JPS6291467A - Light transparent zirconia sintered body - 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 "Industrial Application Field" The present invention relates to a zirconia sintered body with excellent translucency.

[Prior art] Conventionally, as a translucent zirconia sintered body, Zr02-Y
The two-component sintered bodies of 2O, series and ZrO2-Can series were published in Journal of Q The American Fist Ceramic'.
Journal or1'l+(
3American Ceramic 5ociety
) Volume 50, page 532 (1967) and Journal φ of Less-Common Metals (Journal
ol' l, oss-Common Metals)
As reported in Volume 13, page 530 (1967),
The light transmittance of these sintered bodies is about 1096, and it is difficult to say that they are truly translucent materials.

[Problems to be Solved by the Invention] The present invention provides a zirconia sintered body having extremely high translucency and which can be used as an optical material.

[Means to solve the problem] Generally, in order to impart translucency to ceramics, the density of the sintered body is set to 1. It is said that it is effective to reduce the scattering of light due to pores and to increase the diameter of the sintered body to reduce the scattering of light due to grain boundaries. As a result of conducting research on ZrO2-Y2O3-based sintered bodies, the present inventor found that l'r growth of the sintered bodies was significantly promoted by adding TiO2 to the ZrO2-Y2O system. Ta.

However, in general, significant porosity growth results in pores remaining within the sintered body because the growth rate of pore particles becomes faster, resulting in a disadvantage that a dense sintered body is difficult to obtain. . In order to overcome this drawback, the present inventor conducted an inspection of the characteristics of the raw material powder and the sintering conditions, and
3-Y20. It has been discovered that remarkable grain growth and complete densification can be achieved without any conflicting results in a system in which TlO2 is added, and a zirconia sintered body having high translucency has been obtained.

The sintered body of the present invention is ZrO2-'/203-TlO2
of the system, v, 0. 2 moles of 96 or more and'
l' i 0. must contain 3 to 20 moles96.

This TiO23 to 20 mole (the sintered body is Y2O12
Around mole 96, it is the Ichitsuno' product tlt phase, and Y2O3f
When i mole (,) 6 or more is 1-, it becomes a cubic H1 (phase, between which a mixed crystal with IEjj product and) γ horn crystal is formed. Iγ no j
Since the sintered body used by Shinanakagawa is optically homogeneous, there is no scattering due to one field, and it exhibits the highest translucency. However, it is not necessary for Y2O to have more than 9 mol% of a. The grain size of the sintered body increases as the Tie2 added magnetism increases. For example, when sintering is carried out at 1700°C for 2 hours, 50 to 10
0 μm]), 1O mol') 6 T I 02, 100
The particle size is ~200μIn. Light transmittance tends to increase as the particle size increases. Tatashi, TlO2
When the content of m exceeds 20 mol%, another compound ZrTiO4 is formed between No. 2111 and L7, so that the light transmittance is significantly reduced. Therefore, in order to make the translucency sufficiently high, the content of 'r lo is 3 to 20 mol96
, preferably 5 to 20 mol %.

The present inventor has discovered that Y2O3B mol% or more 1-1T i 02 is 3 to 20 mol%, and a zirconia sintered body having a fine 12i^ of similar oxides on a lanthanum base cloth has translucency as well as
It was discovered that it also has fluorescent properties.

Its lanthanum-based rare earth oxide content is 0.1 to 3
The preferred amount is 1 mol %, and it is preferably around 1 mol % to best exhibit fluorescence.

In addition, examples of lanthanum-based rare earth oxides include Nd201,
Examples include Eu2o9 and Tb2O3.

The method for manufacturing the sintered body of the present invention will be explained in detail below.

The starting material is preferably a high purity fine powder. For example, ZrO2-Y2O3 fine powder with an average particle size of 0.1 μm or less synthesized by a wet method and an average particle size of 0.5 μm.
Powder that is sufficiently well mixed with TlO2 fine powder of 0.0 m or less may be used, but a sufficiently well mixed powder of ZrO2'/203 series powder and TlO2 powder is fired, and the average particle size [1,
It is even more preferable to obtain a solid solution of each component obtained by pulverizing the powder to a size of 3 μm or less. Alternatively, ZrO2 with an average particle diameter of 0.3 μm or less synthesized by coprecipitation method
-Y203- TlO2-based fine powder or ZrO2-Y203
Mix the titanium alkoxide solution with the system powder, dry it,
Those obtained by firing and pulverizing and having an average particle size of 0.3 μm or less are also suitable raw materials. The addition of lanthanum-based rare earth oxides can be applied to Zr02-Y203- before calcination of oxalates, etc.
This may be carried out by mixing the TlO2-based powder precursor and then firing it. Such powder is molded into a predetermined shape by a molding method such as a rubber press or slip casting method, and then fired. The firing temperature should be 1400°C or higher, and in order to achieve sufficient grain growth, the firing temperature should be 1600-1
800°C is preferred. In addition, the temperature increase rate is l1l(1
℃711r or less is preferred, u).

The firing atmosphere may be air, or in order to obtain even higher translucency, it is preferable to use oxygen. The fired body obtained in this way already has high translucency [7], but in order to make it even more translucent, it may be necessary to process it in a hot isostatic press. . As processing conditions, pressure medium: argon, pressure: 500M
Pa-1-,? , tJ degree is preferably selected from 1400 to 1700°C. This treatment brings the sintered body into a reduced state, so it becomes black. Therefore, it is necessary to oxidize this black sintered body in air or oxygen to return it to its original color. The treatment temperature is 800°C or higher, preferably 1000°C or higher, and 1200°C is sufficient.

The sintered body thus obtained has a density of 99% or more of the theoretical value and exhibits high transparency to light from the visible light range to the infrared light range of wavelengths 350 to 7DDOnI11. In addition, those containing lanthanum-based clay oxides, for example those containing EIJ203, turn red when exposed to ultraviolet irradiation.
Those containing 2Q3 emit green fluorescent light.

[Effects of the Invention] The sintered body of the present invention has excellent translucency and a high refractive index, and has the advantage that large products and products with complicated shapes can be easily manufactured. Furthermore, it can be used as a transparent material having fluorescence emission by containing a lanthanum-based clay oxide. Hence the window in the furnace body.

Light-transmitting materials that require heat resistance and heat insulation, such as cladding tubes for heating elements and protective tubes for lamps; Infrared-transmitting materials, such as infrared lenses and windows for infrared light-receiving elements; fluorescent display materials, solid-state oscillation 4
It can be used for industrial applications such as porcelain dyes, ultraviolet ray nail meters, etc.; decorative amulets for jewelry, etc.

[Example] The present invention will be explained using examples.

Powder Production Examples 1 to 3 A mixed aqueous solution of zirconium oxychloride and yttrium chloride is hydrolyzed by boiling, and the resulting sol is dried, calcined at 900°C, and pulverized to produce Y2
A fine zirconia powder containing O was obtained. This powder and titanium isopropoxide solution were placed in ethanol, wet mixed, dried under reduced pressure, calcined at 950°C, and pulverized to obtain a ZrO2-Y203-TiO2-based fine powder.

Powder Production Examples 4 to 6 Zirconia fine powder containing Y2O, which was obtained in the same manner as Powder Production Examples 1 to 3, and titania fine powder were wet mixed in ethanol, dried, fired at 900°C, and pulverized. A ZrO2-Y203-Tto2 fine powder was obtained.

Powder Production Example 7 A titanium isopropoxide solution was added to a mixed aqueous solution of zirconium oxychloride and yttrium chloride, and the mixture was hydrolyzed by continuing heating for 3 days. After drying the resulting sol, it was calcined at 920°C. By pulverizing, Zr02-'/,03-TiO2-based fine powder was obtained.

Powder production examples 3 to 13 Zirconia powder was obtained in the same manner as in Powder Production Examples 1 to 3.

Additionally, water was added to the titanium isopropoxide solution to obtain a hydrolysis product of hydrated titania. -1- Wet mixing the zirconia powder and the hydrolysis product of hydrated titania,
After drying, it is baked at 1000℃ for 2 hours, crushed and Z
A rO2'/203-Ti02-based fine powder was obtained.

Powder Production Examples 14 to 18 Neodymium oxalate was added to a mixture of zirconia powder and a hydrolysis product of hydrated titania obtained in the same manner as in Powder Production Examples 3 to 13, wet-pulverized, and dried.
It was baked at 000°C for 1 hour. The obtained calcined powder was pulverized to form Zr02-Y203-T in which Nd and 03 were dissolved in solid solution.
A lO2-based fine powder was obtained.

The composition and primary particle size of the fine powder described below are as shown in Table 1.

Sintering Example A The powders obtained in Powder Production Examples 1 to 7 were molded into a disk shape using a mold and a rubber press. These molded bodies were placed in a tube furnace, and the temperature was maintained at -L 1700°C for 2 hours at a rate of 40°C/h and r, and then the temperature was lowered. The sintered body thus obtained was placed in a pot isostatic press and heated to 1,000 atmospheres using argon as a pressure medium.

150 [Processed at 1°C for 30 minutes. The sintered body after treatment is
All of them were black, so I put them in the tube furnace again.
The temperature was maintained at 1200° C. for 4 hours without oxygen flow. After cooling, all of the sintered bodies taken out had very high translucency. The crystal phase was identified by X-ray diffraction [7], and it was found that the sintered body obtained from Powder Production Example 4 was a W-shaped single phase, or the rest was entirely cubic It +1+.

Test Example A Some of the sintered bodies obtained in Sintering Example A were selected and their light transmittance was measured. Al11 constant sample (7mm thickness 05
A mirror-polished piece on both sides with a thickness in the range of 1.5 mm was used. The results are shown in Figure 1. Reference numerals 1, 2, and 3 in the figure indicate that the raw material powders were obtained from powder production examples 2, 5, and 3, respectively.

From FIG. 1, it can be seen that the sintered body of the present invention has a transmittance of 409 oJ 1- at a thickness ln+m in the range from 1 to 1.

Test Example A′ 'l'' i 0. For the purpose of examining the effect of T r 02
Using the same method as in sintering example A, using 3kt" powder (manufacturing example 2) and 'I" powder not containing 102 (zirconia containing 8 mol%v, 0.0%), a disk-shaped material with a thickness of Innn was sintered. L”i
I got a body.

The TiO2 white sample exhibits very high translucency at 47 t=
However, the sample that does not contain T i 02 has a white color.
There were 2. When the transmittance in the visible light range was measured using the J' method of Test Example 1, the transmittance was about 4096 for the former, but about 7% for the latter. The structures of the sintered bodies of these two samples were also observed using a scanning electron microscope.

Figure 2 is a microscopic photograph of the same, A shows one containing TlG, and B shows one without it.

As is clear from Fig. 2, by adding TlO3, the t+>'-J' diameter becomes 200 μm in diameter, and remarkable grain growth is achieved, and the porosity is extremely reduced. . This result proves that the addition of TiO7 plays an important role in increasing translucency.
-I am.

Sintering Example B The powders obtained in Powder Production Examples 3 to 13 were molded into a plate shape using a mold and a rubber press. These molded bodies were placed in a tube furnace, and the temperature was maintained at 5[-1500 to 175+]C at a rate of 1C/hr for 2 hours while oxygen was being passed through, and then the temperature was lowered. All of the obtained sintered bodies had high translucency. Next, the cut pieces obtained by cutting these sintered bodies in half are subjected to a hot isostatic press (H
I P) put it in the device and use argon as pressure medium 1000
It was treated at atmospheric pressure + 1500-1700°C for 30 minutes. Since all of the sintered bodies after treatment had a black color, they were placed in the tube furnace again and held at 1200° C. for 2 hours while flowing oxygen. After cooling, all of the sintered bodies taken out had very high translucency. The crystal phases of the obtained sintered bodies were all cubic. The particle size and density are shown in Table 2.

Test Example B The visible light and infrared light transmittance of the sintered body obtained in Sintering Example B was measured. A sample with a thickness of 0.8 mm and mirror polished on both sides was used as the measurement sample.

All of the samples exhibited transparency to light with wavelengths ranging from visible light to infrared light ranging from 0.35 to 7 μm. As a representative value,
Table 2 shows the straight line transmission (14) ratio for light of 0.0 μm.

Sintering Example C A sintered body was obtained in the same manner as Sintering Example B using the zirconia powders obtained in Powder Production Examples 14 to 18. The crystal phases of the obtained sintered bodies were all cubic. The particle size and density are shown in Table 3.

Test Example C = 14- The light transmittance of visible light and red flash light of the sintered body obtained in Sintering Example C was measured. A sample with a thickness of 0.8 mm and mirror-polished surfaces on both sides was used as a measurement sample.

All samples exhibited transparency to light with wavelengths ranging from visible light to infrared light from 0.35 to 7 μm. Sintered body trial shrine No.
The visible light transmittance of l4 is shown in FIG. Also, 0.2
When irradiated with 6 μm ultraviolet rays, sintered body sample No.
and 16 emitted red and 15 green fluorescence.

[Brief explanation of drawings]

FIG. 1 is a graph showing the light transmittance in Test Example A. FIG. 2 is a micrograph showing the ladle structure of the sintered body in Test Example A'. FIG. 3 is a graph showing the visible light transmittance of sintered body sample No. 14 in Test Example C. In the diagram? ] The meaning of the number is as follows. 1: Raw material powder Powder production example 2 2: Raw material powder Powder production example 5 3: Raw material powder Powder production example 3 A: Sintered body containing TlO2 B: Sintered body not containing TlO2 Patent applicant Toyo Soda Kogyo Co., Ltd. 3 Figure 2

Claims (4)

[Claims] (1) A translucent zirconia sintered body made of zirconia containing 2 mol% or more of Y_2O_3 and 3 to 20 mol% of TiO_2. (2) The translucent zirconia sintered body according to claim (1), which is made of zirconia containing 6 mol% or more of Y_2O_3. (3) The translucent zirconia sintered body according to claim (1), which is made of zirconia containing 6 to 9 mol% of Y_2O_3 and 5 to 20 mol% of TiO_2. (4) 6 mol% or more of Y_2O_3 and 3 to 3% of TiO_2
20 mol% and lanthanum rare earth oxide 0.1-3
Translucent and fluorescent zirconia sintered body made of zirconia containing mol%.