US5874378A
Expired / Lapsed
US
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Sintered aluminum nitride
Assignee: Kyocera Corp
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Filing: 1997-06-23
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Granted: 1999-02-23
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Expires: 2017-06-23
Abstract
Abstract A sintered aluminum nitride contains rare earth elements (RE) in amounts of from 3 to 10% by weight in terms of RE2O3, alkaline earth elements (R) in amounts of from 0.3 to 3.0% by weight in terms of RO, and silicon atoms in an amount of from 0.3 to 1.0% by weight in terms of SiO2, the grain boundaries of AlN crystals being chiefly a YAG type crystalline phase. The sintered product is obtained by firing at a temperature as low as 1700 DEG C. or lower, has a thermal conductivity of not smaller than 60 W/m.K, loses weight in an amount of not more than 10 mg/cm2 when it is left to stand in a 4N NaOH aqueous solution maintained at 70 DEG C. for one hour, and exhibits excellent resistance against the alkalis.
Inventors
- 👤 Masanobu Ishida
- 👤 Toshihiro Iwaida
- 👤 Hiroshi Okayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:40
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/581; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0306
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
185 words
A sintered aluminum nitride comprising: aluminum nitride (AlN); rare earth elements (RE) in amounts from 3 to 10% by weight in terms of Re 2 O 3 ; alkaline earth elements (R) in amounts of from 0.3 to 3.0% by weight in terms RO; and silicon atoms in an amount of from 0.3 to 1.0% by weight in terms of SIO 2 ; wherein the alkaline earth elements consist of Mg and at least one of Ca and Sr, Mg is present in an amount of from 0.05 to 1.0% by weight in terms of MgO, and Ca is present in an amount of from 0.1 to 1.0% by weight in terms of CaO; a YAG type crystalline phase precipitated on grain boundaries of AlN crystals; and further wherein the sintered aluminum nitride has a thermal conductivity of not smaller than 60 W/m•K; and when the sintered aluminum nitride is left to stand in a 4N NaOH aqueous solution maintained at 70° C. for one hour, the weight loss per surface area of the sintered aluminum nitride is not more than 10 mg/cm 2 .
Claim 2
Dependent Claim
185 words
A sintered aluminum nitride comprising: aluminum nitride (AlN); rare earth elements (RE) in amounts from 3 to 10% by weight in terms of Re 2 O 3 ; alkaline earth elements (R) in amounts of from 0.3 to 3.0% by weight in terms RO; and silicon atoms in an amount of from 0.3 to 1.0% by weight in terms of SIO 2 ; wherein the alkaline earth elements consist of Mg and at least one of Ca and Sr, Mg is present in an amount of from 0.05 to 1.0% by weight in terms of MgO, and Ca is present in an amount of from 0.1 to 1.0% by weight in terms of CaO; a YAG type crystalline phase precipitated on grain boundaries of AlN crystals; and further wherein the sintered aluminum nitride has a thermal conductivity of not smaller than 60 W/m•K; and when the sintered aluminum nitride is left to stand in a 4N NaOH aqueous solution maintained at 70° C. for one hour, the weight loss per surface area of the sintered aluminum nitride is not more than 10 mg/cm 2 .
Claim 3
Dependent Claim
64 words
A sintered aluminum nitride according to claim 1, further comprising at least one of W or Mo in an amount of from 0.05 to 0.5% by weight in terms of at least one of WO 3 or MoO 3 , and the sintered aluminum nitride has a brightness index L* of not larger than 50 and a chroma C* of not larger than 2.
Claim 4
Dependent Claim
40 words
A sintered aluminum nitride according to claim 1, which is obtained by firing a material containing aluminum nitride, rare earth elements, alkaline earth elements and silicon atoms at a temperature of not higher than 1700° C. in a nitrogen-containing atmosphere.
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