JP3812715B2 - Recycling method for firing containers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a firing container in which a material to be fired is placed, and in particular, the material to be fired is placed in a firing process of ceramic electronic parts such as dielectrics, soft ferrites and capacitors, or a heat treatment process of ceramic powder such as phosphor powder. This relates to a firing container.
[0002]
[Prior art]
Conventionally, since firing of ceramic electronic components is generally performed in a temperature range of 900 to 1400 ° C., Al is excellent in heat resistance as a firing container on which a material to be fired is placed.₂O₃-SiO₂-MgO quality, MgO-Al₂O₃-ZrO₂And ceramics such as SiC and SiC, and heat-resistant metals such as Mo and Ni-based heat-resistant alloys are used. When a fired product is placed directly on these firing containers and a reaction with the firing container components occurs, it is difficult to react with ZrO which is difficult to react.₂Setters made of materials such as ZrO that is difficult to react on the shelf surface₂A baking container (tool material) coated with a raw material such as JP-A-61-12017, JP-A-61-2225, or JP-A-63-84011 is used.
[0003]
  For example, in the case of soft ferrite (Mn / Zn-based / Ni / Zn-based)₂O₃, ZrO₂Alternatively, a setter or a coated product having the same composition as that of the object to be fired is used properly. The object to be fired is a capacitor (BaTiO₃TiO₂In the case of ZrO₂Setter,OrZrO₂Coating products are mainly used.
[0004]
However, these firing containers often cannot be used for the following reasons. (1) Deformation such as cracking or warping of the substrate itself. (2) Peeling of ceramic film. (3) Reactions such as adhesion occur between the object to be fired and the substrate, and between the object to be fired and the film.
[0005]
These problems often occur as follows. If the components contained in the material to be fired diffuse and permeate from the firing container and these concentrations increase on the surface of the firing container, fusion (such as when the concentration of the flux component increases) or abnormal properties of the material to be fired (For example, when components move between the object to be fired and the container for firing, and the composition of the object to be fired shifts). Further, components contained in the object to be fired diffuse into the film, and further diffuse and penetrate into the base material, thereby degrading the film and the base material, generating a reaction product at the interface between the film and the base material, and peeling the film. In the case where the service life is reached due to the problems of the coatings of the above (2) and (3), the base material itself is hardly damaged and is often at a usable level.
[0006]
In particular, when dense SiC having excellent mechanical properties as compared with an alumina-silica base material is used as a base material, damage such as warpage or cracking of the base material is unlikely to occur, and this is particularly preferable for reuse.
[0007]
For this reason, the reuse of the firing container is also preferable for the global environment from the viewpoint of reducing the firing cost using the firing container and reducing waste.
[0008]
[Problems to be solved by the invention]
Thus, a method for regenerating a container for firing a SiC substrate has been desired.
[0009]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a method for regenerating a firing container capable of reusing a SiC substrate.
[0011]
[Means for Solving the Problems]
  Claims made to achieve the above object1According to the invention, the change in mass per unit area due to surface oxidation is 1 × 10 × 10 when the ceramic part firing object is placed and used at 1400 ° C. in the atmosphere for 100 hours.^-2g / cm²On the surface of the SiC substrate which is the following, Al₂O₃, Mullite, ZrO₂Forming a ceramic coating mainly composed of at least one or more spinelsShiA method for reclaiming a firing container, the container being fired several timesuseAfter that, the ceramic coating on the surface of the SiC base material is removed, and the ceramic coating is newly sprayed with a plasma of 30 to 500 μm and regenerated. Yes.
[0012]
  Claim of this applicationThe invention of 2 is the aboveEven after the firing container is used several times, the SiC substrate has a Vickers hardness of 1800 or more, and the surface roughness of the substrate surface when the old coating is removed as a pretreatment for respraying is Ra = 3. -15 μm1The gist of the method is the method for regenerating a firing container described in 1.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method for regenerating a firing container according to the present invention will be described.
[0014]
In the embodiment of the method for regenerating a firing container according to the present invention, an object to be fired of ceramic parts is placed and used, and the surface of the SiC substrate is made of Al.₂O₃, Mullite, ZrO₂In a method for regenerating a firing container in which a ceramic film mainly composed of at least one or more of spinels is formed, the ceramic film is applied to the surface of the SiC substrate by plasma spraying after the firing container is used several times. Is a way to play.
[0015]
That is, it is a method for reclaiming a firing container for firing an object to be fired, for example, a ceramic electronic component and having a surface having a hardly reactive coating such as zirconia formed thereon. Used as a SiC base material that is excellent in mechanical properties several times compared to the material, and after adjusting the surface of the base material to an appropriate surface roughness, a surface coating is formed using a thermal spraying method. In the event that it becomes impossible to use, it is possible to reuse the firing container by forming a new coating by the thermal spraying method, dramatically extending the service life and reducing the amount of waste in the used firing container. It makes it possible to reduce significantly.
[0016]
As a method of forming a film on the surface of the firing container that becomes the point of recycle use,
(1) Method of baking at high temperature after applying ceramic slurry (2) CVD method
(3) There is a thermal spraying method.
[0017]
In consideration of the formation of a film on a firing container after use (including a large amount of a component to be fired on the surface), a method of baking at a high temperature (1300 to 1600 ° C.) after applying the ceramic slurry of (1) When an attempt is made to regenerate the product after use, the components to be fired (for example, Zn, Ba, Bi, etc.) on the surface of the coating film evaporate during coating baking and contaminate the firing furnace. At the time of baking (held at 1200 to 1600 ° C. for 1 to 6 hours), there was a problem that the component to be fired diffused and moved to the new coating surface. In addition, in such a coating method, the chemical bond between the film and the substrate is the main, so depending on the type and amount of components of the object to be baked, other compounds are generated and the bonding state is not stable. There is.
[0018]
Further, in the CVD method (2), since a film is formed in a decompressed chamber, there are problems such as contamination by a component to be fired and lack of mass productivity.
[0019]
On the other hand, in (3) the thermal spraying method, the temperature on the substrate side is instantaneously high, and there is almost no adverse effect due to evaporation and diffusion of the components to be fired. Construction in the atmosphere is possible, and since a film can be formed in one step, a large amount of processing is possible. In addition, the coating by this thermal spraying method is mainly influenced by the physical engagement (anchor effect) between the surface of the base material (old coating) and the thermal spray coating, and is hardly affected by the presence of the components to be fired. (However, when the surface becomes smooth due to the influence of the component to be fired, the surface must be roughened by shot blasting, chemical etching, or the like). For the above reasons, the thermal spraying method is very suitable for forming a film on a firing container after use.
[0020]
As the function of the sprayed film in the method for regenerating a firing container according to the present invention, (1) the surface portion where the component to be fired is concentrated and the material to be fired are blocked, and (2) the material to be fired at the operating temperature. It is difficult to react even if it is in direct contact with (3), preventing invasion of the components to be fired and protecting the substrate.
[0021]
In addition, the ceramic that forms the sprayed film in this regeneration method is ZrO.₂Of these various thermal spraying methods, a plasma spraying method that can obtain a high temperature is preferable.
[0022]
In re-spraying, there are a case where thermal spraying is performed on the old coating, and a case where the old coating is once removed.
[0023]
When removal of the old film is unnecessary: The film itself does not deteriorate or peel off, but the concentration of the component to be fired on the surface of the film becomes high, causing adhesion or abnormal characteristics of the material to be fired. However, when the component to be fired and the base material component or the coating component produce a reaction product and this is fragile, it is necessary to remove the fragile portion by the method described later. If the reaction product is firmly fixed on the substrate surface, this reaction product is very stable under the conditions of use, so forming a sprayed layer on this surface can dramatically improve the service life. is there. In this case, it is preferable that the surface roughness before re-spraying of the old coating after use several times is Ra = 3 to 15 μm.
[0024]
When it is necessary to remove the old film: This is a case where the film deteriorates during use, and a deteriorated layer is formed at the interface between the substrate and the film, and the film peels off. The film is removed by blasting or the like. In order to remove only the weakened film and prevent damage to the base material and reduction in surface roughness of the base material surface, urea resin, nylon resin, walnut, apricot, etc. are preferable as the grit used for blasting. Since the purpose is to remove only the part weakened by the reaction with the heat cycle and the component to be fired, Al₂O₃A grit of a material having high hardness such as SiC or SiC is not preferable because it impairs the surface state of the roughened substrate. Further, when the hardness of the substrate is low, the substrate portion is damaged by blasting, or the surface roughness Ra is appropriately roughened by the pretreatment corresponding to the initial thermal spraying = 3 to 15 μm. Is unfavorable because it is damaged. In order to avoid such problems and keep the surface roughness of the substrate at Ra = 3 to 15 μm, the substrate needs to have a Vickers hardness of 1800 or more. The base material is easily damaged during blasting for removing water.
[0025]
The timing of re-spraying varies depending on the use temperature, atmosphere, components and amount of the object to be fired, and therefore a preliminary test is performed in advance, and is determined from the time of occurrence of defects such as aging and adhesion of the firing container. There are cases where thermal spraying is performed after the occurrence of a defect and when the preliminary effect of the coating reduces the protective effect of the base material and the deterioration becomes severe, and the coating is re-formed by thermal spraying before the deterioration becomes severe. .
[0026]
As the base material, when considering the regeneration based on the removal of the old film as described above, the film removal method is performed by mechanical impact such as blasting. The base material which has is preferable. Generally, Al₂O₃And ZrO₂In the case of a material that has been densified in order to increase mechanical properties such as bending strength, etc., thermal shock breakdown is likely to occur. In this respect, the SiC material has a very high thermal conductivity, hardly generates thermal stress, and is strong against thermal shock. Therefore, the SiC material is preferable as the base material of the firing container of the present invention. In addition, the high thermal conductivity brings about a great merit as a firing container such that the temperature distribution in the firing container can be made more uniform and the followability to the heat profile is good.
[0027]
However, as a problem of SiC quality, there was a problem of surface oxidation when used in an oxidizing atmosphere. SiO produced by reaction of SiC and oxygen₂Is the main component of electronic ceramic parts BaO and TiO₂Or Fe₂O₃Such a low-melting-point material is easily produced, which tends to cause adhesion between the object to be fired and the firing container, abnormal characteristics of the object to be fired, and poor appearance. In addition, the CaO stabilized ZrO₂When coating a coating, SiO formed at the interface between the substrate and the coating₂Absorbs CaO and ZrO₂There was a problem that the destabilization of the film was promoted and the coating was rapidly deteriorated.
[0028]
Therefore, SiC having excellent oxidation resistance is preferable as the SiC used in the method for regenerating a firing container according to the present invention. The oxidation resistance of various SiC substrates and the peeling resistance of the coating were examined. As a measure of oxidation, in the oxidation resistance test (R1609) defined in JIS, the unit after holding at 1400 ° C. for 100 hours Oxidation increase per area is 1.00 × 10^-2g / cm²The following is preferable. Particularly preferably, a material having a porosity close to 0 such as atmospheric pressure sintered SiC, recrystallized SiC, or Si-impregnated SiC is excellent in oxidation resistance and excellent in peel resistance of the coating film.
[0029]
As described in the respraying method, in the case of a thermal spray coating, the bond between the coating and the substrate is largely due to a physical bond such as an anchor effect. Therefore, the surface roughness of the substrate surface is important. In order to obtain a coating that is difficult to peel off during use, the surface of the substrate is roughened to increase the surface area, thereby increasing the contact area between the coating and the substrate surface. As the surface state, when the average roughness Ra is 3 μm or less, the surface roughness is insufficient and sufficient bonding strength cannot be obtained, so that it is difficult to form a uniform film. Peeling easily occurs. Further, when the surface roughness is increased, the influence of fine cracks generated at the time of roughening is increased and the mechanical strength is lowered. Ra = 15 μm or more is not preferable because the mechanical strength of the base material is greatly reduced, and the probability of cracking during use increases. As the surface roughness of the substrate, Ra = 3 to 15 μm is preferable, and Ra = 8 to 12 μm is most preferable.
[0030]
The film thickness varies depending on the shape of the tool material and the material type of the base material, but an effect is obtained if it is 0.03 mm or more. If it is too thick, the residual stress generated at the time of thermal spraying peculiar to thermal spraying will increase and peeling will easily occur. The standard size of current baking containers is a rectangle with an outer diameter of 100 to 300 mm and a thickness of 3 to 10 mm. When such a container is assumed, the thickness of the coating is preferably 0.03 to 0.50 mm. In the thermal spraying method, residual stress is generated at the time of thermal spraying. Therefore, if the film thickness is excessively increased, the film is warped or peeled off due to the residual stress, so that the film thickness is limited.
[0031]
When the water plasma spraying method is used, it is possible to spray a relatively thick film, but 0.5 mm is the limit for use in the method for regenerating a firing container according to the present invention. It is easy to generate. However, in the case of respraying, the residual stress of the old sprayed coating is relaxed as the temperature rises and falls, and the residual stress of the old sprayed coating and the residual stress of the resprayed coating are synthesized by respraying. Since peeling does not occur, the total thickness with the old film may be 0.5 mm or more. As an undercoat, Al₂O₃Mullite is suitable. The characteristics required for the surface coating are poor reactivity with the object to be fired and durability (peeling and dropping). ZrO₂Has been used as a conventional setter material, coating material or bedding powder due to its poor reactivity. CaO or Y when used as a setter or coating layer₂O₃Stabilized or partially stabilized ZrO₂Is often used. Unstable ZrO₂When the temperature rises and falls in the firing process, volume change occurs in the vicinity of 1000 ° C due to the phase transformation of monoclinic crystal ← → tetragonal crystal (cubic crystal).₂When it is manufactured and used, it is rarely used because it easily breaks and drops off particles. However, since it does not contain a stabilizer and has good reactivity, it is often used as a bedding powder. Such a material is also suitable as a surface coating material in the method for regenerating a firing container according to the present invention. Depending on the application, calcium zirconate (CaZrO₃), Barium zirconate (BaZrO)₃), Strontium zirconate (SrZrO)₃) ・ Magnesium zirconate (MgZrO)₃Zirconate salts such as) may be preferable in terms of reactivity and durability. In addition, Al for alumina insulators and ferrites₂O₃Thermal spray, Bi₂O₃Spinel spraying is suitable for applications in which the object to be fired contains a large amount of PbO or the like.
[0032]
In addition, the reproduction | regenerating method of the container for baking concerning this invention is applicable not only to a container-shaped board | substrate but to a board-shaped board | substrate.
[0033]
【Example】
(Example 1) Mn-Zn ferrite
The surface of an atmospheric pressure sintered SiC plate (200 × 200 × 10 mm) having an apparent porosity of 0% with SiC of 97% is roughened to a surface roughness Ra = 9 μm, and then an alumina raw material (Al₂O₃= 99.5%) was sprayed to form an alumina coating having a thickness of 0.3 mm, and a plate-shaped baking container was produced.
[0034]
The mass change per unit area in the oxidation test of this SiC substrate alone (held at 1400 ° C. for 100 hours) was 1.00 × 10^-4g / cm²Met. The method for the oxidation test was performed in accordance with the oxidation resistance test method for non-oxide fine ceramics of JIS R1609. The test piece was 3 × 4 × 40 mm, the surface roughness was 0.2a or less on the entire surface, the ridge portion was chamfered, and the number was 10. The test was carried out in the atmosphere, the test piece was placed on a support as shown in FIG. 1, the change in mass before and after being held at 1400 ° C. for 100 hours was measured, and the oxidation resistance was evaluated by the change in mass per unit area.
[0035]
A Mn—Zn ferrite molded body (φ30 × 3 mm) was placed on the plate and fired at 1350 ° C. for 2 hours. When this operation was repeated, the alumina coating particles were attached to the Mn—Zn ferrite sample for the 25th time. At this time, since the alumina coating became brittle and particles were dropped, the alumina coating was temporarily removed using blasting. Blasting was performed using a JIS abrasive particle size # 46 urea resin as a grit and a suction type blasting apparatus at an ejection pressure of 0.4 MPa. The surface roughness of the SiC plate surface after removal of the old film was Ra = 8 μm. Again on this plate surface, water plasma spraying Al₂O₃(Purity: 99.5%) was sprayed to form a film having a thickness of 0.3 mm. When Mn—Zn ferrite was baked using this plate, no adhesion occurred, and the alumina sprayed coating partially peeled off at the 20th time (45 times in total), but the substrate was not damaged. After removing the alumina coating again using shot blasting (surface roughness Ra = 7.5 μm), water plasma spraying is used to produce Al.₂O₃Was sprayed (conditions were the same as before). Firing was repeated using this plate. In the 30th time (75th time in total), the alumina sprayed coating was partially peeled off, so the use was stopped. Re-spraying was performed under the same conditions as described above, and the test was continued. Finally, the test was conducted up to 100 times in total, but no damage to the substrate was observed. Re-spraying was performed three times in total.
[0036]
(Example 2) Mn-Zn ferrite
After roughening the surface of an atmospheric pressure sintered SiC plate (200 × 200 × 10 mm) with SiC 97% and apparent porosity of 0% to a surface roughness Ra = 10 μm, an intermediate layer is formed using a water plasma spraying method. Coat (Al₂O₃: 99.5%) Further, a surface layer coat (8% Y)₂O₃-ZrO₂: 99.5%) to form a plate-shaped baking container.
[0037]
A Mn—Zn ferrite compact (φ30 × 3 mm) was placed on this plate and fired at 1350 ° C. for 2 hours. When this operation was repeated 30 times, discoloration was observed on a part of the surface contacting the surface of the thermal spray coating of the Mn—Zn ferrite sample at the 30th time. When this part was magnified and observed, the surface crystal grains grew abnormally and became coarse. At this time, the surface of the sprayed coating on the plate was discolored due to the ferrite component adhering thereto, but it was not weakened. Further, the surface roughness of the coating surface was about Ra = 10 μm, and the surface roughness was sufficient for spraying. Therefore, the surface of the coating is 8% Y by water plasma spraying.₂O₃-ZrO₂(Purity = 99.5%) was sprayed to form a 0.2 mm thick coating. When Mn-Zn ferrite is fired using this plate, no adhesion occurs, and it can be used 25 times (total 55 times), and the same phenomenon as described above occurs at the 26th time (total 56 times). As a result, 8% Y was again applied to the coating surface by water plasma spraying.₂O₃-ZrO₂(Purity: 99.5%) was sprayed to form a coating having a thickness of 0.2 mm. Furthermore, since the same phenomenon as described above occurred at the time of using 24 times (80 times in total), re-spraying was performed under the same conditions as described above, and the test was continued. Finally, a total of 100 tests were conducted. During this time, re-spraying was performed four times.
[0038]
(Example 3) BaTiO ₃ Dielectrics
After roughening the surface of an atmospheric pressure sintered SiC plate (200 × 200 × 4 mm) having an apparent porosity of 0% with the same SiC 97% as in Example 1 to Ra = 8 μm, a sprayed coating (intermediate layer) Coat: Mullite and surface layer coat: 4% Y₂O₃-ZrO₂The film thickness was 0.1 mm each. Thermal spraying was performed by gas plasma spraying. BaTiO on this plate₃A dielectric molded body (φ30 × 3 mm) having as a main component was placed and fired at 1350 ° C. for 2 hours. When this operation was repeated 20 times, it became attached to the sprayed coating at the 20th time. Therefore, 4% Y is applied to the surface of the coating by gas plasma spraying.₂O₃-ZrO₂(Purity: 99.5%) was sprayed to form a 0.05 mm thick film. When the same baking was performed using this plate, adhesion did not occur, and it was possible to use 15 times (35 times in total), and the same phenomenon as described above occurred at the 16th time (36 times in total). Again 4% Y by gas plasma spraying on the coating surface₂O₃-ZrO₂(Purity: 99.5%) was sprayed to form a 0.05 mm thick film. Furthermore, since the same phenomenon as described above occurred when it was used 17 times (the 53rd time in total), re-spraying was performed under the same conditions as described above, and the test was continued. Finally, the test was conducted up to 100 times in total, but no damage to the substrate was observed. Re-spraying was performed 6 times in total.
[0039]
(Comparative Example 1) (Recoating by baking method in the same application as Example 2)
Al₂O₃: 70%, SiO₂: Al whose main component is alumlite with 28% and apparent porosity of 20%₂O₃-SiO₂Alumina slurry (alumina purity 99.5%) was sprayed on the surface of a quality plate (200 × 200 × 10 mm) and then baked at 1450 ° C. to produce an alumina coating. A Mn—Zn ferrite molded body (φ30 × 3 mm) was placed on the plate and fired at 1350 ° C. for 2 hours. When this operation was repeated three times, the alumina particles of the alumina coating adhered to the Mn—Zn ferrite sample at the fourth time.
[0040]
At this time, since the alumina coating became brittle and particles dropped out, the alumina coating was once removed using shot blasting, and then the alumina slurry (alumina purity 99.5%) was sprayed, and then 1450 ° C. A film was prepared by baking. The film was discolored in green, and the film warped and peeled off at the end. Also, the furnace material used for baking (Al₂O₃The surface of the main component was green. For this reason, it was judged that recoating by the baking method was difficult for this application.
[0041]
(Comparative Example 2) (Recoating by the same baking method as in Example 3)
SiC: The surface of an atmospheric pressure sintered SiC plate (200 × 200 × 4 mm) having an apparent porosity of 0% or more with 97% or more is roughened by chemical etching, and then a thermal spray coating (intermediate layer coating: mullite, Surface layer coat: 4% Y₂O₃-ZrO₂) Was formed. Thermal spraying was performed by gas plasma spraying. BaTiO on this plate₃A dielectric molded body (φ30 × 3 mm) having as a main component was placed and fired at 1350 ° C. for 2 hours. When this operation was repeated 16 times, the dielectric sample came to adhere to the sprayed coating surface at the 16th time. Therefore, zirconia slurry (4% Y₂O₃-ZrO₃) And then baked at 1450 ° C. to produce a coating. Cracks occurred in a part of the film, and the color of the film surface was uneven with yellow and orange parts depending on the location. When the same firing test as described above was performed using this plate, partial adhesion occurred between the dielectric and the coating from the first time.
[0042]
(Comparative Example 3) (Coat and base material different in the same manner as in Example 3)
The surface of a SiC plate (200 × 200 × 4 mm) with SiC: 90% and apparent porosity of 7% is roughened to Ra = 8 μm, and then sprayed coating (intermediate layer coat: mullite, surface layer coat: 4% Y₂O₃-ZrO₂The film thickness was 0.1 mm each. Thermal spraying was performed by gas plasma spraying. In addition, when the oxidation test similar to Example 1 was done about this base material, the mass change per unit area was 1.5x10.^-1g / cm²Met. BaTiO on this plate₃A dielectric molded body (φ30 × 3 mm) having as a main component was placed and fired at 1350 ° C. for 2 hours. When this operation was repeated 5 times, the film was partially peeled off. When the old film was removed by blasting similar to Example 2, it was confirmed that a glass layer was formed on the surface of the substrate.
[0043]
【The invention's effect】
According to the method for regenerating a firing container according to the present invention, a method for regenerating a container for firing a SiC substrate can be provided.
[0044]
In other words, ceramic parts to be fired are placed and used, and the surface of the SiC substrate is made of Al.₂O₃, Mullite, ZrO₂In the method for regenerating a firing container in which a ceramic film mainly composed of at least one or more of the spinels is formed, after the firing container is used several times, the ceramic film is formed on the surface of the SiC substrate by 30 to 500 μm. Since plasma spraying and regeneration are performed, the object to be fired is placed and used, and Al is applied to the surface of the SiC substrate.₂O₃It can be reused by forming a coating by thermal spraying on the surface of the container for firing that has become unusable due to problems such as adhesion to the mullite and the object to be baked, peeling of the coating, etc. The life can be extended by forming a new coating on the surface coating of the container for use by thermal spraying during use.
[0045]
Further, the SiC base material has a mass change of 1 × 10 per unit area due to surface oxidation when kept at 1400 ° C. in the atmosphere for 100 hours.^-2g / cm²Since it is below, a material is excellent in oxidation resistance and is excellent also in the peeling resistance of a film.
[0046]
Further, the hardness of the SiC base material after use of the firing container several times is Vickers hardness of 1800 or more, and the surface roughness of the base material surface when the old film is removed as a pretreatment for re-spraying is Ra = Since it is 3-15 micrometers, the damage of a base material does not generate | occur | produce at the time of blasting for removing an old film, surface roughness is ensured, and a firm film can be formed.
[0047]
Further, in the firing container, the surface roughness before re-spraying of the old coating after several times of use is Ra = 3 to 15 μm, so that the strong coating on the old coating without removing the old coating. Can be formed.
[0048]
Moreover, the firing container is made of Al formed on the surface of the SiC substrate.₂O₃Or 3Al₂O₃・ 2SiO₂On the surface of the sprayed coating of CaO, Y₂O₃, MgO, CeO stabilized zirconia layer or unstable ZrO₂A layer, or a zirconate salt with an alkaline earth gold layer such as CaO or SrO, or a layer composed of a plurality of these layers, and each layer has a thickness of 30 to 500 μm, so that it has reactivity and durability. Excellent life expectancy.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a test method of an example.

Claims (2)

A SiC-based substrate having a mass change per unit area of 1 × 10 ⁻² g / cm ² or less due to surface oxidation when the ceramic part firing object is placed and used in air at 1400 ° C. for 100 hours. A method for reclaiming a firing container in which a ceramic film mainly composed of at least one or more of Al ₂ O ₃ , mullite, ZrO ₂ , and spinel is formed on the surface of the material, and this firing container is used several times Then, the ceramic coating on the surface of the SiC base material is removed, and the ceramic coating is newly sprayed with a plasma of 30 to 500 μm to regenerate the firing container. Even after the firing container is used several times, the SiC substrate has a Vickers hardness of 1800 or more, and the surface roughness of the substrate surface when the old coating is removed as a pretreatment for re-spraying is Ra = The method for regenerating a firing container according to claim 1 , wherein the method is 3 to 15 μm.

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