JP2659082B2 - Manufacturing method of zirconia-based composite ceramic sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a zirconia-based composite ceramic sintered body suitable for, for example, structural materials.

[0002]

2. Description of the Related Art Polycrystalline ceramic sintered bodies have excellent heat resistance, abrasion resistance and corrosion resistance, and are therefore used in turbocharger rotors for automobile engines, various cutting tools, cutting tools, mechanical seals, sports and leisure goods, and the like. Is being used in a wide range of applications. However, ceramics inherently have strong covalent and ionic bonds and do not exhibit transition or plastic deformation, unlike metal materials, so that stress concentration at the tip of cracks cannot be relaxed and fine defects or surface damage in the material Easily breaks from the starting point. As described above, ceramics have low toughness and are very brittle, so they are not suitable as constituent materials for large-sized components or components having complicated shapes, and the shape and dimensions of molded products are naturally limited.

[0003] In order to improve the brittleness of the ceramic, attempts have been made to improve the toughness and strength by dispersing particles, whiskers and the like in the matrix of the ceramic sintered body to prevent cracks from developing. It has been done. Composite ceramics, which are pursued as an effective means of improving toughness, have been pursued from particle dispersion to whisker dispersion and fiber reinforcement, and from microcomposite, which combines the grain boundaries of polycrystalline ceramics, into grains. The transition to nanocomposites has become more complex. In particular, it has been reported that a nanocomposite material in which the crystal grain itself, which is the minimum structural unit of ceramic, is composited has a remarkable effect on increasing the strength and improving the strength in a high temperature range.

For example, in a system using an oxide ceramic as a matrix, Japanese Unexamined Patent Publication (Kokai) No. 64-87552 discloses an alumina sintered body obtained by compounding α-alumina matrix with SiC fine particles in a high strength and high temperature region. It is described that this is effective in improving the strength of steel. In addition, it is known that Al ₂ O ₃ / Si ₃ N ₄ and MgO / SiC nanocomposites exhibit high strength by the same method. Further, as an example of a system using a non-oxide ceramic as a matrix, "Powder and powder metallurgy, Vol. 36, p236 to p243
(1989)] [Si (CH) ₃ ] ₂ NH was converted to amorphous Si— by the CVD method in an atmosphere of ammonia and hydrogen.
It is reported that a composite powder of C—N is obtained, and a nanocomposite of Si ₃ N ₄ / SiC in which SiC particles are dispersed in Si ₃ N ₄ matrix particles using the composite powder as a starting material is strengthened. Have been.

[0005] Among these composite ceramic sintered bodies, the microcomposite material shows a fracture toughness value of about 10 MPam ^1/2 in a system composed of ZrO ₂ particles and whiskers. Fiber composite systems achieve high fracture toughness values as high as 20-30 MPam ^1/2 . However, the strength is limited to about 50 to 60% of that of the polycrystalline ceramic matrix alone, and further improvement in strength is desired.

On the other hand, in the nanocomposite material, although improvement in strength is recognized even in a high temperature range, improvement in toughness is about 30 to 40% of that of a polycrystalline ceramic matrix.
There is no significant contribution to toughness enhancement as in microcomposites.

As described above, further improvement in strength and toughness is expected in a polycrystalline ceramic composite material, and improvement in strength and toughness is also achieved in a partially stabilized zirconia sintered body to which CeO ₂ is added as a stabilizer. There is a need for a sintered body.

[0008]

THE INVENTION Problems to be Solved] The present invention, the zirconia-based composite ceramic sintered body having high strength and high toughness
The purpose is to provide a manufacturing method .

[0009]

[Means for Solving the Problems]The zircon of claim 1
The invention relating to the method for producing a near-type composite ceramic sintered body is disclosed in
eO _Two Stabilized zirconia mat containing 5 to 30 mol% of
The zirconia matte as a second phase in the Lix particles.
Has a melting point higher than the sintering temperature of _Two
O _Three , SiC, Si _Three N _Four Or B _Four C or periodic table
Carbides and nitrides of elements belonging to group IVa, Va, VIa
Or at least one selected from borides
And a relative density of 99%
The zirconia composite ceramic sintered body manufacturing method
Oh, CeO _Two Stabilized zircon containing 5 to 30 mol% of
Konia powder and Al _Two O _Three , SiC, Si _Three N _Four Young
Is B _Four C or element belonging to IVa, Va, VIa group of the periodic table
Selected from elementary carbides, nitrides or borides
An average particle diameter of at least 0.2 μm or more
The mixed powder containing fine particles having a particle diameter of 1 μm is
Lower than the melting point of fine particles having a diameter of 0.2 μm to 1 μm
Characterized by sintering at a temperature.The dice according to claim 2
Invention relating to a method for producing a luconia-based composite ceramic sintered body
Is obtained by using the mixed powder in the production method according to claim 1.
Embedded in the monoclinic zirconia powder
It is characterized by tying. The zirconia according to claim 3.
The invention relating to a method for producing a sintered ceramic composite is based on CeO.
_Two Stabilized zirconia matrix containing 5 to 30 mol% of
Zirconia matrix as a second phase in the silica particles.
Has a melting point higher than the sintering temperature of
_Two O _Three , SiC, Si _Three N _Four Or B _Four C or periodicity
Carbides and nitrides of elements belonging to groups IVa, Va and VIa in the table
Or at least one selected from borides
And a relative density of 99.
% Zirconia composite ceramic sintered body
And CeO _Two Stabilizing di-containing 5-30 mol% of
Luconia powder and γ-Al having an average particle size of 1 μm or less
_Two O _Three Sintering mixed powder containing powder
After calcining at a temperature below the temperature, calcined powder obtained by grinding
Γ-Al _Two O _Three Sintering at a temperature lower than the melting point of the powder
It is characterized by that.

Hereinafter, the present invention will be described in detail. Partially stabilized zirconia which constitutes the ceramic matrix in the present invention, it is important to contain CeO ₂ 5 to 30 mol%. Within this range, zirconia is mainly composed of tetragonal or a mixed phase of tetragonal and cubic,
It is preferable because high strength can be obtained. CeO ₂ is 5 mol%
If the amount is less than this, the metastable phase of tetragonal crystallization will be insufficient, and if it exceeds 30 mol%, the amount of cubic crystals will increase, and as a result, sufficient strength will not be obtained.

The method of obtaining partially stabilized zirconia powder using CeO ₂ as a stabilizer includes a method of mixing a stabilizer and zirconia powder, and a method of wet synthesis using an aqueous solution containing Ce and Zr. There is a method of obtaining a powder by a method. The partially stabilized zirconia powder of the present invention is sintered under normal pressure,
In order to be densified by pressure sintering or the like, and to incorporate the dispersed phase into particles of the matrix during the sintering process, the particles must grow during sintering. On the other hand, the fine particles dispersed in this matrix are limited to fine particles having a melting point higher than the sintering temperature of the matrix in order to be dispersed as fine particles after sintering. The present inventors have found that there are various metals as fine particles having such a high melting point.
Patent Application No. 6 has already been filed, but in addition to metal fine particles, Al ₂ O ₃ , SiC, Si ₃ N ₄ or B ₄
It has been found that fine particles comprising at least one selected from the group consisting of C, carbides, nitrides and borides of elements belonging to groups IVa, Va and VIa of the periodic table have the same effect as the fine particles of the metal. This is the invention.

The zirconia composite ceramic according to the present invention
The sintered body is in a partially stabilized zirconia matrix particle.
The sintering of the zirconia matrix as a second phase
It has a melting point higher than the temperature and Al ₂ O ₃ , SiC,
Si ₃ N ₄ or B ₄ C or IVa, Va,
Carbides, nitrides or borides of group VIa elements
Of fine particles consisting of at least one selected from
Sintering having a dispersed phase and a relative density of 99% or more
Body. The fine particles must be fine in order to be taken into the matrix particles during the sintering process, and the average particle size is desirably 1 μm or less. It is desirable that they are dispersed, but they may be partially present at the grain boundaries of the matrix. The addition amount of the dispersed phase of the fine particles to the partially stabilized zirconia constituting the ceramic matrix in the present invention is 0.5 to the total amount after addition.
50% by volume is desirable, and more preferably 2.5 to 30%.
% By volume. That is, when the dispersed phase is 2.5% by volume or less, the effect of improving the strength is small, and when the dispersed phase is 30% by volume or more, the densification becomes gradually difficult, and the strength gradually decreases. If the content exceeds 50% by volume, the relative density of the composite sintered body becomes 95% or less, and it becomes difficult to obtain a dense sintered body, and as a result, the strength is significantly deteriorated.

When the combination of the matrix and the dispersed phase is referred to in terms of the coefficient of thermal expansion, if the dispersed phase having a smaller coefficient of thermal expansion than the matrix is dispersed, it effectively contributes to the improvement of the toughness of the matrix. Although it is preferable in view of the point, it is not necessarily limited to this. The partially stabilized zirconia using the matrix of the present invention, CeO _2, as a stabilizer usually has a large coefficient of thermal expansion, and the dispersed phase shown above also satisfies the point that it has a smaller coefficient of thermal expansion than the matrix. .

Next, the mechanism of the effect of improving the toughness of the zirconia-based composite ceramic sintered body according to the present invention will be discussed.

The fine particles dispersed in the grains of the CeO ₂ -based partially stabilized zirconia ceramic constituting the matrix or partially in the grain boundaries have an action of suppressing the abnormal growth of the ceramic grains during the sintering process. As a result, the matrix is composed of a fine structure, resulting in a decrease in the size of the fracture source and a significant increase in strength. In addition, in the process of crack propagation by the fine particles dispersed in the ceramic matrix, the tip of the crack is curved (bowed) or deflected (deflection), thereby improving the toughness of the sintered body.

Further, CeO ₂ constituting the matrix
In a system in which the fine particles dispersed in the grains of the partially stabilized zirconia ceramic or at some grain boundaries have a smaller coefficient of thermal expansion than the ceramic constituting the matrix, the dispersed fine particles are more effective in improving the strength and toughness. Works. If the thermal expansion coefficients of the ceramic and the fine particles do not match, a residual stress field is formed in the matrix and around the fine particles during the cooling process after sintering, and this residual stress field affects the crack propagation path. give. That is, if the fine particles have a smaller coefficient of thermal expansion than the ceramic, a tensile stress is generated around the fine particles in the cooling process after sintering, and a residual tensile stress field is formed around the fine particles. It is attracted and consequently induces intragranular fracture of the ceramic. in this way,
Since the probability that the crack collides with the fine particles and increases is increased, the propagation of the crack is effectively prevented. At the same time, in the axial direction of the fine particles dispersed in the matrix, residual compressive stress is generated in the cooling process after sintering, and this greatly strengthens the ceramic crystal grains themselves, further improving the strength. It is achieved.

[0017] As method for obtaining a zirconia composite ceramic sintered body according to the present invention described above, according to claim 1 and
The production method according to the second aspect of the present invention is a method for producing a partially stabilized zirconia powder containing 5 to 30 mol% of CeO ₂ , Al ₂ O ₃ , Si
C, Si ₃ N ₄ or B ₄ C or IVa, V in the periodic table
a, a mixed powder comprising fine particles having an average particle diameter of 0.2 μm to 1 μm, which is made of at least one selected from carbides, nitrides or borides of elements belonging to Group VIa, The method is characterized in that it is sintered at a temperature lower than the melting point of the fine particles having a diameter of 0.2 μm to 1 μm. The mixed powder is prepared by blending a predetermined amount of a raw material powder, CeO ₂ -based partially stabilized zirconia powder, and fine particles having an average particle diameter of 0.2 μm to 1 μm, which is a dispersed phase, in ethanol, acetone, toluene, or the like. And then a wet ball mill mixing followed by drying.

In the production method according to the first and second aspects of the present invention, the mixed powder is molded into a desired shape by a conventional molding method such as a dry press or an injection molding method. Sintering is performed by vacuum sintering, gas pressure sintering, hot press sintering, hot isostatic pressing (HIP), or the like to obtain a densified sintered body. In addition, molding and sintering
It may be performed separately or simultaneously, and there is no limitation.

The atmosphere for sintering is as follows: raw material powder of partially stabilized zirconia, Al ₂ O ₃ , SiC, Si ₃ N ₄
And B ₄ C and the Periodic Table of the IVa, Va, the elements of the carbide belonging to Group VIa, to prevent oxidation of the nitrides and borides, vacuum, nitrogen gas, inert gas such as an argon gas atmosphere is suitable. In hot isostatic pressing sintering, a pre-sintered body with few open pores is prepared in advance by normal pressure sintering, hot pressing, etc. Any method can be applied, such as encapsulating by applying an airtight seal with glass or glass and subjecting this to hot isostatic pressing.

In the method for producing a zirconia-based composite ceramic sintered body according to the first aspect of the present invention, the compact obtained by using the mixed powder is embedded in monoclinic zirconia powder and sintered. It is desirable because a dense sintered body can be obtained. The method for obtaining the molded body in this case is not particularly limited, and the molded body may be formed into a desired shape by a dry press or an injection molding method. For sintering in this case, the obtained compact was embedded in monoclinic zirconia powder and inserted into a container that can withstand sintering conditions. Sintering may be performed. The monoclinic zirconia powder becomes a tetragonal zirconia powder which is a high-temperature stable phase in a temperature range of about 1170 ° C. or more and 2370 ° C. or less.
In a temperature range of 170 ° C. or less, the crystal is transformed into monoclinic zirconia, and has a property of exhibiting a volume expansion of about 4% during this transformation. Therefore, if the sintering performed in a state in which the compact is embedded in the monoclinic zirconia powder is performed at or above this crystal transformation temperature, pseudo hot isostatic pressing sintering (pseudo HIP sintering) is performed. An effect similar to that of hot isostatic pressing is achieved, and a denser sintered body can be obtained. Further, conventionally, CeO ₂ as a stabilizer is reduced in a reducing atmosphere such as a carbon atmosphere to produce CeO _2.
Tends to be ₂ O _3, Therefore, when sintered in a reducing atmosphere or a problem that the crystal phase after sintering hardly becomes tetragonal, since such problems sintered body cracking occurs, the reduction of carbon atmosphere moderate Sintering in an atmosphere was generally difficult, but if the compact was embedded in monoclinic zirconia powder and sintered, the carbon source such as a carbon heater was cut off during sintering. Therefore, there is an effect that the reduction of CeO ₂ can be suppressed and the problem associated with the conventional reduction of CeO ₂ can be improved.

According to a third aspect of the present invention, there is provided a method for producing a mixed powder comprising a partially stabilized zirconia powder containing 5 to 30 mol% of CeO ₂ and a γ-Al ₂ O ₃ powder having an average particle diameter of 1 μm or less. , After calcination at a temperature of 1000 ° C. or higher and a sintering temperature or lower, the calcined powder obtained by pulverization is sintered at a temperature lower than the melting point of γ-Al ₂ O ₃ powder. Has features. In the case of an alumina particle-dispersed composite ceramic sintered body, γ is used as a raw material for alumina particles as a dispersion species.
It is preferable to use -Al ₂ O ₃ powder because the primary particle diameter is very fine, but on the other hand, since it has a large specific surface area and is bulky, it can be formed by a conventional molding method (dry press method, injection molding method, etc.). There is a problem that it is difficult to give a desired shape. Therefore, such γ-Al ₂ O
_{3 When} examining the manufacturing method when using powder, C
A mixed powder containing a partially stabilized zirconia powder containing 5 to 30 mol% of eO ₂ and a γ-Al ₂ O ₃ powder was 1000
After calcination at a temperature of not less than ℃ and below the sintering temperature, if the calcined powder obtained by pulverization is sintered, it becomes possible to impart a desired shape by a common molding method, It has been found that a sintered body can be obtained. As the calcination temperature in this case, the γ-α transition temperature (about 1000
° C) or higher, and preferably 1300 ° C or lower from the viewpoint of facilitating pulverization after calcination.

[0022]

【Example】

(Examples 1 to 6 and Comparative Examples 1 and 2) β-SiC having an average particle size of 0.2 μm and a purity of 98% or more was added to a partially stabilized zirconia powder containing 5 to 35 mol% of CeO ₂ as shown in Table 1.
Was added to a polyethylene-coated iron ball and a polyethylene container and mixed in a wet ball mill for 24 hours using acetone as a solvent. The obtained powder was formed into a disc-shaped compact having a diameter of 60 mm and a thickness of 5 mm by a hydrostatic press, and a sintering temperature of 1600 ° C. in an argon atmosphere.
Sintering was performed under the conditions of a holding time of 2 hours.

These sintered bodies are dense with a relative density of 99% or more and a porosity of 1% or less.
In addition, observation with a transmission electron microscope confirmed that SiC fine particles were present in the partially stabilized zirconia grains.

Next, cutting from the disc-shaped sintered body,
By grinding, a sample of 4 × 3 × 35 mm was prepared.
The point bending strength was measured. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Table 1 shows the above measurement results.

The crystal phase of the sample was identified by X-ray diffraction, and the ratio of each phase was quantified. Table 1 shows the results.
The crystal phase of zirconia is shown in FIG. However, regarding the symbol of the crystal phase of zirconia, T is tetragonal, C is cubic, M
Represents a monoclinic crystal.

[0026]

[Table 1]

Examples 7 to 19: 12 mol% of CeO ₂
As shown in Tables 2 and 3, 5% by volume of various fine particles having an average particle size of 1 μm or less was added to the partially stabilized zirconia powder.
The resulting mixture was mixed in a wet ball mill for 24 hours using polyethylene coated iron balls and a polyethylene container with acetone as a solvent. However, in Table 3, when two types of fine particles are used, each type is 2.5% by volume, and the total amount is 5% by volume.
It was adjusted to become. Using a high-purity alumina mold, the obtained powder was sintered in an argon atmosphere at the sintering temperatures shown in Tables 2 and 3 for a holding time of 2 hours and a pressing pressure of 30 MPa.
Sintering was performed under the conditions of a to obtain a disc-shaped molded body having a diameter of 50 mm and a thickness of 4 mm.

These sintered bodies are dense with a relative density of 99% or more and a porosity of 1% or less.
And Table 2 and Table 3 by observation with a transmission electron microscope.
It was confirmed that the various fine particles shown in (1) existed in the partially stabilized zirconia particles. The crystal phase of zirconia was all tetragonal.

Next, cutting from the disc-shaped sintered body,
By grinding, a 4 × 3 × 35 mm sample was prepared, and the three-point bending strength of this sample at room temperature was measured according to JISR1601. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Tables 2 and 3 show the above measurement results.

[0030]

[Table 2]

[0031]

[Table 3]

(Comparative Examples 3 to 15) 12 mol% of CeO ₂
As shown in Tables 4 and 5, as the fine particles to be added to the partially stabilized zirconia powder containing, various kinds of fine particles having an average particle diameter exceeding 1 μm were used, and a disc-shaped molded body was obtained in the same manner as in Examples 7 to 19. Was.

Next, cutting from the disc-shaped sintered body,
By grinding, a 4 × 3 × 35 mm sample was prepared, and the three-point bending strength of this sample at room temperature was measured according to JISR1601. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Tables 4 and 5 show the above measurement results.

[0034]

[Table 4]

[0035]

[Table 5]

(Examples 20 to 25 and Comparative Examples 16 to 1)
7) β-Si having an average particle size of 0.2 μm and a purity of 98% or more was added to a partially stabilized zirconia powder containing 12 mol% of CeO _2.
As shown in Table 6, 0 to 60% by volume of fine particles of C was added to a wet ball mill for 24 hours using a polyethylene-coated iron ball and a polyethylene container with acetone as a solvent. The obtained powder was sintered using a high-purity alumina mold in an argon atmosphere at a sintering temperature of 1600 ° C., a holding time of 2 hours, and a pressing pressure of 30 MPa,
A disc-shaped sintered body having a diameter of 50 mm and a thickness of 4 mm was obtained.

In these sintered bodies, the amount of SiC added was 5
Those having 0% by volume or less have a relative density of 99% or more and a porosity of 1
% Or less, and it was confirmed by observation with a scanning electron microscope and a transmission electron microscope that SiC fine particles were present in the partially stabilized zirconia grains. However, when the added amount of SiC exceeds 30% by volume, the densification tends to gradually become difficult as the added amount increases,
At 60% by volume, the relative density was 95% or less.

Next, cutting from the disc-shaped sintered body,
By grinding, a 4 × 3 × 35 mm sample was prepared, and the three-point bending strength of this sample at room temperature was measured according to JISR1601. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Table 6 shows the above measurement results.

Using the numerical values shown in Table 6, the change in the three-point bending strength at room temperature with the change in the amount of SiC added is shown in FIG.
FIG. 2 shows the change in the fracture toughness value with the change in the amount of SiC added. When the content (% by volume) of SiC in the sintered body was examined, the content (% by volume) of SiC was determined.
And the amount (% by volume) of SiC added well. 1 and 2, the content (content) of SiC is 30% by volume.
Up to three-point bending strength,
Both the fracture toughness values were improved, and at 30 to 50% by volume, the three-point bending strength and the fracture toughness values showed a gradual decrease as the added amount (content) increased. And the addition amount (content) is 6
The three-point bending strength and fracture toughness at 0% by volume were lower than the three-point bending strength and fracture toughness of the partially stabilized zirconia alone.

[0040]

[Table 6]

(Examples 26 to 34) As shown in Table 7, 5% by volume of various fine particles having an average particle size of 1 μm or less was added to partially stabilized zirconia powder containing 12 mol% of CeO _2, which was made of polyethylene-coated iron. Using a ball and a polyethylene container, wet ball mill mixing was performed for 24 hours using acetone as a solvent. The obtained powder is pressed with a hydrostatic press to φ60.
Thus, a disk-shaped molded product having a thickness of 5 mm and a thickness of 5 mm was obtained. The obtained molded body was embedded in a high-purity alumina mold having an inner diameter of 65 mm together with a monoclinic zirconia powder having an average particle size of 2 μm, and in an argon atmosphere, at a sintering temperature shown in Table 7, at a holding time of 3 hours. Sintered below. In order to keep the container in the alumina container (alumina mold) during sintering constant, sintering was performed under the condition that a slight load (approximately 0.1 MPa) was applied to the upper punch. After cooling, the monoclinic zirconia was cooled. The sintered body was taken out from the powder.

The sintered bodies obtained in Examples 26 to 34 were dense with a relative density of 99% or more and a porosity of 1% or less, and were observed with a scanning electron microscope and a transmission electron microscope. It was confirmed that various fine particles shown in No. 7 were present in the partially stabilized zirconia grains. The crystal phase of zirconia in the obtained sintered body was all tetragonal.

Next, cutting from the disc-shaped sintered body,
By grinding, a 4 × 3 × 35 mm sample was prepared, and the three-point bending strength of this sample at room temperature was measured according to JISR1601. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Table 7 shows the above measurement results.

[0044]

[Table 7]

Example 35 A partially stabilized zirconia powder containing 12 mol% of CeO ₂ and 5 vol% of γ-Al ₂ O ₃ powder (fine particles) having a specific surface area of 300 m ² / g were added to polyethylene. Using a coated iron ball and a polyethylene container, wet ball mill mixing was performed for 24 hours using acetone as a solvent. The obtained mixed powder was calcined in the air at 1200 ° C. for 3 hours and then dry-pulverized for 24 hours using a zirconia ball and a zirconia container. Using the calcined powder thus obtained, a disk-shaped molded body having a diameter of 60 mm and a thickness of 5 mm was obtained by isostatic pressing. The obtained molded body was sintered in the atmosphere under the conditions of a sintering temperature of 1550 ° C. and a holding time of 3 hours. The obtained sintered body is
It is dense with a relative density of 99% or more and a porosity of 1% or less, and Al ₂ O ₃ fine particles are present in partially stabilized zirconia particles by observation with a scanning electron microscope and a transmission electron microscope. Was confirmed. The crystal phase of zirconia in the obtained sintered body was all tetragonal.

Next, cutting from the disc-shaped sintered body,
By grinding, a 4 × 3 × 35 mm sample was prepared, and the three-point bending strength of this sample at room temperature was measured according to JISR1601. The surface of the sample was polished to a mirror surface, and the fracture toughness value was measured by the SEPB method according to JISR1607. Table 8 shows the above measurement results.

(Comparative Example 18) In Comparative Example 18, a sintered body was obtained in the same manner as in Example 35 except that sintering was performed immediately without performing the calcination treatment in Example 35. .

A partially stabilized zirconia powder containing 12 mol% of CeO ₂ was added to γ-Al ₂ O having a specific surface area of 300 m ² / g.
_{3 A} powder to which 5% by volume of powder (fine particles) had been added was mixed in a wet ball mill for 24 hours using a polyethylene-coated iron ball and a polyethylene container with acetone as a solvent. The obtained mixed powder was immediately molded by an isostatic press without performing a calcination treatment, to obtain a disk-shaped molded body having a diameter of 60 mm and a thickness of 5 mm. The obtained molded body was sintered in air at a sintering temperature of 15
Sintering was performed at 50 ° C. for a holding time of 3 hours. The obtained sintered body had a relative density of 97% or less and was insufficiently densified.

After cutting and grinding from the obtained sintered body,
A 4 × 3 × 35 mm sample was prepared, and this sample was
The three-point bending strength at room temperature was measured by ISR1601. In addition, the surface of the sample is polished to a mirror surface and JISR1
The fracture toughness value was measured by the SEPB method according to 607.
Table 8 shows the above measurement results.

[0050]

[Table 8]

[0051]

EFFECT OF THE INVENTION Partially stable containing 5 to 30 mol% of CeO ₂
Zirconia powder and Al ₂ O ₃ , SiC, Si ₃ N ₄
Or B ₄ C or belongs to the IVa, Va, VIa group of the periodic table
Of carbides, nitrides or borides
Average particle size 0.2μ
a mixed powder containing fine particles having a particle size of
And sintering at a temperature lower than the melting point of the element.
According to the method for producing a zirconia-based composite ceramic sintered body described in 2 above
Zirconia-based composite cells with improved strength and toughness
A lamic sintered body can be manufactured. Claims
According to the method for producing a zirconia-based composite ceramic sintered body described in 3
Then, γ-Al ₂ O ₃ powder is used as a raw material for alumina particles.
Zirconia with improved strength and toughness even when used
A composite ceramic sintered body can be manufactured.

[0052]

[Brief description of the drawings]

FIG. 1 shows Examples 20 to 25 of the present invention and Comparative Examples 16 to 1.
7 is a graph showing the relationship between the amount of SiC added and the three-point bending strength at room temperature for the composite ceramic sintered body according to Example 7.

FIG. 2 shows Examples 20 to 25 of the present invention and Comparative Examples 16 to 1.
7 is a graph showing the relationship between the amount of SiC added and the fracture toughness value for the composite ceramic sintered body according to Example 7.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Niihara 9-7 Koriokaoka, Hirakata-shi, Osaka Kori Joint Dormitory 1142 (72) Inventor Atsushi Nakahira 1-2-3 Aoyamadai, Suita-shi, Osaka C33-307 No. (72) Inventor Toru Sekino 2-2-2341 Nishi Midorioka, Toyonaka-shi, Osaka (56) References JP-A-61-251568 (JP, A)

Claims (3)

(57) [Claims] 1. Partially stable containing 5 to 30 mol% of CeO ₂
In the zirconia matrix particles as a second phase
Melting point higher than the sintering temperature of the zirconia matrix
Al ₂ O ₃ , SiC, Si ₃ N ₄ or B
₄ C or the Periodic Table of the IVa, Va, of the elements belonging to Group VIa
Selected from among carbides, nitrides or borides
At least a dispersed phase of at least one kind of fine particles,
Zirconia composite ceramics with relative density of 99% or more
A method of click sintered body, the CeO ₂ 5 to 30 mol% free
Partially stabilized zirconia powder, Al ₂ O ₃ , SiC,
Si ₃ N ₄ or B ₄ C or IVa, Va,
Carbides, nitrides or borides of group VIa elements
Average grain consisting of at least one selected from among
Mixed powder containing fine particles having a diameter of 0.2 μm to 1 μm
Are fine particles having an average particle size of 0.2 μm to 1 μm.
Characterized by sintering at a temperature lower than the melting point of
A method for producing a konia-based composite ceramic sintered body. 2. A molded article obtained by using the above mixed powder.
Embedded in monoclinic zirconia powder and sintered.
The zirconia-based composite ceramic according to claim 1, wherein
Manufacturing method of sintered body. 3. Partially stable containing 5 to 30 mol% of CeO _2.
In the zirconia matrix particles as a second phase
Melting point higher than the sintering temperature of the zirconia matrix
Al ₂ O ₃ , SiC, Si ₃ N ₄ or B
₄ C or the Periodic Table of the IVa, Va, of the elements belonging to Group VIa
Selected from among carbides, nitrides or borides
At least a dispersed phase of at least one kind of fine particles,
Zirconia composite ceramics with relative density of 99% or more
A method of click sintered body, the CeO ₂ 5 to 30 mol% free
Partially stabilized zirconia powder with an average particle size of 1 μm or less
Γ-Al ₂ O ₃ powder,
After calcination at a temperature of 0 ° C or more and below the sintering temperature, pulverize
The obtained calcined powder is lower than the melting point of the γ-Al ₂ O ₃ powder.
Zirconia-based composite cell characterized by sintering at a
Manufacturing method of lamic sintered body.