Invention Grant
- Patent Title: Glass substrate for information recording medium and method for manufacturing the same, and magnetic recording medium
- Patent Title (中): 用于信息记录介质的玻璃基板及其制造方法和磁记录介质
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Application No.: US12833410Application Date: 2010-07-09
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Publication No.: US08328602B2Publication Date: 2012-12-11
- Inventor: Masahiko Tamura , Toru Momose , Katsuaki Miyatani , Tetsuya Nakashima
- Applicant: Masahiko Tamura , Toru Momose , Katsuaki Miyatani , Tetsuya Nakashima
- Applicant Address: JP Tokyo
- Assignee: Asahi Glass Company, Limited
- Current Assignee: Asahi Glass Company, Limited
- Current Assignee Address: JP Tokyo
- Agency: Oblon, Spivak, McClelland, Maier & Neustadt, L.L.P.
- Priority: JP2009-162746 20090709
- Main IPC: C03B27/00
- IPC: C03B27/00 ; B24C3/08 ; G11B9/04

Abstract:
The present invention relates to a method for manufacturing a glass substrate for information recording medium, the method including: a lapping step of lapping a circular glass plate made of an alkali aluminosilicate glass; and a subsequent cerium oxide polishing step of polishing the circular glass plate with a slurry containing a cerium oxide abrasive, in which a difference (SiO2−Al2O3) obtained by subtracting an Al2O3 content from an SiO2 content in the alkali aluminosilicate glass is 62% by mole or less; and in which the method further includes: subsequently to the cerium oxide polishing step, a cleaning step of cleaning the circular glass plate with a cleaning liquid having a sulfuric acid concentration of 20% by mass or more and 80% by mass or less and a hydrogen peroxide concentration of 1% by mass or more and 10% by mass or less at a liquid temperature of 50° C. or higher and 100° C. or lower, and after the cleaning step, a finish polishing step of polishing a main surface of the circular glass plate with a slurry containing a colloidal silica abrasive.
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