JPH101370A - Jig for heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost jig for heat treatment small in residual expansion at a heat treating time and excellent in thermal impact resistance by constituting the jig of a specific zirconia-matter obtained by mixing specific zirconia with CaCO3 , forming and sintering the mixture. SOLUTION: This jig for heat treatment is constituted of the zirconia-matter dispersed with a high concentration area of Ca at the particle boundary, and is obtained by mixing 100 pts.wt. (hereafter pts.) the zirconia having 70-90wt.% stability ratio stabilized with solid solution of CaO with 0.5-6.0 pts. CaCO3 , forming and sintering the mixture. Also jig is obtained by mixing 100 pts. the above-zirconias with 0.5-6.0 pts. CaCO3 , 0.3-5.0 pts. Fe2 O3 or 0.5-6.0 pts. CaCO3 and 0.3-5.0 pts. BaTiO3 and forming and sintering the mixture. This jig is constituted of the zirconia-matter dispersed with a high concentration area of Ca and Fe at the particle boundary or with a high concentration area of Ca, Ba and Ti at the particle boundary. Thus, the mechanical strength is further enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment jig suitable for heat treatment and heat baking of functional ceramics such as electronic parts and the like or powders or compacts of various powder metallurgy.

[0002]

2. Description of the Related Art Zirconia (ZrO ₂ ) is used in the firing of functional ceramics such as electronic parts, the heat treatment of raw material powders of various powder metallurgy, or the heating and firing of compacts.
Quality heat treatment jigs are used. In particular, when firing ceramic capacitors, piezoelectric bodies, sensors, and ferrite magnetic bodies, zirconia-based jigs that hardly react with the fired body, have little component movement between the fired bodies, and have little influence on the fired body, Alternatively, a jig in which a zirconia layer is coated on a substrate surface is used.

[0003] By the way, pure zirconia is 1000
The transformation of the monoclinic and tetragonal crystal structures occurs around ℃, and the volume rapidly changes with this transformation. For this reason, when a ceramic capacitor, a piezoelectric material, a sensor, and a ferrite magnetic material are fired using a heat treatment jig made of pure zirconia, a temperature rise from room temperature to a heat treatment temperature (1000 to 1500 ° C.) and a high temperature In this case, a rapid change in volume causes cracks in the heat treatment jig, making it difficult to use the jig many times.

Therefore, high-temperature type cubic crystals (partially tetragonal crystals) are stabilized at a low temperature of 1000 ° C. or less by dissolving CaO, Y ₂ O ₃ , MgO, etc., into stabilized zirconia or zirconia. A heat treatment jig made of partially stabilized zirconia partially stabilized has been used.

However, when an object to be heat-treated, for example, an object to be fired is fired by using a heat-treating jig made of stabilized zirconia, a stabilizing component such as CaO or the like dissolved in a heat cycle of heating and cooling during firing is obtained. Escapes to the grain boundaries, destabilization proceeds, and the proportion of monoclinic ZrO ₂ increases. As a result, a so-called residual expansion occurs, in which the strength of the jig is reduced and the volume after the heat treatment is increased as compared with before the heat treatment, and deformation, cracks, and the like are caused accordingly. In particular, when residual expansion occurs partially, cracks are likely to occur.

Also, Y ₂ O ₃ and CeO are used as stabilizing components.
When these are used, since these stabilizing components are expensive, the price of the jig is increased. On the other hand, CaO as a stabilizing component is relatively inexpensive and is advantageous in cost. However, depending on the amount of CaO added to zirconia (the amount of solid solution), the properties of CaO change in a direction in which the thermal shock resistance decreases, such as a decrease in strength and an increase in thermal expansion coefficient. Cracks occur due to impact,
It can be used only under slow heat treatment conditions of a heating rate and a cooling rate.

For these reasons, Japanese Patent Application Laid-Open No. 2-2526
No. 56 discloses a zirconia refractory used for kiln tools in which a solid solution stabilizer of calcium acetate or magnesium acetate is added to stabilized zirconia, and the progress of destabilization is suppressed by firing. . However, when using a solid solution stabilizer such as calcium acetate or magnesium acetate that dissolves in water, it is necessary to adopt a molding method that requires moisture even during molding, such as slip casting. At the time of drying, CaO segregates at a portion where moisture evaporates slowly. As a result, in order to suppress the progress of the destabilization of the obtained zirconia refractory, it is necessary to increase the amount of the solid solution stabilizer, as well as to increase the amount of segregated Ca.
There was a problem that O became a structural defect.

Japanese Patent Application Laid-Open No. Hei 2-263762 discloses a method of adding a solid solution stabilizer of calcium acetate or magnesium acetate and zirconyl acetate to stabilized zirconia and calcining the zirconia to delay the destabilization and improve the strength. Zirconia refractories for use in kiln tools are disclosed. However, such a zirconia refractory is disclosed in
As in the case of JP-A-252656, there is a problem in that the amount of the solid solution stabilizer added is increased, and structural defects are caused by segregated CaO. In addition, since zirconyl acetate is expensive, the price of the refractory increases.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment jig made of inexpensive zirconia material which has small residual expansion during heat treatment and has excellent thermal shock resistance. Another object of the present invention is to provide a heat treatment jig made of inexpensive zirconia material which has small residual expansion during heat treatment, has excellent thermal shock resistance, and has improved mechanical strength.

[0010]

The jig for heat treatment according to the present invention has a stabilization rate stabilized by solid solution of CaO of 7%.
It is obtained by mixing 0.5 to 6.0 parts by weight of CaCO ₃ with 100 parts by weight of zirconia of 0 to 90%, molding and firing, and is made of zirconia having a high concentration region of Ca dispersed in grain boundaries. It is characterized by the following.

Here, the grain boundary means between zirconia single crystal particles or between aggregates of several zirconia single crystal particles. A high Ca concentration means that it is not lower than the Ca concentration in the stabilized zirconia.

Further, the term “dispersion” includes the meanings of “scattered” and “scattered”, that is, it is only necessary that a high concentration region of Ca is formed at a uniform ratio at grain boundaries. Such a jig for heat treatment has a C
The zirconia in which the high concentration region of a is dispersed has a stabilization ratio of 70.
Since it is about 90%, the thermal shock resistance is improved, and it is possible to prevent cracks from being generated in a heat cycle when the heat treatment is performed on the heat treatment target.

Further, a predetermined amount of CaCO ₃ is added as a Ca source to zirconia having the above stabilization ratio, and the mixture is mixed.
By shaping and firing, a zirconia material in which Ca is uniformly dispersed in the grain boundaries can be obtained. As a result, deformation due to maintaining strength and remaining expansion by suppressing the progress of destabilization,
Cracking can be prevented. These effects are
It is presumed to be due to the following behavior.

The destabilization is performed by dissolving CaO dissolved in a heat cycle during heat treatment of the object to be fired using the jig of the present invention.
Is diffused and escapes to the zirconia grain boundaries.
It is considered that the diffusion of CaO into the grain boundaries depends on the Ca concentration in the grain boundaries. As described above, by adding CaCO ₃ to disperse Ca at the grain boundaries and increasing the Ca concentration at the grain boundaries in advance, it is possible to suppress the diffusion of solid solution CaO to the grain boundaries during the thermal cycle, and as a result, It is considered that the stabilized state of zirconia can be maintained for a long period of time, and the progress of destabilization can be suppressed. Also, C
Since CaCO ₃ is added as a source in the form of fine powder that is difficult to dissolve in water, it can be uniformly dispersed without segregation at the grain boundaries unlike calcium acetate,
O can be prevented from locally diffusing into the zirconia grain boundary and coming off, suppressing the occurrence of residual expansion, and preventing the accompanying deformation and cracking.

Therefore, according to the present invention, there is provided a heat treatment jig made of inexpensive zirconia material which has small residual expansion during heat treatment, has excellent thermal shock resistance, can withstand long-term use, has good handleability during use, and is inexpensive. Can be provided.

Another jig for heat treatment according to the present invention is Ca
CaCO ₃ is added in an amount of 0.5 to 6.0 to 100 parts by weight of zirconia having a stabilization rate of 70 to 90% stabilized by solid solution of O.
Parts by weight, and 0.3 to 5.0 parts by weight of Fe ₂ O ₃ are mixed, molded and calcined to obtain a partially stabilized zirconia material in which a high concentration region of Ca and Fe is uniformly dispersed in grain boundaries. It is characterized by consisting of.

In another heat treatment jig according to the present invention, similarly to the heat treatment jig described above, the thermal shock resistance is improved and cracks occur in a heat cycle when heat-treating the object to be fired. Can be prevented, and the progress of destabilization can be suppressed to maintain strength and prevent deformation and cracking due to residual expansion. Further, Fe is dispersed in the grain boundary together with Ca to form a strong binder phase, so that the mechanical strength can be improved. As a result, the partial residual expansion during heat treatment is small, and the thermal shock resistance is excellent,
Further, it is possible to provide a heat treatment jig made of inexpensive zirconia material having improved mechanical strength and good handling properties that can withstand long-term use.

Further, in the jig, since the additive component to the grain boundary contributing to the improvement of the strength is Fe, it is considered that the jig has an adverse effect on the characteristics of the object to be processed at the time of heat treatment, for example, considering the reactivity.
This is suitable for firing ferrite containing as one component.

Still another jig for heat treatment according to the present invention has a stabilization rate of 70 to 70 stabilized by solid solution of CaO.
CaCO ₃ is added to 100 parts by weight of 90% zirconia with 0.5
6.0 parts by weight of a BaTiO ₃ were mixed 0.3 to 5.0 parts by weight, molding, obtained by baking, Ca, high density area of Ba and Ti is uniformly dispersed in the grain boundary portion It is characterized by being composed of stabilized zirconia.

In another heat treatment jig according to the present invention, similarly to the heat treatment jig described above, the thermal shock resistance is improved, and cracks occur in a heat cycle when heat-treating the object to be fired. Can be prevented, and the progress of destabilization can be suppressed to maintain strength and prevent deformation and cracking due to residual expansion. In addition, Ba and T
Since i is coexisted and dispersed with Ca to form a strong binder phase, mechanical strength can be improved. As a result, a heat treatment jig made of inexpensive zirconia material that has small residual expansion during heat treatment, has excellent thermal shock resistance, has improved mechanical strength, and can handle long-term use and has good handling properties. Can be provided.

Further, in the jig, Ba and Ti are added to the grain boundaries that contribute to the improvement of the strength. Therefore, when considering the adverse effect on the properties of the workpiece during the heat treatment, for example, the reactivity, Ba and Ti are reduced to one. It is suitable for firing a ceramic capacitor based on a dielectric material as a component.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat treatment jig according to the present invention will be described in detail. The jig for heat treatment according to the present invention,
The stabilization rate stabilized by the solid solution of CaO is 70 to 90.
% Of zirconia in 100 parts by weight of CaCO ₃
It is obtained by mixing 6.0 parts by weight, molding and firing, and is made of zirconia having a high concentration region of Ca dispersed in the grain boundaries.

The zirconia having the above-mentioned stabilization rate undergoes transformation of monoclinic and tetragonal crystal structures around 1000 ° C. like unstabilized zirconia, thereby avoiding abrupt volume change. it can. When the stabilization ratio due to the solid solution of CaO is less than 70%, the influence of the volume change due to the transformation becomes large, and cracks occur during use, and the occurrence of partial residual expansion becomes remarkable. On the other hand, the CaO
If the stabilization rate of the solid solution exceeds 90%, the expansion rate increases, and the thermal shock resistance decreases.

It is preferable that the particle size of the zirconia having the above-mentioned stabilization rate is adjusted depending on the heat treatment conditions used. For example, in applications where the thermal shock is severe, it is effective to obtain a particle size distribution including large zirconia particles. Also,
In consideration of formability, it is preferable that the coarsest zirconia particles be one third or less of the thinnest part of the final product.

Even when water is used at the time of mixing with zirconia having a predetermined stabilization ratio, the CaCO ₃ is relatively hardly soluble in water, so that Ca segregation in the drying step is small, and the particle size after firing is low. Ca can be uniformly dispersed in the field. The zirconia 100 of the CaCO ₃
When the compounding ratio with respect to parts by weight is less than 0.5 parts by weight,
It becomes difficult to sufficiently achieve the effect of addition, that is, the effect of suppressing the progress of destabilization. On the other hand, the mixing ratio of the CaCO ₃ to 100 parts by weight of the zirconia is 6.0.
When the amount is more than the weight part, there is a possibility that the heat treatment object adheres to the obtained heat treatment jig or the properties of the heat treatment material are adversely affected. A more preferable mixing ratio of the CaCO ₃ to 100 parts by weight of the zirconia is 1.0 to 4.0 parts by weight.

As for the particle size of the CaCO ₃ , the finer and the larger the surface area, the greater the effect of addition.
m or less. The heat treatment jig according to the present invention is manufactured by, for example, the following method.

First, 0.5 to 6.0 parts by weight of CaCO ₃ powder is added to 100 parts by weight of zirconia particles having a stabilization rate of 70 to 90% stabilized by solid solution of CaO, and these are mixed. I do. In order to sufficiently exert the effect of adding CaCO ₃ , it is preferable that the CaCO ₃ powder is sufficiently dispersed in a solvent by a mixing method such as a wet ball mill and mixed with the zirconia particles. Subsequently, the mixture is granulated to a particle size suitable for a molding method, and then molded. As a molding method, a method of pouring into a mold such as a gypsum mold may be adopted. Thereafter, the molded body is placed between 1300 and 170
The jig for heat treatment is manufactured by baking in the air at a temperature of 0 ° C. The firing is allowed to be performed in any of oxygen, nitrogen, hydrocarbon, ammonia, hydrogen, or a mixed gas thereof in addition to the air atmosphere.

Another jig for heat treatment according to the present invention is Ca
CaCO ₃ is added in an amount of 0.5 to 6.0 to 100 parts by weight of zirconia having a stabilization rate of 70 to 90% stabilized by solid solution of O.
Part by weight and 0.3 to 5.0 parts by weight of Fe ₂ O ₃ are mixed, molded and fired, and made of zirconia having a high concentration region of Ca and Fe dispersed in grain boundaries. .

The Fe ₂ O ₃ has the function of improving the mechanical strength of the heat treatment jig and reducing the residual expansion. If the mixing ratio of Fe ₂ O ₃ to 100 parts by weight of the zirconia is less than 0.3 parts by weight, it is difficult to sufficiently achieve the effect of adding Fe ₂ O ₃ , that is, the effect of improving mechanical strength. On the other hand, if the mixing ratio of Fe ₂ O ₃ to 100 parts by weight of the zirconia exceeds 5.0 parts by weight, the object to be heat-treated adheres to the heat treatment jig or adversely affects the properties of the heat-treated material. A more preferable mixing ratio of the Fe ₂ O ₃ to 100 parts by weight of the zirconia is 0.5 to 2.5 parts by weight.

The finer the particle size of Fe ₂ O ₃ is, the larger the surface area is.
m or less. Yet another jig for heat treatment according to the present invention is a method in which 100 parts by weight of zirconia stabilized by solid solution of CaO and having a stabilization rate of 70 to 90% are added to Ca.
CO ₃ is obtained by mixing 0.5 to 6.0 parts by weight of CO ₃ and 0.3 to 5.0 parts by weight of BaTiO ₃ , followed by molding and firing, and a high concentration region of Ca, Ba and Ti is present at the grain boundaries. It is composed of dispersed zirconia.

The BaTiO ₃ has the effect of improving the mechanical strength of the heat treatment jig and reducing the residual expansion. If the mixing ratio of the BaTiO ₃ to 100 parts by weight of the zirconia is less than 0.3 parts by weight, it is difficult to sufficiently achieve the effect of the addition, that is, the effect of improving the mechanical strength. On the other hand, if the mixing ratio of the BaTiO ₃ with respect to 100 parts by weight of the zirconia exceeds 5.0 parts by weight, the object to be heat-treated adheres to the jig for heat treatment or adversely affects the characteristics of the heat-treated material. The BaTiO
A more preferable mixing ratio of ₃ to 100 parts by weight of the zirconia is 0.5 to 2.5 parts by weight. The BaT
As the particle size of iO ₃ becomes finer and the surface area becomes larger, the effect of addition becomes larger and more advantageous. For example, the particle size is preferably 50 μm or less.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail. (Example 1) C having a particle size of more than 30 μm and not more than 50 μm
35 parts by weight of partially stabilized zirconia particles stabilized by aO and having a stabilization rate of 90% are mixed with CaCO having an average particle diameter of about 5 μm.
₃ 0.5 parts by weight of powder and 10.5 parts by weight of water were added and mixed by a wet ball mill method for 6 hours. Subsequently, 65 parts by weight of partially stabilized zirconia particles having a stabilization rate of 90% exceeding 350 μm and not more than 1000 μm were added to the slurry, and mixed, kneaded, and granulated with a stirrer to prepare a raw material for molding. The particle size distribution of the partially stabilized zirconia particles in the raw material has a value shown in A of Table 1 below. Subsequently, this raw material was 300 × 30 using a bumping press.
It was formed into a plate shape with a size of 0 × 5 mm. The molded body was air-dried, forcibly dried at 100 ° C., and then fired by holding it at 1500 ° C. for 3 hours in the air using an electric furnace to produce a plate-shaped sintered body. .

[0033]

[Table 1]

(Examples 2 to 5, Comparative Examples 1 to 4)
The stabilized zirconia particles having a stabilization ratio and a particle size distribution shown in Table 2 and a CaCO ₃ powder having a compounding amount shown in Table 2 (average particle size 5 μm)
Eight types of plate-shaped sintered bodies were manufactured in the same manner as in Example 1 except that powders of Fe ₂ O ₃ and an average particle size of 5 μm were used.

Comparative Example 5 Stabilized zirconia particles having a stabilization ratio and a particle size distribution shown in Table 2 below, and calcium acetate [(CH ₃ CO ₂ ) ₂ Ca.H ₂ O] powder having a compounding amount shown in Table 2 A plate-like sintered body was manufactured in the same manner as in Example 1 except that (average particle size: 5 μm) was used. However, the amount of calcium acetate added was set so as to be the same as in Example 1 in terms of CaO.

The obtained Examples 1 to 5 and Comparative Examples 1 to 5
Of the sintered body, the bending strength at room temperature, the coefficient of thermal expansion at 1000 ° C., the residual expansion coefficient, the thermal shock resistance, and the state of the ferrite after firing the ferrite were examined. The results are shown in Table 3 below.

The residual expansion coefficient is 1% from the plate-like sintered body.
A test piece of 10 × 25 × 5 mm was cut out, and 13
After maintaining at 50 ° C. for 30 minutes, the temperature was lowered to room temperature. After repeating this operation 15 times, the length dimension is measured,
It was calculated from the expansion coefficient relative to the dimension before heating.

As for the thermal shock resistance, a test piece of 110 × 110 × 5 mm was cut out from the plate-like sintered body, and as shown in FIG. The sintering body 4 is placed on the test piece 1 and placed in a furnace maintained at a predetermined temperature shown below.
After holding for a minute, the sample was taken out of the furnace, air-cooled at room temperature, and evaluated by observing the presence or absence of cracks in the test piece after the heat treatment. However, this operation is performed at 500 ° C., 550 ° C.,
600 ° C, 650 ° C, 700 ° C, 750 ° C and 800
Each test was repeated three times at ° C, and the temperature was indicated at the temperature at which cracks occurred. In addition, ferrite was used as the sintered body, and the state of the ferrite after firing was observed and evaluated.

[0039]

[Table 2]

[0040]

[Table 3]

As is clear from Tables 2 and 3, the sintered bodies of Examples 1 to 5 have good bending strength, a coefficient of thermal expansion at 1000 ° C., a coefficient of residual expansion, and thermal shock resistance. It can be seen that there is no characteristic deterioration to ferrite.

On the other hand, the sintered body of Comparative Example 1 in which the amount of CaCO ₃ powder added is less than the range of the present invention (0.5 to 6.0 parts by weight) has a large residual expansion coefficient. You can see that. The stabilization rate by CaO is within the range of the present invention (7).
It can be seen that the sintered body of Comparative Example 2 using the partially stabilized zirconia smaller than 0 to 90%) has a low flexural strength, a large residual expansion coefficient, and cracks at low temperatures. The addition amount of the CaCO ₃ powder falls within the range of the present invention (0.
It can be seen that the sintered body of Comparative Example 3 using a raw material exceeding 5 to 6.0 parts by weight) has a reduced bending strength. It can be seen that the sintered body of Comparative Example 5 using calcium acetate as a Ca source has a large residual expansion coefficient. On the other hand, the amount of Fe ₂ O _{3 as} an additive falls within the range of the present invention (0.3 to 5.0).
It can be seen that when the ferrite is fired by the sintered body of Comparative Example 4 using a raw material exceeding the above, discoloration is caused and characteristics are deteriorated.

EXAMPLE 6 100 parts by weight of partially stabilized zirconia particles having a particle size distribution shown in Table 1B and stabilized by CaO and having a stabilization rate of 80% were added to an average particle size of 5 μm.
Of CaCO ₃ powder and 30 parts by weight of water were added and mixed by a wet ball mill method for 12 hours. Subsequently, the slurry was spray-dried and granulated using a spray dryer, and then 110 × 110 by a hydraulic uniaxial press.
It was formed into a plate having a size of × 5 mm. The molded body was air-dried and further forcibly dried at 100 ° C., and then fired by holding it at a temperature of 1400 ° C. for 3 hours in the air using an electric furnace to produce a plate-shaped sintered body. .

(Examples 7 to 9 and Comparative Example 6) Table 4 below
The stabilized zirconia particles having a stabilization ratio and a particle size distribution shown in Table 4 and a CaCO ₃ powder having an amount shown in Table 4 (average particle size 5 μm)
Four types of plate-like sintered bodies were manufactured in the same manner as in Example 6, except that BaTiO ₃ powder (average particle size: 5 μm) and BaTiO ₃ powder were used.

With respect to the obtained sintered bodies of Examples 6 to 9 and Comparative Example 6, the bending strength at room temperature, the coefficient of thermal expansion at 1000 ° C., the coefficient of residual expansion, the thermal shock resistance, and the composition mainly containing BaTiO ₃ were used. The state of the capacitor after firing the ceramic capacitor was examined. The results are shown in Table 5 below.

The residual expansion coefficient is determined by cutting a 110 × 25 × 3 mm test piece from the plate-like sintered body,
After maintaining at 350 ° C. for 30 minutes, the temperature was lowered to room temperature. After repeating this operation 15 times, the dimension in the length direction was measured and calculated from the expansion rate with respect to the dimension before heating.

The thermal shock resistance of the plate-shaped sintered body (1
10 × 110 × 5 mm) as a test piece, and this test piece 1 is supported at four points by four columns 3 arranged on a holding plate 2 as shown in FIG. The body 4 is placed and placed in a furnace maintained at a predetermined temperature shown below.
After holding for 0 minutes, the sample was taken out of the furnace, air-cooled at room temperature, and evaluated by observing the presence or absence of cracks in the test piece after the heat treatment. However, this operation was performed at 500 ° C. and 550 ° C.
℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃ and 8
Each test was repeated three times at 00 ° C., and indicated by the temperature at which cracks occurred. Further, a ceramic capacitor containing BaTiO ₃ as a main component was used as the sintered body, and the state of the fired capacitor was observed and evaluated.

[0048]

[Table 4]

[0049]

[Table 5]

As apparent from Tables 4 and 5, the sintered bodies of Examples 6 to 9 have good bending strength, a coefficient of thermal expansion at 1000 ° C., a coefficient of residual expansion, and thermal shock resistance. It can be seen that there is no adhesion of the ceramic capacitor.

On the other hand, the sintered body of Comparative Example 6 using a raw material in which the amount of BaTiO ₃ as an additive exceeds the range of the present invention (0.3 to 5.0) contains BaTiO ₃ as a main component. It can be seen that when the ceramic capacitor is fired, the capacitor adheres to the sintered body.

[0052]

As described above, according to the present invention, a zirconia material which has a small residual expansion during heat treatment, has excellent thermal shock resistance, can withstand long-term use, has good handling properties during use, and is inexpensive. Thus, it is possible to provide a heat treatment jig useful for heat treatment and heat baking of functional ceramics such as electronic components, or powders or compacts of various powder metallurgy.

Further, the present invention is made of inexpensive zirconia material having a small residual expansion during heat treatment, excellent thermal shock resistance, and improved mechanical strength, and is a functional ceramic for electronic parts and the like, or various powder metallurgy. And a heat treatment jig useful for heat treatment and heat baking of the powder or the molded article.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining evaluation of thermal shock resistance.

[Explanation of symbols]

 1 ... test piece, 2 ... holding table, 4 ... object to be fired.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Suzuki 1 Minami Fuji, Ogakie-cho, Kariya-shi, Aichi Prefecture Toshiba Ceramics Co., Ltd. Kariya Works

Claims (3)

[Claims] 1. 100 parts by weight of zirconia having a stabilization rate of 70 to 90% stabilized by solid solution of CaO
A heat treatment jig obtained by mixing 0.5 to 6.0 parts by weight of ₃ , mixing and firing, and made of zirconia having a high concentration range of Ca dispersed in grain boundaries. 2. 100 parts by weight of zirconia having a stabilization rate of 70 to 90% stabilized by solid solution of CaO
₃ to 0.5 to 6.0 parts by weight and Fe ₂ O ₃ to 0.3 to
A heat treatment jig obtained by mixing 5.0 parts by weight, molding and firing, and made of zirconia having a high concentration region of Ca and Fe dispersed in grain boundaries. 3. 100 parts by weight of zirconia having a stabilization rate of 70 to 90% stabilized by solid solution of CaO
₃ to 0.5 to 6.0 parts by weight and BaTiO ₃ to 0.3
A heat treatment jig obtained by mixing, shaping, and sintering a mixture of zirconia having a high concentration range of Ca, Ba, and Ti dispersed in grain boundaries.