EP0435677A2
Expired / Lapsed
EP
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Alumina-zirconia composite sintered product and method for making the same
Assignee: Tosoh Corp
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Filing: 1990-12-27
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Granted: —
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Expires: 2010-12-27
Abstract
Abstract An alumina-zirconia composite sintered product which comprises a zirconia crystalline phase composed mainly of a tetragonal zirconia and an alumina crystalline phase is described. The sintered product has such a fine structure that regions of said alumina crystalline phase being separated with the zirconia crystalline phase at a size of from 0.1 to 2 µm on average. Preferably, the zirconia crystalline phase contains not larger than 4 mol% of yttrium oxide or not larger than 14 mol% of cerium oxide as a stabilizer. A method for making a starting composite powder and a method for making a composite sintered product using the composite powder are also described.
Inventors
- 👤 Yoshitaka Kubota
- 👤 Shigemi Yamamoto
- 👤 Hiroshi Yamamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:30
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
55 words
An alumina-zirconia composite sintered product which comprises a zirconia crystalline phase composed mainly of a tetragonal zirconia and an alumina crystalline phase, said sintered product having such a fine structure that regions of said alumina crystalline phase being separated with the zirconia crystalline phase at a size of from 0.1 to 2 µm on average.
Claim 2
Dependent Claim
55 words
An alumina-zirconia composite sintered product which comprises a zirconia crystalline phase composed mainly of a tetragonal zirconia and an alumina crystalline phase, said sintered product having such a fine structure that regions of said alumina crystalline phase being separated with the zirconia crystalline phase at a size of from 0.1 to 2 µm on average.
Claim 3
Dependent Claim
77 words
An alumina-zirconia composite sintered product which comprises a zirconia crystalline phase composed mainly of a zirconia crystalline phase containing not larger than 4 mol% of yttrium oxide or not larger than 14 mol% of cerium oxide as a stabilizer and an alumina crystalline phase, said sintered product having such a fine structure that regions of said alumina crystalline phase being separated with the zirconia crystalline phase at a size of from 0.1 to 2 µm on average.
Claim 4
Dependent Claim
77 words
An alumina-zirconia composite sintered product which comprises a zirconia crystalline phase composed mainly of a zirconia crystalline phase containing not larger than 4 mol% of yttrium oxide or not larger than 14 mol% of cerium oxide as a stabilizer and an alumina crystalline phase, said sintered product having such a fine structure that regions of said alumina crystalline phase being separated with the zirconia crystalline phase at a size of from 0.1 to 2 µm on average.
Claim 5
Dependent Claim
30 words
The alumina-zirconia composite sintered product according to Claim 1 or 2, wherein the content of the alumina crystalline phase is in the range of from 40 to 90% by volume.
Claim 6
Dependent Claim
133 words
The alumina-zirconia composite sintered product according to Claim 2, wherein yttrium oxide is used as a stabilizer, and the contents of the yttrium oxide and alumina are defined within a range on the lines obtained by connecting points A(45, 3.0)-B(45, 1.5)-C(85, 0.5)-D(85, 1.5)-E(54, 3.0)-A(45, 3.0) of Fig. 1 (a content of alumina in a sintered product (% by volume) and a content of yttrium oxide in zirconia (mol%)) and surrounded by the lines, and an average size of regions of the alumina crystalline phase is defined within a range on the lines obtained by connecting points a(45, 2.0)-b(50, 0.2)-c(85, 0.1)-d(85, 0.6)-a(45, 2.0) of Fig. 2 (a content of alumina in a sintered product (% by volume) and a size of the region of the alumina crystalline phase (pm)) and surrounded by the lines.
Claim 7
Dependent Claim
127 words
The alumina-zirconia composite sintered product according to Claim 2, wherein cerium oxide is used as a stabilizer, and the contents of cerium oxide and alumina are defined within a range on the lines obtained by connecting points I(50,14)-J(50,8)-K(90, 4.5)-L(90,7)-M(70,13)-I(50,14) of Fig. 3 (a content of alumina in a sintered product (% by volume) and a content of cerium oxide in zirconia (mol%)) and surrounded by the lines, and an average size of regions of the alumina crystalline phase is defined within a range on the lines obtained by connecting points i(50, 1.9)-j(50, 0.2)-k(90, 0.1)-l(90, 1.0)-i(50, 1.9) of Fig. 4 (a content of alumina in a sintered product (% by volume) and a size of the region 6f the alumina crystalline phase (pm)) and surrounded by the lines.
Claim 8
Dependent Claim
67 words
The alumina-zirconia composite sintered product according to any of Claims 1 to 5, wherein an average composition in a fine rectangular region having one side which is ten times an average of regions of the alumina crystalline phase in said composite sintered product is scattered, at any portion of said composite sintered product, within 20% of an average composition of the entirety of the composite sintered product.
Claim 9
Dependent Claim
15 words
The alumina-zirconia composite sintered product according to Claim 6, wherein the scattering is within 10%.
Claim 10
Independent Claim
76 words
A method for preparing an alumina-zirconia composite powder which comprises dispersing a-alumina par- tides having an average particle size of from 0.1 µm to 2 µm in a zirconia sol having a zirconia dispersed phase having an average particle size of not larger than 0.1 pm, subjecting the resulting mixed dispersion to dehydration to obtain a dried matter, and calcining the dried matter to obtain a mixed powder of crystalline zirconia particles and the a-alumina particles.
Claim 11
Independent Claim
76 words
A method for preparing an alumina-zirconia composite powder which comprises dispersing a-alumina par- tides having an average particle size of from 0.1 µm to 2 µm in a zirconia sol having a zirconia dispersed phase having an average particle size of not larger than 0.1 pm, subjecting the resulting mixed dispersion to dehydration to obtain a dried matter, and calcining the dried matter to obtain a mixed powder of crystalline zirconia particles and the a-alumina particles.
Claim 12
Independent Claim
20 words
The method according to Ciaim-8 7 wherein the dried matter is calcined at a temperature of from 500 to 1300°C.
Claim 13
Independent Claim
20 words
The method according to Ciaim-8 7 wherein the dried matter is calcined at a temperature of from 500 to 1300°C.
Claim 14
Dependent Claim
44 words
A method for making an alumina-zirconia composite sintered product which comprises shaping a mixed powder of crystalline zirconia particles and a-alumina particles obtained by the method defined in Claim 8 or 9 and sintering the shaped powder to obtain an alumina-zirconia composite sintered product.
Claim 15
Dependent Claim
67 words
The method according to Claim 10, wherein a sintered product obtained at a temperature of from 1300°C to 1600°C at normal pressure is subjected to hot isotactic pressing in an inert gas or in a mixed gas of oxygen and an inert gas at a temperature of from 1200 to 1600°C, provided that the treatment temperature is not higher than that used in the normal pressure sintering.
References Cited (Backward Citations)
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