Title:
METHOD FOR PRODUCING MAGNETIC DISK AND METHOD FOR PRODUCING GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM
Document Type and Number:
WIPO Patent Application WO/2011/136027
Kind Code:
A1
Abstract:
Disclosed is a method for producing a magnetic disk, by which a magnetic recording layer can be formed at high temperatures. Specifically disclosed is a method for producing a magnetic disk, which comprises a step wherein a magnetic recording layer is formed on a glass substrate that is at a temperature of 550˚C or more. The glass substrate contains, in mole percentage, 62-74% of SiO2, 6-18% of Al2O3, 2-15% of B2O3, and 8-21% in total of one or more components selected from among MgO, CaO, SrO and BaO, and the total of the contents of the above-mentioned seven components is not less than 95% by mole. The magnetic disk contains one or more components selected from among Li2O, Na2O and K2O in an amount of less than 1% by mole, or does not contain any one of the three components.
Inventors:
NAKASHIMA, Tetsuya (Limited 12-1, Yurakucho 1-chome, Chiyoda-k, Tokyo 05, 〒1008405, JP)
Application Number:
JP2011/059212
Publication Date:
November 03, 2011
Filing Date:
April 13, 2011
Export Citation:
Assignee:
ASAHI GLASS COMPANY, LIMITED (5-1 Marunouchi 1-chome, Chiyoda-ku Tokyo, 05, 〒1008405, JP)
旭硝子株式会社 (〒05 東京都千代田区丸の内一丁目５番１号 Tokyo, 〒1008405, JP)
旭硝子株式会社 (〒05 東京都千代田区丸の内一丁目５番１号 Tokyo, 〒1008405, JP)
International Classes:
G11B5/851; C03C3/091; G11B5/73
Attorney, Agent or Firm:
SENMYO, Kenji et al. (4th Floor, SIA Kanda Square 17, Kanda-konyacho, Chiyoda-k, Tokyo 35, 〒1010035, JP)
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Claims:
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