Title:
LIGHT−EMITTING CASE FOR HIGH−VOLTAGE DISCHARGE LUMP AND METHOD FOR PREPARATION OF POLYCRYSTALLINE TRANSPARENT ALUMINA SINTERED ARTICLE
Document Type and Number:
WIPO Patent Application WO/2003/075312
Kind Code:
A1
Abstract:
A method for preparing a polycrystalline transparent alumina sintered article, which comprises admixing an alumina having a purity of 99.9 % or higher with MgO in the range of 0.002 to 0.010 wt % and La2O3 in the range of 0.005 to 0.020 wt % in a manner such that the sum of MgO and La2O3 is 0.030 wt % or less and the relationship: 0.2 ≤ MgO&sol La2O3 ≤ 0.5 is satisfied, calcinating the resultant mixture at 900 to 1200&ring C, subjecting the calcinated product to a slip casting, subjecting the cast product to a chelating treatment, and holding the chelated product at 1650 to 1900&ring C in a reducing atmosphere for 1 hr or more, to thereby fire it under a normal pressure. A polycrystalline transparent alumina sintered article prepared by the method is optimized in the types and the amounts of sintering aids for the use in a light−emitting case of a high−voltage discharge lump.
Inventors:
ASANO OSAMU
Application Number:
PCT/JP2002/002114
Publication Date:
September 12, 2003
Filing Date:
March 07, 2002
Export Citation:
Assignee:
NGK INSULATORS LTD (JP)
International Classes:
C04B35/115; H01J9/24; H01J61/30; (IPC1-7): H01J61/30; H01L9/24; C04B35/10
Foreign References:
| JP2000219570A | 2000-08-08 | |||
| JPS58121540A | 1983-07-19 | |||
| JPS53111312A | 1978-09-28 | |||
| JPS51107683A | 1976-09-24 | |||
| JPS6048466B2 | 1985-10-28 |
Attorney, Agent or Firm:
Ishida, Yoshiki (Higashisakura 1-chome Higashi-k, Nagoya-shi Aichi, JP)
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