US4595665A
Expired / Lapsed
US
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High alumina sintered body
Assignee: Kyocera Corp
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Filing: 1984-11-06
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Granted: 1986-06-17
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Expires: 2004-11-06
Abstract
Abstract A high alumina sintered body composed of a substrate consisting substantially of alpha -Al2O3 and a surface layer of mullite precipitated in situ on the substrate. The sintered body is obtained by molding and sintering a composition comprising a main component containing at least 75% by weight, based on the total weight of the composition, of alpha -Al2O3 and a predetermined amount of silica, a mullite mineralyzing agent and B2O3. The sintered body has a combination of excellent thermal shock resistance and mechanical properties such as flexural strength.
Inventors
- 👤 Hiroshi Takayama
- 👤 Hiroshi Maruyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:10
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B41/45; C04B41/50; C04B41/5025; C04B41/80; C04B41/81; C04B41/85; C04B41/87; Y; Y10; Y10T; Y10T428/00; Y10T428/26
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
154 words
A high alumina sintered body composed of a substrate consisting substantially of α-Al 2 O 3 and a surface layer of mullite precipitated in situ on the substrate, wherein α-Al 2 O 3 and a glass phase are present in the mullite surface layer, said sintered body being obtained by molding and sintering at a temperature at or above about 1400° C. a composition consisting essentially of 75 to 95% by weight of α-Al 2 O 3 and 3 to 10% by weight of SiO 2 as main components, 1 to 10% by weight of a mullite mineralizing agent selected from the group consisting of TiO 2 , ZrO 2 , Fe 2 O 3 , MnO 2 , MoO 2 , Ce 2 O 3 and mixtures thereof 0.3 to 1% by weight of B 2 O 3 , and 0.4 to 3% by weight of at least one of MgO and CaO.
Claim 2
Dependent Claim
154 words
A high alumina sintered body composed of a substrate consisting substantially of α-Al 2 O 3 and a surface layer of mullite precipitated in situ on the substrate, wherein α-Al 2 O 3 and a glass phase are present in the mullite surface layer, said sintered body being obtained by molding and sintering at a temperature at or above about 1400° C. a composition consisting essentially of 75 to 95% by weight of α-Al 2 O 3 and 3 to 10% by weight of SiO 2 as main components, 1 to 10% by weight of a mullite mineralizing agent selected from the group consisting of TiO 2 , ZrO 2 , Fe 2 O 3 , MnO 2 , MoO 2 , Ce 2 O 3 and mixtures thereof 0.3 to 1% by weight of B 2 O 3 , and 0.4 to 3% by weight of at least one of MgO and CaO.
Claim 3
Dependent Claim
84 words
The sintered body of claim 1 wherein the precipitation of mullite is effected such that the peak ratio (R I ) defined by the following equation R.sub.I =(I.sub.M /I.sub.A)×100 wherein I M represents the peak intensity of the plane index (210) of mullite in the X-ray diffraction of the mullite precipitated surface layer and I A represents the peak intensity of the plane index (012) of α-Al 2 O 3 in the X-ray diffraction of the mullite precipitated surface layer, becomes at least 30%.
Claim 4
Dependent Claim
23 words
The sintered body of claim 1 wherein its surface layer has the mullite precipitated layer having a thickness of at least 100 μm.
Claim 5
Dependent Claim
18 words
The sintered body of claim 1 which has a thermal shock temperature difference of at least 200° C.
Claim 6
Dependent Claim
18 words
The sintered body of claim 1 which has a flexural strength of at least 36 kg/mm 2 .
Claim 7
Dependent Claim
21 words
The sintered body of claim 1 wherein the ratio of SiO 2 to the mullite mineralyzing agent is at least 1.
Claim 8
Dependent Claim
22 words
The sintered body of claim 1 wherein the ratio of SiO 2 to B 2 O 3 is from 3 to 20.
Claim 9
Dependent Claim
151 words
A high alumina sintered body comprising a substrate consisting substantially of alpha alumina, the substrate having a surface layer including mullite, the surface layer mullite being precipitated in situ on the substrate surface, wherein the sintered body is produced by sintering at a temperature at or above 1400° C. a composition consisting essentially of: from about 75 to about 95% by weight of alpha alumina; from about 3 to about 10% by weight of silica; from about 1 to about 10% by weight of a mullite mineralizing agent selected from the group consisting of TiO 2 , ZrO 2 , Fe 2 O 3 , MnO 2 , MoO 2 , and Ce 2 O 3 and mixtures thereof from about 0.3 to 1% by weight of boron oxide; and from about 0.4 to 3% by weight of a sintering aid selected from the group comprising magnesium oxide and calcium oxide.
Claim 10
Dependent Claim
151 words
A high alumina sintered body comprising a substrate consisting substantially of alpha alumina, the substrate having a surface layer including mullite, the surface layer mullite being precipitated in situ on the substrate surface, wherein the sintered body is produced by sintering at a temperature at or above 1400° C. a composition consisting essentially of: from about 75 to about 95% by weight of alpha alumina; from about 3 to about 10% by weight of silica; from about 1 to about 10% by weight of a mullite mineralizing agent selected from the group consisting of TiO 2 , ZrO 2 , Fe 2 O 3 , MnO 2 , MoO 2 , and Ce 2 O 3 and mixtures thereof from about 0.3 to 1% by weight of boron oxide; and from about 0.4 to 3% by weight of a sintering aid selected from the group comprising magnesium oxide and calcium oxide.
Claim 11
Dependent Claim
18 words
A high alumina sintered body according to claim 8 wherein the substrate surface layer consists substantially of mullite.
Claim 12
Dependent Claim
38 words
A high alumina sintered body according to claim 8 wherein the substrate surface layer consists substantially of mullite, alpha alumina and a glass phase containing silica, alumina, titanium dioxide, zirconium dioxide, magnesium oxide, calcium oxide, and boron oxide.
Claim 13
Dependent Claim
29 words
A high alumina sintered body according to claim 8 wherein there is present in the composition to be sintered greater than or equal to 5% by weight silica dioxide.
Claim 14
Dependent Claim
31 words
A high alumina sintered body according to claim 8 wherein the sintering is accomplished within an oxidizing atmosphere and wherein the sintering temperature is from about 1400° to about 1700° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |