Title:
MAGNETIC DISK SUBSTRATE AND METHOD FOR MANUFACTURING SAME, AND MAGNETIC DISK
Document Type and Number:
WIPO Patent Application WO/2023/027140
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a magnetic disk substrate and a method for manufacturing same, and a magnetic disk all of which make it possible to maintain high flatness, despite being thin, after a long-term use, be compatible with a high capacity of hard disk, and improve long-term reliability thereof. In a magnetic disk substrate according to the present invention, when a process for heating a substrate at 120℃ for 30 minutes and then cooling the substrate at -40℃ for 30 minutes is defined as one cycle, the flatness PV of a surface of the substrate measured at 25℃ after a thermal impact test in which the cycle is repeatedly performed 200 times is not more than 12 μm. The present invention further encompasses a magnetic disk having a similar flatness PV under the same conditions. The present invention still further encompasses a method for manufacturing the magnetic disk substrate.
More Like This:
Inventors:
HATAKEYAMA HIDEYUKI (JP)
TAKIGUCHI KOICHIRO (JP)
TAKIGUCHI KOICHIRO (JP)
Application Number:
PCT/JP2022/032021
Publication Date:
March 02, 2023
Filing Date:
August 25, 2022
Export Citation:
Assignee:
FURUKAWA ELECTRIC CO LTD (JP)
UACJ CORP (JP)
UACJ CORP (JP)
International Classes:
G11B5/73; B24B1/00; B24B37/08; G11B5/02; G11B5/82; G11B5/84
Domestic Patent References:
| WO2013047190A1 | 2013-04-04 | |||
| WO2013046583A1 | 2013-04-04 | |||
| WO2014156189A1 | 2014-10-02 |
Attorney, Agent or Firm:
KURUMA Kiyoshi et al. (JP)
Download PDF: