JP6658050B2 - Colored zirconia sintered body - Google Patents

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 having a purple color tone.

  Colored zirconia sintered bodies are used for decorative members such as watch bands and accessories because they have both high mechanical strength and high aesthetics. Further, recently, in addition to these uses, application to high-grade building materials, mechanical members such as various structural members, ceramic electronic members such as electronic component substrates, and exterior members such as mobile phones and mobile home electric appliances has been studied.

  As one of the colored zirconia sintered bodies, a colored zirconia sintered body that exhibits purple as an intermediate color tone from red to blue has been studied.

For example, it has been reported that a zirconia sintered body containing one of erbium oxide, europium oxide and holmium oxide and a zirconia sintered body containing zinc oxide and aluminum oxide exhibits a purple color (Patent Document 1). Further, it is disclosed that a zirconia-alumina composite oxide containing Nd ₂ O ₃ or CoO exhibits a light purple color (Patent Document 2).

Further, it is disclosed that a zirconia sintered body containing V ₂ O ₅ and Al ₂ O ₃ exhibits a purple color (Patent Document 3).

Furthermore, it has been disclosed that ZrO ₂ containing erbium oxide and a stabilizer gives a pale pink white color (Patent Document 4).

International Publication No. 2009/157508 JP-A-01-234364 JP-A-01-157462 JP-A-04-002658

  The zirconia sintered body disclosed in Patent Literature 1 is a zirconia sintered body having a color tone close to gray, and has a color tone different from a so-called purple color. Further, the zirconia sintered bodies of Patent Documents 2 and 3 also have a color tone close to gray, and can be manufactured only by HIP processing. The sintered body that was not subjected to the HIP treatment had a color tone significantly different from purple. Patent Literature 4 is a zirconia sintered body that exhibits a pink color or a light pink color, and exhibits a color tone different from purple.

  An object of the present invention is to provide a purple zirconia sintered body suitable for industrial production.

  The present inventors have studied the above problem. As a result, a zirconia sintered body mainly containing a composite oxide of cobalt and aluminum and erbium oxide as a coloring agent, and further containing zinc and aluminum at a certain ratio, exhibits a purple color tone, and It has been found that it can be obtained stably.

  That is, the present invention contains a composite oxide of cobalt and aluminum, erbium oxide, zinc oxide, aluminum oxide and zirconia, and the total content of cobalt, aluminum and zinc is 5% by weight or less in terms of oxide. The zirconia sintered body has a weight ratio of zinc to aluminum of less than 0.9 in terms of oxide.

  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, zinc oxide, aluminum oxide, and erbium oxide (hereinafter, these may be individually or collectively referred to as “colored oxide”). Cobalt, aluminum, zinc and erbium in the zirconia sintered body function as coloring agents. By containing these four different colored oxides, the zirconia sintered body of the present invention exhibits a purple color, and further, a reddish and bluish purple color.

  In the zirconia sintered body of the present invention, the total content of the colored oxides may be not more than 20% by weight, more preferably not more than 15% by weight. A zirconia sintered body exhibiting a purple color can be obtained by using the colored oxide and the content. In addition to this, the reproducibility of the color tone is also increased in repeated production, especially in repeated production under normal pressure sintering. In order to make the coloration clear, the total content of the colored oxides is preferably 5% by weight or more, more preferably 7% by weight or more.

The content of the colored oxide in the zirconia sintered body of the present invention is a weight ratio of each colored oxide to the weight of the zirconia sintered body. The content of each colored oxide is as follows: CoAl ₂ O ₄ , CoO _{2 as} cobalt oxide, CoO as cobalt oxide, Al ₂ O _{3 as} aluminum oxide, Er ₂ O _{3 as} erbium oxide, and ZnO as zinc oxide. Should be obtained.

  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 the Co-Al composite oxide and erbium oxide, the zirconia sintered body of the present invention exhibits a purple color tone.

The Co—Al composite oxide is preferably a Co—Al composite oxide having a spinel structure, and more preferably cobalt aluminate (CoAl ₂ O ₄ ). Cobalt aluminate contains a certain ratio of cobalt and aluminum uniformly. Thereby, the zirconia sintered body of the present invention exhibits a uniform color tone. On the other hand, in a zirconia sintered body containing cobalt oxide and aluminum oxide as their respective oxides, the distribution of cobalt and aluminum in the sintered body tends to be uneven. As a result, color unevenness tends to occur in the sintered body. In particular, cobalt oxide as a single substance exhibits a color tone different from that of the Co—Al composite oxide, and conspicuous color unevenness is likely to occur. Therefore, it is preferable that the zirconia sintered body of the present invention does not contain cobalt oxide that does not form a composite oxide with aluminum, and further does not contain cobalt oxide, or further contains CoO and Co ₃ O ₄ .

The color tone of the zirconia sintered body of the present invention is mainly affected by the content of the Co—Al composite oxide and the content of erbium oxide. Therefore, the preferable content of the Co—Al composite oxide differs depending on the content of erbium oxide. The content of the Co—Al composite oxide is 0.01% by weight or more and 1% by weight or less, more preferably 0.01% by weight or more and 0.3% by weight or less when converted as an oxide (CoAl ₂ O ₄ ). Further, the content is 0.05% by weight or more and 0.3% by weight or less.

  The zirconia sintered body of the present invention contains erbium oxide. By containing the Co-Al composite oxide and erbium oxide, it exhibits a purplish color tone. In addition, erbium oxide has a function as a stabilizer for zirconia. The content of erbium oxide is preferably at least 5% by weight, more preferably at least 7% by weight. Thereby, the zirconia sintered body of the present invention can exhibit a bright purple color. On the other hand, erbium oxide is preferably 15% by weight or less, more preferably 13% by weight or less, and further preferably 9% by weight or less.

  Erbium oxide may be contained in a state of solid solution in zirconia or in an oxide state. Since color unevenness in the sintered body is less likely to occur, it is preferable that erbium oxide is in a solid solution state with zirconia, that is, zirconia is erbium oxide-containing zirconia.

  Whether or not erbium oxide is dissolved in zirconia can be confirmed by a powder X-ray diffraction (hereinafter referred to as “XRD”) pattern of the zirconia sintered body. That is, when erbium oxide is dissolved in zirconia, no independent XRD peak of erbium oxide is observed in the XRD pattern.

The zirconia sintered body of the present invention contains aluminum oxide and zinc oxide. By containing aluminum oxide and zinc oxide in addition to the Co-Al composite oxide, it is possible to control the lightness L ^* and the chromaticity b ^* of the zirconia sintered body of the present invention, and A purple tone can be obtained with high reproducibility in repeated production by pressure sintering.

  Furthermore, the zirconia sintered body of the present invention has a weight ratio of zinc to aluminum (hereinafter, also referred to as “Zn / Al ratio”) of less than 0.9, and more preferably 0.89 or less in terms of oxide. When the Zn / Al ratio increases, the color tone becomes too yellow and the purple color tone becomes weaker. Further, when the Zn / Al ratio exceeds 1.2, the sintered body is easily cracked during sintering. In order to obtain a sintered body exhibiting a bright purple color with good reproducibility, the Zn / Al ratio is preferably 0.15 or more, more preferably 0.19 or more. A preferable range of the Zn / Al ratio is 0.15 or more and less than 0.9, furthermore, 0.15 or more and 0.89 or less, further 0.25 or more and 0.85 or less, or even 0.35 or more. 6 or less.

  The content of zinc oxide and aluminum oxide in the zirconia sintered body of the present invention may be any content as long as the Zn / Al ratio is within the above range. The content of zinc oxide is 0.05% by weight or more and 1.2% by weight or less, and more preferably 0.15% by weight or more and 1.05% by weight or less. Further, the content of aluminum oxide is 0.25% by weight or more and 2.0% by weight or less, 0.25% by weight or more and 1.50% by weight or less, and further 0.5% by weight or more and 1.5% by weight % By weight or less.

The zirconia sintered body of the present invention has a total content of cobalt, aluminum, and zinc (hereinafter, also referred to as “colored metal amount”) of 5% by weight or less in terms of oxide. If the amount of the colored metal exceeds 5% by weight, the lightness L ^* becomes too low, and a sintered body having a bright color tone cannot be obtained. The amount of the colored metal is preferably 4% by weight or less, more preferably 2.85% by weight or less. Further, when the amount of the colored metal is 2.1% by weight or less, the lightness L ^* tends to be high, and the color tone of the sintered body tends to be bright. The amount of the colored metal may be 0.45% by weight or more, and more preferably 0.6% by weight or more.

The colored metal amount is a ratio of the total weight of cobalt, aluminum, and zinc converted to CoO, Al ₂ O _3, and ZnO, respectively, based on the weight of the zirconia sintered body of the present invention.

  The zirconia sintered body of the present invention contains a colored oxide, and the remainder is zirconia. The zirconia is preferably zirconia containing a stabilizer.

  Zirconia may have a stabilizer content of 2.0 mol% or more and 5.0 mol% or less, further 3.1 mol% or more and 5.0 mol% or less, or even 3.1 mol% or more and 3.8 mol% or less. . By including the stabilizer in the above range, the zirconia in the sintered body becomes a single phase of tetragonal zirconia or zirconia having a tetragonal main phase. Thereby, the mechanical strength of the zirconia sintered body of the present invention becomes higher.

  The content (mol%) of the stabilizer in the zirconia sintered body of the present invention is a molar ratio of the stabilizer to the total of zirconia and the stabilizer in the zirconia sintered body, and is determined by the following equation. Can be.

Stabilizer content (mol%)
= Stabilizer (mol) / {stabilizer (mol) + zirconia (mol)} x 100
In the above formula, the stabilizer is a mol number in terms of oxide.

The stabilizer contained in zirconia contains at least erbium oxide.
The stabilizer preferably contains, besides erbium oxide, one that does not significantly affect the color tone of the sintered body, such as yttrium oxide (Y ₂ O ₃ ), magnesium oxide (MgO), calcium oxide (CaO), and oxide. More preferably, it contains at least one member of the group consisting of cerium (CeO ₂ ), and the zirconia is particularly preferably zirconia containing erbium oxide and yttrium oxide.

When zirconia is zirconia containing erbium oxide and yttrium oxide as a stabilizer, erbium oxide and yttrium oxide-containing zirconia, the content of erbium oxide is preferably larger than the content of yttrium oxide, and yttrium oxide is preferably used. The molar ratio of erbium oxide to γ (hereinafter, also referred to as “Er ₂ O ₃ / Y ₂ O ₃ ratio”) is more than 1, more preferably 2.5 or more to 8.0 or less, and further 3.0 or more to 6.0. It is preferably 0 or less, and more preferably 3.0 or more and 4.0 or less.

Although the zirconia sintered body of the present invention exhibits a purple color tone, L ^* , a ^* and b ^{* in} the L ^* a ^* b ^* color system (hereinafter, simply referred to as "L ^* ", "a ^* " and also referred to as a ^{"b *".),} respectively, and to be ^{35 ≦ L * ≦ 60,2 ≦ a} * ≦ 20 and -60 ≦ ^{b *} ≦ -10.

More preferably, L ^* is 39.5 or more and 63.4 or less, a ^* is 3.6 or more and 14.2 or less, and b ^* is -48.5 or more and -7.8 or less. More preferably, 9 ≦ a ^* ≦ 20 and −60 ≦ b ^* ≦ −40. Thereby, the color tone of the zirconia sintered body of the present invention tends to be clearer blue-violet.

  The higher the strength of the zirconia sintered body of the present invention, the more applications to which it can be applied. Therefore, the zirconia sintered body of the present invention preferably has a three-point bending strength of 1100 MPa or more, more preferably 1200 MPa or more. The three-point bending strength may be 1200 MPa or more and 1350 MPa or less.

  Next, a method for producing a zirconia sintered body of the present invention will be described.

  The zirconia sintered body of the present invention is formed by mixing and sintering a composite oxide of cobalt and aluminum, zinc oxide, aluminum oxide, erbium oxide and zirconia so as to satisfy the above composition. Can be manufactured.

  Further, as a preferred method for producing the zirconia sintered body of the present invention, a mixing step of mixing a composite oxide of cobalt and aluminum, zinc oxide and aluminum oxide, and erbium oxide-containing zirconia, and a forming step of forming the obtained mixture And a sintering step of sintering the obtained molded body.

  In the mixing step, a composite oxide of cobalt and aluminum (Co-Al composite oxide), zinc oxide and aluminum oxide, and erbium oxide-containing zirconia are mixed. By mixing the erbium oxide-containing zirconia and the Co-Al composite oxide, erbium, cobalt, and aluminum in the obtained zirconia sintered body are more uniformly distributed. As a result, the sintered body tends to exhibit a purple coloration without color unevenness.

  The erbium oxide-containing zirconia is preferably erbium oxide solid solution zirconia. As more preferred erbium oxide solid solution zirconia, erbium oxide solid solution zirconia obtained by mixing and drying an aqueous hydrated zirconia sol and an erbium compound, and then calcining at 1000 ° C to 1200 ° C can be exemplified.

  Examples of the erbium compound include at least one of the group consisting of erbium oxide, hydrated erbium oxide, erbium oxide sol, erbium hydroxide, erbium chloride, and erbium nitrate, and further include at least one of erbium oxide and erbium chloride. it can.

  When mixing the hydrated zirconia sol aqueous solution and the erbium compound, a stabilizer other than erbium oxide or a precursor thereof may be mixed. Thereby, zirconia in which erbium oxide and the stabilizer are dissolved can be obtained.

  As a stabilizer or a precursor thereof, at least one oxide, hydrated oxide, sol, or hydroxide of a group consisting of yttrium (Y), magnesium (Mg), calcium (Ca), and cerium (Ce) , Chlorides, and nitrates.

  Since it is particularly preferable that the stabilizer other than erbium oxide is yttria, the stabilizer or its precursor is at least a member of the group consisting of yttria, hydrated yttria, yttria sol, yttrium hydroxide, yttrium chloride, and yttrium nitrate. At least one of yttria and yttrium chloride can be mentioned.

  The hydrated zirconia sol after mixing with the erbium compound and, if necessary, the stabilizer or its precursor, may be appropriately dried and calcined.

  The Co-Al composite oxide, zinc oxide, and aluminum oxide are preferably mixed with erbium oxide-containing zirconia so that the composition of the zirconia sintered body of the present invention is obtained.

  The content of the Co—Al composite oxide, zinc oxide, and aluminum oxide in the mixture is 0.01 to 1% by weight of the Co—Al composite oxide and 0.05 to 1% by weight of the zinc oxide. 0.2% by weight or less, and aluminum oxide of 0.25% by weight or more and 2.0% by weight or less.

  Further, it is preferable to mix aluminum oxide and zinc oxide such that the Zn / Al ratio in the mixture is 0.15 or more and less than 0.9. As a result, the brightness of the obtained zirconia sintered body increases, and the sintered body exhibits a clearer purple color.

  The mixing method is arbitrary as long as the composition of the obtained mixture becomes uniform, and may be either wet mixing or dry mixing. Mixing is preferably wet mixing, and more preferably wet mixing using a ball mill, so that the resulting mixture becomes more uniform.

  In the forming step, the mixture obtained in the mixing step is formed. Any method can be used as long as a molded article having a desired shape can be obtained. Examples of the molding method include at least one of a group consisting of press molding, cold isostatic molding, sheet molding, injection molding, and cast molding.

  In the sintering step, the molded body obtained in the molding step is sintered. Any sintering method can be applied. From an industrial viewpoint, the sintering step is preferably a simple sintering method, and is preferably normal pressure sintering. In addition, the normal pressure sintering is a method of sintering by simply heating a compact without applying an external force to the compact during sintering.

  The sintering atmosphere may be any of an oxidizing atmosphere, an inert atmosphere, and a reducing atmosphere, but is preferably an oxidizing atmosphere, and more preferably an air atmosphere.

  The sintering temperature may be from 1300 ° C to 1500 ° C.

  In a manufacturing method including two or more sintering processes, such as performing an HIP process after normal pressure sintering, the color tone of the sintered body tends to change, and reproducibility tends to be low. Therefore, in the manufacturing method of the present invention, it is preferable that the process of heating to 900 ° C. or more is only a sintering process, and the sintering process is performed under atmospheric pressure sintering at 1400 ° C. to 1500 ° C. in the air. It is preferable that there is no step of heating the sintered body to 900 ° C. or more after the step. The zirconia sintered body of the present invention tends to have a three-point bending strength of 1100 MPa or more even with such a sintering method.

  According to the present invention, a purple zirconia sintered body suitable for industrial production can be provided.

  Furthermore, since the zirconia sintered body of the present invention exhibits an aesthetically high purple color, and further exhibits a bluish purple color, it is used not only for known zirconia sintered bodies but also for applications requiring decorative properties such as various exterior members. Can be used.

Powder X-ray diffraction pattern of zirconia sintered body of Example 22

  Hereinafter, the present invention will be described specifically. However, the invention is not limited to these examples.

(Measurement of density)
The density of the sintered body sample was measured by the Archimedes method.
(Measurement of color tone)
The color tone of the sintered body sample was measured by measuring color parameters L ^* , a ^* , and b ^* specified in JISZ8729. To measure the color tone, the surface of the sintered body polished to a mirror surface was measured. The color tone was measured at three points, and the average value was used as the color tone of each sample.
As a pretreatment, the surface of the sintered body sample was ground by 0.3 mm and mirror-polished until no grinding marks were left.
(Strength of sintered body)
The three-point bending strength of the sintered body sample was measured by a method based on JIS R1601.

Example 1
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. YCl ₃ and ErCl ₃ were added to the hydrated zirconia sol such that the Y ₂ O ₃ concentration was 3.0 mol% and the Er ₂ O ₃ concentration was 3.1 mol%.

The zirconia sol after the addition was dried at 180 ° C. and then fired at 1150 ° C. for 2 hours to obtain a powder. The obtained powder was washed with distilled water, and then dried at 110 ° C. to obtain a zirconia powder containing 0.72 mol% of Y ₂ O ₃ and 2.41 mol% of Er ₂ O ₃ .
CoAl ₂ O ₄ was added to the obtained zirconia powder in an amount of 0.1% by weight, ZnO was added in an amount of 0.45% by weight, and Al ₂ O ₃ was added in an amount of 0.75% by weight. ₂ O ₄ powder, ZnO powder and Al ₂ O ₃ powder were mixed.
Distilled water was added to the obtained mixed powder to obtain a slurry having a solid content of 45% by weight. The slurry was pulverized and mixed by a ball mill using zirconia balls having a diameter of 10 mm. The pulverization and mixing were performed such that the particle size of the mixed powder was Dmax ≦ 5.5 μm.
After mixing, the slurry was dried and passed through an opening of 180 μm to obtain a raw material powder.

5 g of the raw material powder was put into a mold having a diameter of 25 mm, and press-molded at a molding pressure of 98 MPa to obtain a molded body. A zirconia sintered body of this example was obtained. The obtained zirconia sintered body had a density of 6.228 g / cm ³ . Table 1 shows the stabilizer content, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 2
A method similar to that of Example 1 except that the CoAl ₂ O ₄ powder was 0.30% by weight, the ZnO powder was 0.70% by weight, and the Al ₂ O ₃ powder was 0.75% by weight. Thus, a zirconia sintered body of this example was obtained. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 3
A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that the ZnO powder was set to 0.45% by weight and the Al ₂ O ₃ powder was set to 0.50% by weight. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 4
A method similar to that of Example 1 except that the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.90% by weight, and the Al ₂ O ₃ powder was 1.50% by weight. Thus, a zirconia sintered body of this example was obtained. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 5
A zirconia sintered body of this example was obtained in the same manner as in Example 1, except that the Al ₂ O ₃ powder was changed to 0.50% by weight. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 6
A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that the amount of CoAl ₂ O ₄ powder was 0.05% by weight and the amount of ZnO powder was 0.15% by weight. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 7
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.90% by weight, and the Al ₂ O ₃ powder was 1.00% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 8
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. A zirconia powder was obtained in the same manner as in Example 1, except that ErCl ₃ was added to the hydrated zirconia sol such that the Er ₂ O ₃ concentration was 4.66 mol%. The obtained zirconia powder contained _Er 2 _{O 3} of 4.66mol%.
A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that the zirconia powder was used. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 9
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. YCl ₃ and ErCl ₃ were added to the hydrated zirconia sol such that the Y ₂ O ₃ concentration was 0.36 mol% and the Er ₂ O ₃ concentration was 2.77 mol%. The resulting zirconia powder contained 0.36 mol% of Y ₂ O ₃ and 2.77 mol% of Er ₂ O ₃ .
A zirconia sintered body of this example was obtained in the same manner as in Example 1 except that the zirconia powder was used. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 10
Same as Example 1 except that CoAl ₂ O ₄ powder was 0.05% by weight, ZnO powder was 0.15% by weight, and Al ₂ O ₃ powder was 0.50% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 11
A zirconia sintered body of this example was obtained in the same manner as in Example 1, except that the CoAl ₂ O ₄ powder was 0.05% by weight and the ZnO powder was 0.25% by weight. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 12
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.65% by weight, and the Al ₂ O ₃ powder was 1.50% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 13
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.75% by weight, and the Al ₂ O ₃ powder was 1.25% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 14
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.05% by weight, the ZnO powder was 0.85% by weight, and the Al ₂ O ₃ powder was 1.25% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 15
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. A zirconia powder was obtained in the same manner as in Example 1, except that ErCl ₃ was added to the hydrated zirconia sol such that the Er ₂ O ₃ concentration was 3.16 mol%. The obtained zirconia powder contained _Er 2 _{O 3} of 3.16mol%.

The zirconia powder was used, the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.75% by weight, and the Al ₂ O ₃ powder was 1.25% by weight. Except for this, the zirconia sintered body of this example was obtained in the same manner as in Example 1. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 16
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.30% by weight, the ZnO powder was 1.00% by weight, and the Al ₂ O ₃ powder was 1.50% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 17
The zirconia sintered body of the present example was obtained in the same manner as in Example 1 except that the CoAl ₂ O ₄ powder was 0.05% by weight and the Al ₂ O ₃ powder was 1.00% by weight. Was. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 18
Same as Example 1 except that CoAl ₂ O ₄ powder was 0.05% by weight, ZnO powder was 0.85% by weight, and Al ₂ O ₃ powder was 1.00% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 19
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.30% by weight, the ZnO powder was 0.95% by weight, and the Al ₂ O ₃ powder was 1.50% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 20
Same as Example 1 except that CoAl ₂ O ₄ powder was 0.05% by weight, ZnO powder was 0.25% by weight, and Al ₂ O ₃ powder was 0.50% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 21
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.20% by weight, the ZnO powder was 0.70% by weight, and the Al ₂ O ₃ powder was 1.25% by weight. The zirconia sintered body of this example was obtained by a suitable method. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results.

Example 22
A zirconia sintered body of this example was obtained in the same manner as in Example 1, except that the erbium oxide-containing zirconia powder obtained in the same manner as in Example 15 was used. Table 1 shows the stabilizer content of the obtained zirconia sintered body, Table 2 shows the composition of the sintered body, and Table 3 shows the evaluation results. Further, the three-point bending strength of the zirconia sintered body of the present example was 1240 MPa. FIG. 1 shows an XRD pattern of the zirconia sintered body of this example. Since there is no peak of erbium oxide, it can be confirmed that erbium oxide is dissolved in zirconia.

Comparative Example 1
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. A zirconia powder was obtained in the same manner as in Example 1, except that ErCl ₃ was added to the hydrated zirconia sol such that the Er ₂ O ₃ concentration became 3.1 mol%. The obtained zirconia powder contained 3.1 mol% of Er ₂ O ₃ .
Except that the zirconia powder was used, CoAl ₂ O ₄ powder was 0.10% by weight, ZnO powder was not mixed, and Al ₂ O ₃ powder was 0.15% by weight. A zirconia sintered body of this comparative example was obtained in the same manner as in Example 1. Table 4 shows the stabilizer content of the obtained zirconia sintered body, Table 5 shows the composition of the sintered body, and Table 6 shows the evaluation results.
The zirconia sintered body of this comparative example did not contain zinc, and its color tone was red-black.

Comparative Example 2
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. YCl ₃ and ErCl ₃ were added to the hydrated zirconia sol such that the Y ₂ O ₃ concentration was 0.23 mol% and the Er ₂ O ₃ concentration was 3.00 mol%. The obtained zirconia powder contained _Y 2 _{O 3} and 3.00 mol% of _Er 2 _{O 3} of 0.23 mol%.
The zirconia powder was used, the CoAl ₂ O ₄ powder was 1.50% by weight, the ZnO powder was 3.00% by weight, and the Al ₂ O ₃ powder was 3.00% by weight. Except for this, a zirconia sintered body of this comparative example was obtained in the same manner as in Example 1. Table 4 shows the stabilizer content of the obtained zirconia sintered body, Table 5 shows the composition of the sintered body, and Table 6 shows the evaluation results.
Since the zirconia sintered body of this comparative example contained a large amount of a colored metal, the color tone was dark blue.

Comparative Example 3
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.05% by weight, the ZnO powder was 0.55% by weight, and the Al ₂ O ₃ powder was 0.50% by weight. The zirconia sintered body of this comparative example was obtained by a suitable method. Table 4 shows the stabilizer content of the obtained zirconia sintered body, Table 5 shows the composition of the sintered body, and Table 6 shows the evaluation results.
Since the zirconia sintered body of this comparative example contained a large amount of a colored metal, the color tone was slightly bluish red.

Comparative Example 4
The aqueous solution of zirconium oxychloride was hydrolyzed to obtain a hydrated zirconia sol. YCl ₃ and ErCl ₃ were added to the hydrated zirconia sol such that the Y ₂ O ₃ concentration was 0.41 mol% and the Er ₂ O ₃ concentration was 3.15 mol%. The resulting zirconia powder contained 0.41 mol% of Y ₂ O ₃ and 3.15 mol%) of Er ₂ O ₃ .
The zirconia powder was used, the CoAl ₂ O ₄ powder was 2.50% by weight, the ZnO powder was 4.0% by weight, and the Al ₂ O ₃ powder was 6.0% by weight. Except for this, a zirconia sintered body of this comparative example was obtained in the same manner as in Example 1. Table 4 shows the stabilizer content of the obtained zirconia sintered body, Table 5 shows the composition of the sintered body, and Table 6 shows the evaluation results.
Since the zirconia sintered body of this comparative example contained a large amount of a colored metal, the color tone was bright blue.

Comparative Example 5
Same as Example 1 except that the CoAl ₂ O ₄ powder was 0.10% by weight, the ZnO powder was 0.60% by weight, and the Al ₂ O ₃ powder was 0.25% by weight. In a simple manner. However, the zirconia sintered body was broken by sintering, and the color tone could not be evaluated. Table 4 shows the stabilizer content of the obtained zirconia sintered body, and Table 5 shows the composition of the sintered body.

  The zirconia sintered body of the present invention is a high-density, high-purity treasure that is dense and purple, exhibits a stable hue even when deteriorated by use, and has excellent aesthetics. It can be used for various members such as ornaments and decorative members, for example, clock parts, exterior parts of portable electronic devices, and the like.

Claims (6)

  It contains a composite oxide of cobalt and aluminum, erbium oxide, zinc oxide, aluminum oxide and zirconia, and has a total content of cobalt, aluminum and zinc of 5% by weight or less in terms of oxide, A zirconia sintered body having a weight ratio of less than 0.9 in terms of oxide.   The zirconia sintered body according to claim 1, wherein a total content of a composite oxide of cobalt and aluminum, zinc oxide, aluminum oxide, and erbium oxide is 20% by weight or less.   3. The zirconia sintered body according to claim 1, wherein a content of the zirconia stabilizer is 2.0 mol% or more and 5.0 mol% or less. 4. L ^* a ^* b ^{* L} in color system *, claim ^{a *} and ^{b *, respectively, 35 ≦ L * ≦ 60,2 ≦} a * ≦ 20, and a -60 ≦ ^{b *} ≦ -10 The zirconia sintered body according to any one of claims 1 to 3.   A mixing step of mixing a composite oxide of cobalt and aluminum, zinc oxide and aluminum oxide, and erbium oxide-containing zirconia, a forming step of forming the obtained mixture, and a sintering step of sintering the obtained formed body The method for producing a zirconia sintered body according to any one of claims 1 to 4, comprising:   The method according to claim 5, wherein the sintering step is normal pressure sintering.

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