JP2016216289A - Blue zirconia sintered body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blue zirconia sintered body comprising cobalt as a colorant, where the zirconia sintered body prevents color migration to a sintered member in the production process.SOLUTION: A zirconia sintered body comprises a complex oxide of cobalt and aluminum of 1-25 wt.%. Preferably, the complex oxide of cobalt and aluminum is cobalt aluminate, and the zirconia sintered body comprises at least one of iron, nickel and manganese.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a zirconia sintered body containing a coloring component. More specifically, the present invention relates to a zirconia sintered body exhibiting a blue color suitable for industrial production.

  A colored zirconia sintered body exhibiting a blue color (hereinafter also referred to as a “blue zirconia sintered body”) gives an impression of a high-class feeling. Therefore, application to high-grade building materials, mechanical members such as various structural members, ceramic electronic members such as electronic component boards, exterior members such as mobile phones and mobile home appliances, and the like is being studied.

  Conventionally, cobalt oxide has been used as a colorant for the production of a blue-colored zirconia sintered body. For example, a zirconia sintered body containing cobalt oxide and iron oxide has been reported as a blue zirconia sintered body (Patent Document 1).

  Furthermore, a zirconia sintered body having a blue color containing either chromium oxide or nickel oxide and aluminum oxide and cobalt oxide has been reported (Patent Document 2).

Japanese Patent Laid-Open No. 02-145475 Japanese Patent No. 5556292

  Cobalt becomes a colorant exhibiting a blue color, but easily diffuses during sintering. Phenomena in which members (hereinafter also referred to as “sintered members”) used during sintering, such as setters in a sintering furnace, are colored by the diffusion of cobalt when the blue zirconia sintered bodies of Patent Documents 1 and 2 are manufactured. So-called color transfer occurs. Therefore, when manufacturing the zirconia sintered compact of other colors using the sintered member used for manufacture of the blue zirconia sintered compact of patent documents 1 and 2, there is color transfer from a sintered member to a zirconia sintered compact. Arise. Therefore, such a sintered member can only be discarded or used as a sintered member exclusively for a blue zirconia sintered body.

  In view of the problem, an object of the present invention is to provide a zirconia sintered body which is a blue zirconia sintered body containing cobalt as a colorant and in which color transfer to a sintered member during production is suppressed. .

  The present inventors examined the sintering behavior and the colorant of the blue zirconia sintered body. As a result, it has been found that by using a complex oxide of cobalt as a colorant, the zirconia sintered body exhibits a blue color, and the color transfer to the sintered member is suppressed.

  That is, the present invention is a zirconia sintered body containing 1 to 25% by weight of a composite oxide of cobalt and aluminum.

  Hereinafter, the zirconia sintered body of the present invention will be described.

  The zirconia sintered body of the present invention contains a composite oxide of cobalt and aluminum (hereinafter also referred to as “Co—Al composite oxide”). By containing cobalt, the zirconia sintered body of the present invention exhibits a blue color tone. In addition to this, since cobalt is sintered as a Co—Al composite oxide, the diffusion of cobalt during sintering is suppressed, so that color migration is unlikely to occur. In addition, in a zirconia sintered body obtained by sintering cobalt oxide and aluminum oxide as colorants, cobalt oxide and aluminum oxide may become a partial composite oxide. However, such a zirconia sintered body is accompanied by the diffusion of cobalt during sintering, which causes color transfer.

The Co—Al composite oxide preferably has a spinel structure. Furthermore, the Co—Al composite oxide is preferably a composite oxide in which CoO: Al ₂ O ₃ is in a molar ratio of 0.9: 1.1 to 1.1: 0.9, and CoO: Al ₂ More preferably, it is a complex oxide in which O ₃ is 1: 1, and more preferably cobalt aluminate (CoAl ₂ O ₄ ). Cobalt aluminate contains cobalt and aluminum in a certain ratio and uniformly. By including cobalt aluminate, the zirconia sintered body of the present invention tends to have a uniform color tone without color unevenness.

  The content of the Co—Al composite oxide is 1% by weight or more, and further 2% by weight or more. When the Co—Al composite oxide is less than 1% by weight, the color tone of the zirconia sintered body becomes too thin. In order to exhibit a clearer blue color, the content of the Co—Al composite oxide is preferably 3% by weight or more, more preferably 4% by weight or more, and even more preferably 4.5% by weight or more. On the other hand, the content of the Co—Al composite oxide is 25% by weight or less, further 20% by weight or less, and further 15% by weight or less. When the Co-Al composite oxide exceeds 25% by weight, excessive Co-Al composite oxide is precipitated during sintering, causing color transfer, and the density of the sintered body tends to decrease. In order to further suppress color transfer, the Co—Al composite oxide is preferably 10% by weight or less, and more preferably 7% by weight or less.

In the present invention, the content of the Co—Al composite oxide is the ratio of the weight of cobalt (Co) and aluminum (Al) in terms of oxide to the weight of the zirconia sintered body. Cobalt oxide conversion may be cobalt oxide (CoO), and aluminum oxide conversion may be aluminum oxide (Al ₂ O ₃ ).

  The zirconia sintered body of the present invention preferably contains one or more members selected from the group consisting of iron, nickel, and manganese, and more preferably contains at least one of iron and manganese. Thereby, the color tone of the zirconia sintered body of the present invention becomes dark blue and can be used for applications where a higher-class feeling is required.

  When the content of the toning component is larger than the content of the Co—Al composite oxide, the color tone of the toning component tends to be strong. Therefore, the content of the toning component in terms of oxide with respect to the content of the Co—Al composite oxide is preferably 100% or less by weight, 50% or less, further 20% or less, and further 17 % Or less, and further preferably 12% or less.

  In order to make the zirconia sintered body of the present invention a zirconia sintered body exhibiting a dark blue color (hereinafter also referred to as “dark blue zirconia sintered body”), one or more members of the group consisting of iron, nickel and manganese (Hereinafter also referred to as “toning component”) is preferably 0.05% by weight or more, and more preferably 0.1% by weight or more. The content of the toning component may be equal to or less than the content of the Co-Al composite oxide, but the content of the toning component is 8% by weight or less, further 6% by weight or less, and further 1% by weight or less. Furthermore, it is 0.8% by weight or less, and further 0.5% by weight or less. Furthermore, when the toning component is only iron, the content is preferably 0.05% by weight or more and 1.2% by weight or less, more preferably 0.08% by weight or more and 0.2% by weight or less. Similarly, when the toning component is only nickel, the content is preferably 0.05% by weight to 1% by weight, and more preferably 0.2% by weight to 0.5% by weight. When the component is only manganese, the content is preferably 0.1% by weight or more and 1% by weight or less, more preferably 0.4% by weight or more and 0.7% by weight or less.

In the present invention, the content of the toning component is the ratio of the weight of iron (Fe), nickel (Ni), and manganese (Mn) in terms of oxide to the weight of the zirconia sintered body. As for the oxide conversion of each toning component, iron may be iron oxide (Fe ₂ O ₃ ), nickel may be nickel oxide (NiO), and manganese may be manganese oxide (Mn ₃ O ₄ ).

  If the zirconia sintered body of the present invention contains a Co-Al composite oxide and a toning component, the zirconia sintered body exhibits a blue color, and the color transfer to the sintered member during sintering is suppressed. Is done. On the other hand, the zirconia sintered body of the present invention may contain cobalt oxide as long as color transfer hardly occurs. As content of such cobalt oxide, the amount smaller than cobalt in Co-Al complex oxide can be mentioned.

When the zirconia sintered body of the present invention contains cobalt oxide (CoO), the cobalt oxide content is the cobalt content in the cobalt oxide relative to the total content of cobalt in the sintered body (hereinafter referred to as “CoO / Co _Total”). ")") Is 0.2 or less, and further 0.1 or less in terms of oxide. Co ₃ O ₄ is black. Therefore, it is preferable that the zirconia sintered body of the present invention does not contain Co ₃ O ₄ . Zirconia sintered body _Co 3 _{O 4} containing and have not the XRD powder X-ray diffraction of the present invention (hereinafter, referred to as "XRD".) No XRD peak corresponding to _Co 3 _{O 4} in the pattern and manufacturing This can be confirmed from the fact that sometimes Co ₃ O ₄ is not used as a raw material.

Moreover, the zirconia sintered body of the present invention may contain aluminum oxide (Al ₂ O ₃ ).

  The zirconia sintered body of the present invention preferably contains a stabilizer. The stabilizer is preferably one that does not affect the color tone of zirconia, and can include yttria. The amount of the stabilizer may be 2 mol% or more and 4 mol% or less, further 2.5 mol% or more and 3.5 mol% or less, and more preferably 2.8 mol% or more and 3.2 mol% or less. The crystal phase of the zirconia sintered body of the present invention is preferably tetragonal.

The zirconia sintered body of the present invention exhibits a blue color. This color tone is L ^* , a ^*, and b ^* in the L ^* a ^* b ^* color system (hereinafter also simply referred to as “L ^* ”, “a ^* ”, and “b ^* ”), respectively, 5 ≦ L ^* ≦ 30, −10 ≦ a ^* ≦ 15 and −60 ≦ b ^* ≦ 0, and further 5 ≦ L ^* ≦ 25, −8 ≦ a ^* ≦ 13 and −50 ≦ b ^* ≦ −3 There are some. In order to obtain a clearer blue zirconia sintered body, it is preferable that 5 ≦ L ^* ≦ 23, −8 ≦ a ^* ≦ 13, and −48 ≦ b ^* ≦ −4. Furthermore, in order to obtain a dark blue zirconia sintered body, 7 ≦ L ^* ≦ 20, −8 ≦ a ^* ≦ 8 and −35 ≦ b ^* ≦ −4, and further 7 ≦ L ^* ≦ 19, −8 ≦ a ^*. It is preferable that ≦ 8 and −30 ≦ b ^* ≦ −4, and further 7.5 ≦ L ^* ≦ 18, −7 ≦ a ^* ≦ 8, and −30 ≦ b ^* ≦ −4.5.

In the present invention, L ^* , a ^* and b ^* are the color tones measured from the surface reflected light of the sintered body, and are different from the color tones measured from the transmitted light and the reflected light.

  The higher the strength of the zirconia sintered body of the present invention, the more uses for which it can be applied. Therefore, the zirconia sintered body of the present invention preferably has a three-point bending strength of 900 MPa or more, more preferably 1000 MPa or more, and even more preferably 1100 MPa or more.

  Next, the manufacturing method of the zirconia sintered compact of this invention is demonstrated.

  The zirconia sintered body of the present invention can be obtained by any method as long as it contains at least one or more of the group consisting of iron, nickel and manganese and a complex oxide of cobalt and aluminum. As a preferred production method, a mixing step of obtaining a mixed powder by mixing 1% by weight or more and 25% by weight or less of a complex oxide of cobalt and aluminum with a zirconia powder, a forming step of forming a mixed powder to obtain a molded body, The manufacturing method which has the baking process which bakes a molded object can be mentioned.

The composite oxide of cobalt and aluminum (Co—Al composite oxide) used for the mixing step is preferably a composite oxide having a spinel structure. Furthermore, the Co—Al composite oxide is preferably a composite oxide in which CoO: Al ₂ O ₃ is in a molar ratio of 0.9: 1.1 to 1.1: 0.9, and CoO: Al ₂ More preferably, O ₃ is a complex oxide having a molar ratio of 1: 1, and cobalt aluminate (CoAl ₂ O ₄ ) is particularly preferable. Cobalt aluminate contains cobalt and aluminum in a certain ratio and uniformly. By including cobalt aluminate, the obtained zirconia sintered body tends to have a uniform color tone without color unevenness.

  The Co—Al composite oxide is 1% by weight or more, and further 2% by weight or more. In order to obtain a sintered body exhibiting a clearer blue color, the Co—Al composite oxide is preferably 3 wt% or more, more preferably 4 wt% or more, and even more preferably 4.5 wt% or more. On the other hand, the Co—Al composite oxide is 25% by weight or less, further 20% by weight or less, and further 15% by weight or less. When the Co-Al composite oxide exceeds 25% by weight, excessive Co-Al composite oxide is precipitated during sintering, causing color transfer, and the density of the obtained sintered body tends to decrease. In order to further suppress color transfer, the Co—Al composite oxide is preferably 10% by weight or less, and more preferably 7% by weight or less.

The zirconia powder to be subjected to the mixing step is a zirconia powder containing a stabilizer, further yttria-containing zirconia, or further zirconia powder containing 2 mol% to 4 mol% yttria, and further 2.5 mol% to 3.5 mol%. Zirconia powder containing the following yttria, or zirconia powder containing 2.8 mol% or more and 3.2 mol% or less yttria is preferable. The BET specific surface area is preferably a powder of 6 m ² / g or more and 15 m ² / g or less.

  In order to easily reproduce the color tone of the obtained zirconia sintered body, it is preferable that impurities other than zirconia and a stabilizer are 0.6% by weight or less, and further 0.5% by weight or less.

  In the mixing step, it is preferable to mix a compound containing at least one member (toning component) of the group consisting of iron, nickel and manganese, and it is more preferable to mix a compound containing at least one of iron and nickel. Thereby, the color tone of the obtained zirconia sintered body becomes dark blue, and can be used for applications where a higher-class feeling is required.

  The compound containing the toning component is at least one selected from the group consisting of oxides, hydroxides, oxyhydroxides, sulfates, nitrates, chlorides and acetates of the toning components, and further the oxide of the toning components Can be mentioned.

  The weight ratio of the compound containing the toning component to the Co—Al composite oxide is preferably 100% or less, 50% or less, more preferably 20% or less, further 17% or less, or even 12% or less. It is preferable that

  In order to make the obtained sintered body a dark blue zirconia sintered body, the compound containing the toning component is preferably mixed in an amount of 0.05% by weight or more, more preferably 0.1% by weight or more. The oxide containing the toning component is 8% by weight or less, further 6% by weight or less, further 1.0% by weight or less, further 0.8% by weight or less, and further 0.5% by weight or less. Mixing may be mentioned.

  In the production method of the present invention, it is preferable not to contain cobalt oxide, but in the mixing step, cobalt oxide or aluminum oxide may be mixed as necessary. When cobalt oxide is mixed, the amount of cobalt oxide mixed is such that the ratio of the amount of cobalt mixed in cobalt oxide to the total content of cobalt in the mixed powder is 0.2 or less, further 0.1 or less in terms of oxide. It is mentioned that.

  What is necessary is just to mix so that the composition of the obtained mixture may become uniform. Since the resulting mixture becomes more uniform, the mixing method is preferably wet mixing, and more preferably wet mixing using a ball mill. As a more specific mixing method, 30% by weight or more, further 45% by weight of water with respect to the weight of the mixture is mixed with the mixture to form a slurry, and the average particle size of the mixture in the slurry is 1 μm or less, Furthermore, wet mixing is mentioned so that it may become 0.6 micrometer or less. The average particle size of the mixture is not particularly limited as long as the aggregation of the mixture is moderately suppressed when dried, and may be 0.1 μm or more.

  In the forming step, the mixture obtained in the mixing step is formed. The method is arbitrary as long as a molded body having a desired shape is obtained. Examples of the molding method include at least one selected from the group consisting of press molding, cold isostatic pressing, sheet molding, injection molding, and cast molding.

  When wet mixing is applied in the mixing step, the mixture may be appropriately dried prior to the forming step. Examples of drying conditions include drying at 100 to 120 ° C. in the air.

  In the sintering process, the molded body obtained in the molding process is sintered. Any method can be applied as the sintering method. As a sintering method, at least one of normal pressure sintering and pressure sintering can be mentioned. Since the zirconia sintered body of the present invention can be easily obtained, the sintering process is preferably atmospheric pressure sintering. Here, the normal pressure sintering is a method of sintering by simply heating without applying an external force to the compact during sintering.

  The sintering temperature may be any temperature at which the sintering of zirconia proceeds, and examples include 1300 ° C. or higher and 1600 ° C. or lower. Examples of the sintering atmosphere include at least one selected from the group consisting of an oxidizing atmosphere, an inert atmosphere, and a reducing atmosphere, and an oxidizing atmosphere. Since sintering can be performed with simple sintering equipment, the sintering atmosphere is preferably in the air.

  As a particularly preferable firing step, atmospheric pressure sintering at 1450 ° C. or higher and 1550 ° C. or lower can be cited in the air.

  According to the present invention, it is possible to provide a zirconia sintered body containing cobalt and exhibiting a deep blue color, in which color transfer to a sintered member during production is suppressed.

Analysis result of cobalt by SEM-EPMA in Example 16 Overview of sintered member after sintering of Example 6 Overview of sintered member after sintering of Comparative Example 1 Analysis result of cobalt by SEM-EPMA in Comparative Example 1

Hereinafter, the present invention will be specifically described. However, the present invention is not limited to these examples.
(Measurement of color tone)
The color tone of the sintered body was measured using a color difference meter (device name: Z-300 type, manufactured by Nippon Denshoku Co., Ltd.). A D65 light source was used as a light source, and L ^* , a ^* and b ^* of the sample were measured from the reflected light from the sample surface under the condition of a viewing angle of 10 degrees.

As a measurement sample, a sintered body sample was ground and then polished using 3 μm diamond abrasive grains.
(3-point bending strength)
The bending strength of the sintered body was measured using an autograph (apparatus name: AGS-5kNX, manufactured by Shimadzu Corporation) according to JIS1601.

Example 1
3 mol% yttria-containing zirconia having an average particle diameter of 0.4 μm so that CoAl ₂ O ₄ is 2.0 wt%, Fe ₂ O ₃ is 0.2 wt%, and the balance is 3 mol% Y ₂ O ₃ -containing ZrO _2. The powder, cobalt aluminate powder having an average particle size of 0.5 μm, and iron oxide powder having an average particle size of 0.6 μm were mixed to obtain a mixed powder.

  After adding the same amount of pure water as the obtained mixed powder to make a slurry, the slurry is pulverized and mixed by a ball mill using zirconia balls having a diameter of 10 mm to obtain a mixed slurry having an average particle size of 0.5 μm or less. It was. The mixed slurry was dried in air at 110 ° C. for 2 hours to obtain a dry powder.

The obtained dry powder was uniaxially press-molded at 700 kg / cm ² to form a disk-shaped molded body having a diameter of 25 mm, and this was formed on an alumina sintered member (hereinafter also simply referred to as “sintered member”). Arranged. The molded body was sintered in the atmosphere at 1500 ° C. for 2 hours while being placed on the sintered member to obtain a zirconia sintered body of this example. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 2
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 2.0 wt%, Fe ₂ O ₃ was 0.4 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 3
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 3.3 wt%, Fe ₂ O ₃ was 0.1 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 4
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 3.5 wt%, Fe ₂ O ₃ was 0.15 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small. The three-point bending strength was 1314 MPa.

Example 5
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 4.0 wt%, Fe ₂ O ₃ was 0.2 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 6
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 5.0 wt%, Fe ₂ O ₃ was 0.1 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness. The results are shown in Table 1.

  The appearance of the sintered member after sintering is shown in FIG. Although the surface where the sintered member and the sintered body were in contact with each other was faintly discolored, almost no color transfer to the sintered member was confirmed.

Example 7
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 6.0 wt%, Fe ₂ O ₃ was 0.8 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 8
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 6.0 wt%, Fe ₂ O ₃ was 1.0 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 9
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 10.0 wt%, Fe ₂ O ₃ was 0.4 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body exhibited a uniform dark blue color with no color unevenness, and there was little color transfer to the sintered member used for its production.

Example 10
Example 1 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 15.0 wt%, Fe ₂ O ₃ was 0.6 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and there was little color transfer to the sintered member used for its production.

Example 11
Nickel oxide with an average particle size of 0.6 μm so that the composition of the mixed powder is 5.0% by weight of CoAl ₂ O ₄ , 0.2% by weight of NiO, and the balance is ZrO ₂ containing ₃ mol% Y ₂ O ₃ A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that powder was used. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 12
The composition of the mixed powder was the same as in Example 11 except that CoAl ₂ O ₄ was 5.0 wt%, NiO was 0.5 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained by the method. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 13
The composition of the mixed powder was the same as that of Example 11 except that CoAl ₂ O ₄ was 5.0 wt%, NiO was 0.8 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained by the method. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 14
The composition of the mixed powder was such that the average particle size was 0.8 μm so that CoAl ₂ O ₄ was 5.0 wt%, Mn ₃ O ₄ was 0.2 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that this manganese oxide powder was used. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 15
Example 14 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 5.0 wt%, Mn ₃ O ₄ was 0.6 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 16
Example 14 except that the composition of the mixed powder was such that CoAl ₂ O ₄ was 6.0 wt%, Mn ₃ O ₄ was 0.6 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as described above. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

  Moreover, the result of SEM-EPMA is shown in FIG. From FIG. 2, it was confirmed that the zirconia sintered body of this example had no aggregation of cobalt.

Example 17
The composition of the mixed powder is such that CoAl ₂ O ₄ is 5.0 wt%, NiO is 0.05 wt%, Mn ₃ O ₄ is 0.5 wt%, and the balance is 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that nickel oxide powder having an average particle size of 0.6 μm and manganese oxide powder having an average particle size of 0.8 μm were used. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small. The three-point bending strength was 1206 MPa.

Example 18
The composition of the mixed powder is such that CoAl ₂ O ₄ is 5.0 wt%, NiO is 0.2 wt%, Mn ₃ O ₄ is 0.4 wt%, and the balance is 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this example was obtained in the same manner as in Example 17 except that it was changed. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 19
The composition of the mixed powder is as follows: CoAl ₂ O ₄ is 5.0% by weight, NiO is 0.2% by weight, Mn ₃ O ₄ is 0.6% by weight, Al ₂ O ₃ is 1.5% by weight, and the balance is 3 mol. A zirconia sintered body of this example was obtained in the same manner as in Example 17 except that aluminum oxide powder having an average particle diameter of 0.4 μm was used so as to obtain% Y ₂ O ₃ -containing ZrO ₂ . The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform and clear blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Example 20
The composition of the mixed powder was such that CoAl ₂ O ₄ was 12.5 wt%, Fe ₂ O ₃ was 0.5 wt%, CoO was 0.6 wt%, and the balance was ZrO ₂ containing ₃ mol% Y ₂ O _3. In addition, a zirconia sintered body of this example was obtained in the same manner as in Example 1 except that cobalt oxide powder having an average particle diameter of 0.9 μm was used. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform deep dark blue color with no color unevenness, and the color transfer to the sintered member used for its production was slightly more.

Example 21
The composition of the mixed powder was the same as in Example 1 except that CoAl ₂ O ₄ was 2% by weight and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A ligature was obtained. The results are shown in Table 1.

  The obtained zirconia sintered body had a uniform blue color with no color unevenness, and the color transfer to the sintered member used for the production was very small.

Comparative Example 1
Average particles so that Al ₂ O ₃ is 5.0 wt%, CoO is 1.9 wt%, Fe ₂ O ₃ is 0.50 wt%, and the balance is 3 mol% Y ₂ O ₃ containing ZrO _2. 3 mol% yttria-containing zirconia powder having a diameter of 0.4 μm, aluminum oxide powder having an average particle diameter of 0.4 μm, iron oxide having an average particle diameter of 0.6 m, and cobalt oxide powder having an average particle diameter of 0.5 μm are mixed. To obtain a mixed powder.

  After adding the same amount of pure water as the obtained mixed powder to make a slurry, the slurry was pulverized and mixed by a ball mill using zirconia balls having a diameter of 10 mm to obtain a mixed slurry having an average particle size of 0.5 μm or less. . After pulverization and mixing, it was dried in the atmosphere at 110 ° C. for 2 hours.

After drying, uniaxial press molding was performed at 700 kg / cm ² to obtain a plate-shaped molded body, which was placed on an alumina sintered member. The molded body was sintered in the atmosphere at 1500 ° C. for 2 hours in a state of being placed on the sintered member to obtain a zirconia sintered body of this comparative example. The results are shown in Table 2.

  After sintering, the portion of the sintered member in contact with the sintered body was discolored blue, and it was confirmed that the colorant from the zirconia sintered body was diffused into the sintered member. The sintered member after sintering is shown in FIG. From FIG. 3, it was confirmed that the sintered member was colored so as to follow the outline of the disc-shaped zirconia sintered body.

  The zirconia sintered body had a blue color as a whole, but had color unevenness. The result of SEM-EPMA of the zirconia sintered body of this comparative example is shown in FIG. FIG. 4 shows a non-uniform distribution, and it was confirmed that cobalt was aggregated and unevenly distributed in the zirconia sintered body of this comparative example as compared with the zirconia sintered body of the example.

Comparative Example 2
According to the method of Patent Document 2, a blue zirconia sintered body was produced. That is, the composition of the mixed powder was such that Al ₂ O ₃ was 3.0 wt%, CoO was 2.1 wt%, Fe ₂ O ₃ was 0.10 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO. except that was made to be ₂ in the same manner as in Comparative example 1 method, to obtain a zirconia sintered body of the present comparative example. The results are shown in Table 2.

  After sintering, the portion of the sintered member in contact with the sintered body was discolored blue, and it was confirmed that the sintered member was impregnated with the colorant from the zirconia sintered body. From this, it turned out that the diffusion of cobalt is larger in this comparative example than in the zirconia sintered body of this example.

Comparative Example 3
Comparative Example 1 except that the composition of the mixed powder was such that Al ₂ O ₃ was 15.0 wt%, CoO was 2.0 wt%, and the balance was 3 mol% Y ₂ O ₃ containing ZrO _2. A zirconia sintered body of this comparative example was obtained in the same manner. The results are shown in Table 2.

  After sintering, the portion of the sintered member in contact with the sintered body was discolored blue, and it was confirmed that the sintered member was impregnated with the colorant from the zirconia sintered body.

  In Tables 1 and 2, the color transfer indicates that “◎” is very small, “◯” is small, “Δ” is slightly large, and “×” is very large.

  The zirconia sintered body according to the present invention can be used as a member containing the zirconia sintered body, in particular, high-grade building materials, mechanical members such as various structural members, ceramic electronic members such as electronic component substrates, mobile phones, mobile home appliances, and the like. It can be applied as a member or the like.

Claims (8)

  A zirconia sintered body characterized by containing a composite oxide of cobalt and aluminum in an amount of 1% by weight to 25% by weight.   The zirconia sintered body according to claim 1, wherein the complex oxide of cobalt and aluminum is cobalt aluminate.   The zirconia sintered body according to claim 1 or 2, comprising at least one member of the group consisting of iron, nickel and manganese.   The zirconia sintering according to claim 3, wherein the content of at least one of the group consisting of iron, nickel and manganese in terms of oxide is 100% or less by weight with respect to the content of the composite oxide of cobalt and aluminum. body. L ^* a ^* b ^{* L} in color system *, ^{a *} and ^{b *,} 5 ≦ ^{L *} ≦ 30, of claims 1 to 4 is -10 ≦ ^{a *} ≦ 15 and -60 ≦ ^{b *} ≦ 0 The zirconia sintered body according to any one of the above.   Mixing step of mixing 1% by weight to 25% by weight of cobalt and aluminum composite oxide with zirconia powder to obtain a mixed powder, molding step of molding the mixed powder to obtain a molded body, and firing the molded body The manufacturing method of the zirconia sintered compact as described in any one of Claims 1 thru | or 5 which has a baking process.   The manufacturing method according to claim 6, wherein in the mixing step, a compound containing one or more members of the group consisting of iron, nickel, and manganese is mixed.   The member containing the zirconia sintered compact as described in any one of Claims 1 thru | or 5.

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