surface of the base material and has Al ₂ O ₃ -SiO ₂ as a main component; and a second layer, which is The surface layer of the covering layer is exposed, and at least one selected from Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO is used as the main component. Such as the firing jig of claim 1, wherein the second layer has at least one selected from the group consisting of Y ₂ O ₃ , HfO ₂ , CeO ₂ and NiO as the main component. The firing jig according to any one of claims 1 to 3, wherein the thermal expansion coefficient of the first layer is equal to or greater than the thermal expansion coefficient of the base material, and the thermal expansion coefficient of the second layer is equal to or greater than the thermal expansion coefficient of the first layer. Base material, first layer and second layer materials. The firing jig according to any one of claims 1 to 3, wherein a third layer containing Al ₂ O ₃ as a main component is provided between the first layer and the second layer. The firing jig according to any one of claims 1 to 3, wherein there are a plurality of flat particles in the second layer, and the plurality of flat particles are formed by melting and solidifying the particles constituting the second layer, The flat grains are laminated in the direction in which the base material, the first layer and the second layer are laminated.