Title:
GLASS SUBSTRATE FOR MAGNETIC RECORDING MEDIUM, AND MAGNETIC RECORDING MEDIUM
Document Type and Number:
WIPO Patent Application WO/2017/119147
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a glass substrate for a magnetic recording medium such that the aggravation of flatness affected by thermal treatment can be minimized. The present invention provides a glass substrate for a magnetic recording medium comprising a glass material having an internal friction of 0.01 or less at 350°C or below. (Provided that the internal friction is calculated on the basis of a change in stress measured under the condition that a sample comprising the glass material worked into a plate shape having a length of 60 mm, a width of 5 mm, and a thickness of 0.5 mm is supported from the bottom surface by two support parts disposed along the length direction with an supporting interval of 50 mm, and a static load of 1N is applied downward to the center of the sample while repeatedly applying and releasing pressure with an amplitude of 120 μm at a frequency of 1 Hz.)
Inventors:
SUEHARA MICHINORI (JP)
OKI SATOSHI (JP)
KUROIWA YUTAKA (JP)
OKI SATOSHI (JP)
KUROIWA YUTAKA (JP)
Application Number:
PCT/JP2016/064644
Publication Date:
July 13, 2017
Filing Date:
May 17, 2016
Export Citation:
Assignee:
ASAHI GLASS CO LTD (JP)
International Classes:
G11B5/73; G11B5/84
Domestic Patent References:
| WO2011136027A1 | 2011-11-03 |
Foreign References:
| JP2001266329A | 2001-09-28 | |||
| JP2013168193A | 2013-08-29 | |||
| JP2012126625A | 2012-07-05 | |||
| JPH0641703A | 1994-02-15 | |||
| JPS60259931A | 1985-12-23 |
Attorney, Agent or Firm:
EIKOH PATENT FIRM, P.C. (JP)
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