JP2821680B2 - Colored zirconia ceramics - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a colored zirconia ceramic in which CoO is contained in a zirconia base.

(Prior art)

In recent years, colored zirconia ceramics have been developed and used for decorative members such as watch cases, dials, and cufflinks.

Such colored zirconia ceramics are disclosed in
As shown in JP-A-105055, it is obtained by adding a pigment composed of a metal oxide and a stabilizer to zirconia.For example, if CoO was used as a pigment, a blue colored zirconia ceramic could be obtained. .

[Problems of the prior art]

When such colored zirconia ceramics is used as a decorative member, it is necessary to finely control the tone of the color tone in accordance with the combination with other members. However, in the conventional colored zirconia ceramics as described above, in order to control the shading of the color tone, Co is a pigment.
There was no choice but to change the O content, and it was very difficult to control the delicate color tone.

[Means for solving the problem]

The present invention in view of the above, the zirconia and Y ₂ O _3, MgO, relative to 100 wt% of the main component consisting of a stabilizing agent such as CaO, Al ₂ CoO, as a pigment for 0.1 to 5 wt% and tone control O ₃ was contained 0.1 to 20% by weight is obtained by forming a colored zirconia ceramic.

The colored zirconia ceramics of the present invention develops a blue color due to CoO present between the zirconia particles, but the added Al ₂ O ₃ and a part of the CoO react to form light blue CoO-Al ₂ O ₃ , This makes the blue lighter. Increasing the amount of Al ₂ O ₃ makes the blue color lighter, while decreasing the amount of Al ₂ O ₃ makes the blue color darker. Therefore, by controlling the addition amounts of CoO and Al ₂ O ₃ , it is possible to finely adjust the shading.

The method for producing the colored zirconia ceramics of the present invention is as follows. First, zirconia raw material powder having an average particle size of 0.15 μm or less, preferably 0.06 μm or less, and a stabilizer such as Y ₂ O ₃ , MgO, CaO having an average particle size of 2 μm or less, preferably 1 μm or less. Used. Or,
A coprecipitated zirconia powder to which a predetermined amount of a stabilizer has been added may be used. When this powder is used, the stabilizer and zirconia are mixed more densely and uniformly, so that the crystal grains of the sintered body are This has the advantage that the diameter is made uniform.

Furthermore, the required amount of Co in the zirconia powder and stabilizer is
O, Al ₂ O _{3 and} after adding a known sintering accelerator, if necessary, after press-molding the mixed powder, 1200 ~ 1700 ° C preferably 13
By firing at a temperature of 50 to 1550 ° C. in a vacuum furnace or an oxidation furnace, desired colored zirconia ceramics can be obtained.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

Example 1 3 mol% of Y ₂ as a stabilizer in high purity zirconia powder
O ₃ to 100 wt% of the main component was added to, CoO of various content as shown in Table 1, the Al ₂ O ₃ was added, and pulverized for 3 days with a vibration mill by adding further 100 wt% of water And dried. This was passed through 120 mesh, paraffin wax was added, and further passed through 80 mesh. This mixture is pressed at a molding pressure of 1t.
It was molded into a 7 × 7 × 65 mm rod at on / cm ² and fired at 1450 ° C. in an oxidizing atmosphere.

Table 1 shows the results of examining the transverse rupture strength, toughness, and color tone of the thus obtained colored zirconia ceramics.

The bending strength is measured according to the three-point bending test method of JIS-R-1601, and the toughness is determined by the critical stress intensity factor (K _IC ) when ceramics break due to the growth of microcracks.
Was measured by SENB (Single Edge Notched Beam) method. The color tone is represented by DIC No.

As shown in Table 1, increasing the content of CoO makes the color tone deeper,
It can also be seen that the color tone becomes paler when the content of Al ₂ O ₃ is increased even if the addition amount of CoO is the same, and fine control of the color tone becomes possible. Further, with respect to the content of CoO, if it was less than 0.1% by weight as in No. 1, no coloring was obtained, and if it exceeded 5% by weight as in No. 18, the bending strength and toughness were extremely poor.

Example 2 Next, with respect to the colored zirconia ceramics obtained in the same manner as in Example 1 except that 9 mol% of MgO was used in place of Y ₂ O ₃ as a stabilizer, transverse strength, toughness and color tone were examined. The results were as shown in Table 2.

Also in this case, as in Example 1, when the content of Al ₂ O ₃ is increased, the color tone becomes lighter, and it can be seen that subtle color tone control becomes possible.

[Effects of the Invention] As described above, according to the present invention, 0.1% of CoO as a pigment is added to 100% by weight of a main component comprising zirconia and a stabilizer.
5 wt%, and by which the Al ₂ O ₃ is contained 0.1 to 20 wt%, acts as Al ₂ O ₃ causes the lightly coloring of CoO, the range the content of these CoO, Al ₂ O ₃ If it is changed within the above range, a delicate control of color tone can be easily performed, and a colored zirconia ceramic excellent in both transverse strength and toughness can be provided.

Claims (1)

(57) [Claims] 1. A main component 100 comprising zirconia and a stabilizer
0.1 to 5% by weight of CoO and 0.1 to 20% by weight based on the weight%
Of Al ₂ O ₃ was added, blue colored zirconia ceramic which is characterized by containing a dye source comprising CoO-Al ₂ O ₃ compound.