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Title:
INFORMATION RECORDING MEDIUM GLASS SUBSTRATE, POLISHING COLLOIDAL SILICA SLURRY FOR MANUFACTURING THEREOF, AND INFORMATION RECORDING MEDIUM
Document Type and Number:
Japanese Patent JP2011233205
Kind Code:
A
Abstract:

To provide an information recording medium glass substrate having small Ra in a method for manufacturing the information recording medium glass substrate by passing a glass disk made of an alkaline aluminosilicate glass through a polishing step using a slurry containing colloidal silica abrasives.

A colloidal silica slurry is used in a method for manufacturing an information recording medium glass substrate, including a wrapping step of wrapping a main surface of a glass disk, a cerium oxide polishing step of executing polishing by using a slurry containing cerium oxide abrasives, and a colloidal silica polishing step of executing polishing by using a slurry containing colloidal silica abrasives. In the colloidal silica slurry, for colloidal silica abrasives, a BET particle size obtained by BET specific surface measurement is equal to or less than 40 nm, and a smoothness index represented by BET particle size (nm)/circularity is equal to or less than 50 nm. Also provided are an information recording medium glass substrate manufactured by using the colloidal silica slurry, and a magnetic recording medium having a magnetic recording layer formed on a main surface of the information recording medium glass substrate.


Inventors:
MIYATANI KATSUAKI
Application Number:
JP2010000103510
Publication Date:
November 17, 2011
Filing Date:
April 28, 2010
Export Citation:
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Assignee:
ASAHI GLASS CO LTD
International Classes:
G11B5/84; B24B1/00; B24B37/00; G11B5/73
Domestic Patent References:
JP2010041029A2010-02-18
JP2008013655A2008-01-24
JP2009050920A2009-03-12
JP2009280478A2009-12-03
JP2004055128A2004-02-19
JP2008222979A2008-09-25
JP2002283210A2002-10-03
JP2010170648A2010-08-05
JP2010041029A2010-02-18
JP2008013655A2008-01-24
JP2009050920A2009-03-12
JP2009280478A2009-12-03
JP2004055128A2004-02-19
JP2008222979A2008-09-25
JP2002283210A2002-10-03
JP2010170648A2010-08-05
Attorney, Agent or Firm:
小栗 昌平
本多 弘徳
市川 利光