JPS6259571A - Colored zirconia sintered body and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a colored, high-density, high-toughness norconia sintered body used for watch cases, dials, etc.

[Conventional technology]

Conventionally, as described in JP-A-59-105055, as a zirconia-based sintered body that has a colorful color tone, stabilized zirconia with 61']14 of Cr203, Coo, Nip, MnO2, etc. has been used. It is known that colored pigments made of oxides of

In addition, zirconia crystals colored by the melting method without using such pigments are also published in "Current Status of Cubic Luconia - 1 Published by Rabidari Journal" (CUBjCZIRCO).
NIA: AN IJPDATE, TIIE LAP
IDAI? Y JOU-RNAL, INC,) ν
OL, 35. NO, 6, PP, 1194-1200.
1210-1214. It is also described in SEP, 1981.

[Problem that the invention seeks to solve]

However, in the above method of adding colored pigments to zirconia, the pigments are added in a relatively large amount of o, t-io weight, and the thermal expansion coefficient and elastic constant of the added colored pigments are Z'02 Because of the W, residual stress and thermal stress occur at the contact interface between the pigment and the ZrO2 particles, resulting in defects and cracks inside the crystalline body.
- This causes problems such as the lack of toughness, corrosion resistance, and high-temperature strength of the zirconia-based sintered body that we have produced.

On the other hand, the colorful cubic zirconia flower crystals produced by the above-mentioned melting method also produce a few tenths of a percent I/Her (several thousand pp).
H) is added to cubic ZrO2,
It is brittle in the 1st to 3rd grades, exhibits hardness G-anisotropy, and is produced by a melting method, so it also has the disadvantage of containing air bubbles.

The purpose of the present invention is to eliminate the drawbacks of conventional colored zirconia, to reduce the fineness and gloss of the mirror-like state, to improve hardness,
The present invention provides a zirconia sintered body having high strength, high toughness, I'iJ' corrosion resistance, and a colorful color tone.

[Means for solving problems]

The colored zirconia sintered body according to the present invention is made of ZrO2 containing an extremely small amount of colorant and stabilizer, and has a transparent color tone close to natural color.

Colorants include Ce, Cr, Co, Cur E
r, Ho, Fe.

Mn, Nd, Ni, Pr, Tm, Ti,
When the water-soluble compounds of V are used alone or in any combination, the amount of oxide in the sintered body is o, ooi ~ 0.0 with respect to the Z r O2 aqueous solution containing a stabilizer.
Mix to make 80 parts and 1 part. Examples of aqueous soluble compounds include chlorides, nitrates, and sulfates.

In the present invention, the colorant-containing layer is formed by Z'' containing a stabilizer.
The reason for limiting o,oot to 0.080 double star weight for 02 is that if the coloring agent is less than 0.001% by weight, the coloring effect cannot be obtained, and if the colorant exceeds 0.080 gravity 1- This is because the strength and corrosion resistance of the sintered body are poor.

In the present invention, the added colorant produces a fluorescent spectrum specific to the metal elements that make up the colorant, so if the amount added is too small, the coloring will not occur and a colorful color tone will not be obtained. I can't do it.

The limit W is o,ooi m≠%. On the other hand, the colorant L:I:ZrO2, which gives various color tones, is often present at the grain boundaries or inside the grains without forming a solid solution. , ZrO
2. The translucency of the sintered body decreases. Also Zr02
7 Trinox and colorant have different elastic modulus and thermal expansion coefficient)
It becomes y. Therefore, when the amount of colorant added increases, distortion and stress are accumulated inside the sintered body, resulting in a decrease in strength and corrosion resistance.

The color tone and strength of the sintered body are affected by the porosity of the sintered body, so in order to obtain a sintered body with high strength, uniformity, and no uneven color, the porosity should be 1. It is preferably 0% or less, preferably 0.5% or less.

Here, porosity (P) is defined below.

Theoretical Density The zirconia sintered body of the present invention typically contains ZrO2 as a main component, and further contains Y203, Cab, and NGO.

It is a sintered body containing at least one kind of stabilizer such as CeO2.

1.0-6.0 mol% for Y2O3, 6-12 mol% for MgO and CaO, 6-1 for CeO2
A partially stabilized zirconia composition containing 0 mol % has high strength.

Furthermore, the zirconia sintered body of the present invention is particularly effective for zirconia having a tetragonal crystal structure. When tetragonal zirconia is contained, mechanical properties, especially strength and toughness, are improved by the so-called stress-induced transformation mechanism, as a result of the transformation from a tetragonal to a monoclinic crystal structure in response to external stress. desirable.

When the zirconia sintered body includes the above-mentioned tetragonal crystal structure, it is preferable that the proportion of the tetragonal structure is 70 mol % or more because strength, toughness, etc. are further improved.

Such a sintered body has a monoclinic and/or cubic crystal structure in addition to a tetragonal crystal structure.

Since pinoclinic zirconia causes a decrease in strength and toughness, the monoclinic star content is preferably 5 mol % or less.

In the above, the amounts of cubic and monoclinic zirconia are determined as follows.

In other words, the star of tetragonal zirconia is obtained by X-ray diffraction of the surface of a ground sintered body, with 400 faces of cubic zirconia,
Square zirconia 004 face and square zirconia 220
Calculate from the diffraction intensity (area intensity) of the surface using the following formula.

However, for the diffraction intensity, the value after correction by the Lorentz factor is used.

CT= (B+C)X100 / (A+B+C)IB
L, CT di-tetragonal zirconia growth (mol%) A: Diffraction line intensity of 400 planes of cubic zirconia B: Diffraction line intensity of 004 planes of tetragonal zirconia C: Diffraction line intensity of 220 planes of tetragonal zirconia On the other hand, monoclinic The star of crystalline zirconia is also determined by the following formula in the same way as the case of square zirconia.

CM= (E↓F)X100 / <D+E+F) However, cM:! Li Oblinic Zirconia Star (mol %) A: Diffraction line intensity of 111 planes of tetragonal zirconia B; Diffraction line intensity of 111 planes of monoclinic zirconia C: Diffraction line intensity of 11 planes of monoclinic zirconia Coloring of the present invention Zirconia is manufactured in the following manner.

The powder is made of zirconium chloride aqueous solution (ZrOC1z aqueous solution) and yttrium chloride aqueous solution (ZrOC1z aqueous solution) with a purity of 99.9 or higher.
Prepare 78 solutions of water containing a water-soluble compound (YCIa aqueous solution) and a colorant, and apply coprecipitation method 1 hydrolysis method, sol-gel method, thermal decomposition method,
The primary particle size obtained by the gas phase method, metal alkoxide method, etc. is 0.1 μm or less, and the specific surface area is 7 to 20 n(/g
, powder having a Stokes diameter in the range of 0.2 to 2.0 μm can be suitably used.

When mixing the above-mentioned zirconium chloride aqueous solution and yttrium chloride aqueous solution in a desired ratio, for example, a coloring agent is added as an FeCl2 or pecla aqueous solution in the case of Fe, a NiCl2 aqueous solution in the case of Ni, and a CuCl2 aqueous solution in the case of Cu. Added.

) 8 For ZrO2 that has been liquefied and contains a prescribed stabilizer, the appearance of the oxide in the oxide powder after adding the colorant is o, ooi
After uniformly kneading to a weight of ~0.080 double star, heating and pulverizing to make oxide powder, rubber press method, injection molding method, mold molding method, extrusion molding method, doctor blade method, and casting. A desired molded body is created using an appropriate molding method such as a molding method.

This molded body is pre-sintered so that the relative density becomes 95% or more. Pre-sintering involves sintering the compact at a speed of 50 to 9 b/h.
Raise the temperature to 0 (1°C), 9 (1 (from 1'C to 30-50°C)
This is carried out by heating from 1300° C. to 1450° C. at a rate of 1450° C./hour and holding at that temperature for several hours.

Next, this pre-sintered body was heated at 300°C in an Ar gas atmosphere.
to 1,300°C to 1,450°C at a rate of 500°C/hour, and at the same time adjust the pressure to 1,000 to 2,000 atm at the sintering temperature, preferably 1,500 atm or higher, while applying gas pressure from room temperature. 120
It is maintained at 0 to +600'C for 1 to 2 hours and subjected to 2A hydrostatic pressurization (IIIP) treatment.

Further, during sintering, it is not necessary to apply pressure heating, and a normal pressure sintering method at 1300 to 1600°C can also be applied.

As a result, a zirconia sintered body having an average particle size of 0.3 to 2 μm, preferably 0.3 to lum, a relative density of 99% or more, and a Charpy impact value of O, 1 kgfm/c+4 or more is obtained. It will be done.

〔Example〕

A mixed solution of zirconium chloride aqueous solution @ (ZrOC12 water?8 liquid) and yttrium chloride aqueous solution (YCI3 aqueous solution) with a purity of 99.95χ having the composition shown in Table 1, and a colorant was mixed at a temperature of 80 to 150°C for 100°C. from 1
It was heated for 50 hours and hydrolyzed to create a gel-like powder. This was calcined at 800 to 1000°C, then wet-pulverized in an attritor mill and dried to obtain a raw material powder.

This raw material powder was mixed with polyvinyl alcohol as a binder, and then pressed into a predetermined shape with a mold at a pressure of 000 kg/cd to produce a molded body.

Table 1 The above molded body was heated to 900°C at a rate of 70°C/hour,
It was heated from 900°C to 1450°C at a rate of 50°C/hour and held at that temperature for 3 hours to perform T-Lun sintering.

The density of the sintered body was 95% or more of the theoretical density.

Next, this pre-sintered body is heated to 400°C in an Ar gas atmosphere, and at the same time the pressure is increased from room temperature to 1500 atm at the sintering temperature while applying gas pressure, and at this temperature for 1 to 2 hours. Hold and apply hot isostatic pressure (1!IP>
Processed.

The thus obtained zirconia sintered body was cut into a shape of 3 mw x 4 cranes x 36 cranes using a diamond cutter, and the surface was ground using a surface grinder and further polished with #400 diamond paste to create a sample for color tone III. did.

Table 2 shows the physical property values of each sample and the obtained color tone in comparison with conventional products. Here, the relative density is the specific gravity according to JIS
It was measured by the method described in Z8807-1966, and calculated as a ratio to the theoretical density. Hardness is JIS Z2245-196
Measured by the measuring method described in 1-, and the bending strength is JIS R
7111+ was determined by the measuring method described in 1601-1981. Further, the impact value was calculated by performing an impact test using a Charpy impact tester according to the test method described in JIS 87722.

As is clear from the table, the products of the present invention have rich color tones and are extremely excellent in mechanical properties such as density, strength, and toughness.

〔Effect of the invention〕

The colorful colored zirconia sintered body of the present invention is
It is highly dense, has a mirror-like finish, has a good gloss, and has high toughness, high strength, and excellent wear and corrosion resistance, so it can be used for many purposes.

For example, it is suitable as a material for colored decorative materials (tie bins, brooches, cufflinks, etc.), watch parts (watch cases, dials, etc.), mechanical tools (screwdrivers, bits), fishing gear parts, optical parts, etc.

Claims (1)

[Claims] 1, Ce, Cr, Co, Cu, Er, Ho, Fe, Mn
, Nd, Ni, Pr, Tm, Ti, and V.
A colored zirconia sintered body characterized by containing 0.001 to 0.080% by weight based on _2. 2, Ce, Cr, Co, Cu, Er, Ho, Fe, Mn
, Nd, Ni, Pr, Tm, Ti, and at least one colorant selected from the group consisting of water-soluble compounds of V,
For an aqueous solution of ZrO_2 containing a stabilizer, the amount as an oxide in the subsequent oxide powder is 0.001 to 0.
080% by weight, heat the mixture,
After crushing into oxide powder, shaping the powder and pre-sintering in a non-reducing atmosphere,
A method for producing a colored zirconia sintered body, which comprises sintering while maintaining the temperature at ~1600°C.