Title: Glass-ceramic for a magnetic disk substrate and method for manufacturing the same
Application Number: 94108224 Application Date: 1994.07.11
Publication Number: 1114954 Publication Date: 1996.01.17
Approval Pub. Date: Granted Pub. Date: 1999.04.07
International Classifi-cation: C03C10/12
Applicant(s) Name: Kabushiki Kaisya Ohara Address:
Inventor(s) Name: Naoyuki Goto
Attorney & Agent: LU XINHUA WEI JINXI
Abstract:
     The glass ceramic used as substrate of magnetic disk with controllable grain size and polished surface roughness of 15-50 angstroms is made up by thermal treatment of glass as base material, which contains such components (wt.%) as SiO2 (65-83), Li2O (8-11), K2O (0-7), MgO ZnO PbO (0.5-5.5) where MgO (0.5-5.5), ZnO (0-4) and PbO (0-5), P2O2 (1-4), Al2O2 (0-7), and As2O3 Sb2O3 (0-2). It contains alpha-quartz (SiO2) and Li2O.2SiO2 as main crystal phase. Said alpha-quartz grain has spherical grain structure formed by aggregative particles (secondary ones).
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