US5075267A
Expired / Lapsed
US
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Light transmitting yttria sintered body and its preparation
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1990-03-02
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Granted: 1991-12-24
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Expires: 2010-03-02
Abstract
Abstract A light transmitting yttria sintered body having good light transmission, can be prepared by a method of preparing a light transmitting yttria sintered body which comprises steps of densifying yttria powder having purity of not lower than 99.9% and a BET specific surface area of not smaller than 10 m 2 /g by a hot press at a temperature of 1300° to 1700° C. under a pressure of 100 to 500 kg/cm 2 in a vacuum circumstance so as to achieve the theoretical density ratio of not lower than 95% and then hot isotropically pressing densified yttria at a temperature of 1400° to 1900° C. under a pressure of not lower than 500 kg/cm 2 .
Inventors
- 👤 Akihito Fujii
- 👤 Kenichiro Shibata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:55
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/6455; C04B35/50; C04B35/505
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
95 words
A light transmitting yttria sintered body which comprises a polycrystalline yttria sintered body having purity of not lower than 99.9%, said body having a grain size of not larger than 30 μm, and wherein said body has a straight transmission of not lower than 75% on the average with the visible and near infrared light having a wavelength of 0.4 to 3 μm and a straight transmission of not lower than 80% with the medium infrared light having a wavelength of 3 to 6 μm when a yttria sample has a thickness of 3 mm.
Claim 2
Dependent Claim
95 words
A light transmitting yttria sintered body which comprises a polycrystalline yttria sintered body having purity of not lower than 99.9%, said body having a grain size of not larger than 30 μm, and wherein said body has a straight transmission of not lower than 75% on the average with the visible and near infrared light having a wavelength of 0.4 to 3 μm and a straight transmission of not lower than 80% with the medium infrared light having a wavelength of 3 to 6 μm when a yttria sample has a thickness of 3 mm.
Claim 3
Independent Claim
140 words
A method of preparing a light transmitting yttria sintered body from yttria powder which possesses a purity of greater than 99.9% and a BET specific surface are of 10 m 2 /g, said method comprising the following steps: (a) subjecting said yttria powder to a densifying treatment by a hot press comprising heating the yttria to a temperature of 1300° to 1700° C. under a pressure of 100 to 500 kg/cm 2 in the presence of a vacuum; wherein the yttria sintered body formed by said hot pressing process provides a yttria body with a theoretical density ratio of not lower than 95% ; and (b) treating said formed yttria body by providing a further densification treatment of hot isotropic pressing at a temperature of 1400° to 1900° C. under a pressure of not lower than 500 kg/cm 2 .
Claim 4
Independent Claim
140 words
A method of preparing a light transmitting yttria sintered body from yttria powder which possesses a purity of greater than 99.9% and a BET specific surface are of 10 m 2 /g, said method comprising the following steps: (a) subjecting said yttria powder to a densifying treatment by a hot press comprising heating the yttria to a temperature of 1300° to 1700° C. under a pressure of 100 to 500 kg/cm 2 in the presence of a vacuum; wherein the yttria sintered body formed by said hot pressing process provides a yttria body with a theoretical density ratio of not lower than 95% ; and (b) treating said formed yttria body by providing a further densification treatment of hot isotropic pressing at a temperature of 1400° to 1900° C. under a pressure of not lower than 500 kg/cm 2 .
Claim 5
Dependent Claim
197 words
A light transmitting yttria sintered body which possesses a purity of not lower than 99.9%, a grain size of no larger than 30 μm, and has a straight transmission of not lower than 75% on the average for visible and near infrared light having a wavelength of 0.4 to 3 μm and a straight transmission of not lower than 80% with the medium infrared light having a wavelength of 3 to 6 μm when the yttria body possesses a thickness of 3 mm; wherein said yttria body is formed by the process which comprises the following steps; (a) subjecting said yttria powder to a densifying treatment by a hot press comprising heating the yttria to a temperature of 1300° to 1700° C. under a pressure of 100 to 500 kg/cm 2 in the presence of a vacuum; wherein the yttria sintered body formed by said hot pressing process provides a yttria body with a theoretical density ratio of not lower than 95%; and (b) treating said formed yttria body by providing a further densification treatment of hot isotropic pressing at a temperature of 1400° to 1900° C. under pressure of not lower than 500 kg/cm 2 .
Claim 6
Dependent Claim
197 words
A light transmitting yttria sintered body which possesses a purity of not lower than 99.9%, a grain size of no larger than 30 μm, and has a straight transmission of not lower than 75% on the average for visible and near infrared light having a wavelength of 0.4 to 3 μm and a straight transmission of not lower than 80% with the medium infrared light having a wavelength of 3 to 6 μm when the yttria body possesses a thickness of 3 mm; wherein said yttria body is formed by the process which comprises the following steps; (a) subjecting said yttria powder to a densifying treatment by a hot press comprising heating the yttria to a temperature of 1300° to 1700° C. under a pressure of 100 to 500 kg/cm 2 in the presence of a vacuum; wherein the yttria sintered body formed by said hot pressing process provides a yttria body with a theoretical density ratio of not lower than 95%; and (b) treating said formed yttria body by providing a further densification treatment of hot isotropic pressing at a temperature of 1400° to 1900° C. under pressure of not lower than 500 kg/cm 2 .
Claim 7
Dependent Claim
35 words
The method according to claim 1, wherein at least one gas selected from the group consisting of an inert gas, a nitrogen gas and an oxygen gas is used in the hot isotropic pressing treatment.
References Cited (Backward Citations)
US3545987A
Cited
US3764643A
Cited
DE2342910A1
Cited
US3873657A
Cited
US4115134A
Cited
US4166831A
Cited
US4761390A
Cited
EP0277811A2
Cited
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