Method For Producing Magnetic Disk And Glass Substrate For Information Recording Media

A technology of glass substrate and manufacturing method, which is applied in the field of glass substrate and magnetic disk manufacturing, can solve the problems of crosstalk or the reduction of the SN ratio of the reproduced signal, and the thermal stability of magnetic particles, and achieve the effect of high specific modulus

Active Publication Date: 2017-08-11
ASAHI GLASS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, as the recording density increases, the miniaturization of magnetic particles impairs thermal stability, and crosstalk and the reduction in the SN ratio of reproduced signals become problems.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0077] Prepare the SiO with Table 1 2 7 types of glasses with compositions expressed in mole percent in the column of -BaO. In addition, MgCa in Table 1 is the sum of the contents of MgO and CaO, and RO is the sum of the contents of MgO, CaO, SrO, and BaO. For these glasses, the density d (unit: g / cm 3 ), annealing point T A (unit: ℃), Young's modulus E (unit: GPa), specific modulus E / d (unit: MNm / kg), viscosity up to 10 4 Temperature T at dPa·s 4 (unit: ℃), the viscosity reaches 10 2 Temperature T at dPa·s 2 (unit: ℃), devitrification temperature (unit: ℃), acid resistance index A, alkali resistance index B.

[0078] The above measurement was performed as follows.

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PUM

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Abstract

The present invention provides a method for producing a magnetic disk, which is capable of forming a magnetic recording layer at high temperature. The present invention relates to 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 DEG C or more, and in which the glass substrate contains, in mol%, 60-75% of SiO2, 7-17% of Al2O3, 0% or more but less than 2% of B2O3, and one or more substances selected from among MgO, CaO, SrO and BaO in an amount of more than 18% but 26% or less in total, with the total of the above-mentioned seven components being 95% or more, while containing one or more substances selected from among Li2O, Na2O and K2O in an amount of less than 1% or not containing any of these three substances.

Description

[0001] This application is a divisional application of a Chinese patent application with a filing date of May 31, 2013, an international application number of PCT / JP2013 / 065285, and a Chinese application number of 201380029770.2. technical field [0002] The present invention relates to a method of manufacturing a magnetic disk and a glass substrate for an information recording medium, particularly a method of manufacturing a magnetic disk in which a magnetic recording layer is formed at a high temperature, and a glass substrate suitable for the manufacturing method. Background technique [0003] In recent years, along with the increase in the recording capacity of hard disk drives, higher recording densities are rapidly progressing. However, miniaturization of magnetic particles impairs thermal stability along with higher recording density, and crosstalk and reduction in the S / N ratio of reproduced signals have become problems. [0004] Therefore, heat-assisted magnetic rec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C3/085C03C3/087C03C3/091G11B5/73G11B5/84
CPCC03C3/085C03C3/087C03C3/091G11B5/7315G11B5/8404G11B5/73921
Inventor 中岛哲也辻村知之西泽学小池章夫
Owner ASAHI GLASS CO LTD
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