Glass for information recording media substrate, glass substrate for magnetic disk and magnetic disk

A technology for information recording and glass substrates, which is applied in the fields of glass substrates for information recording media, glass substrates for magnetic disks, and magnetic disks. It can solve problems such as the disappearance of recorded information and the decline in the reliability of recording media, reduce motor load, and solve dirt adhesion. Problems, the effect of high acid resistance

Inactive Publication Date: 2009-04-29
ASAHI GLASS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In addition, if the alkali metal component diffuses into the magnetic film, the recorded information is likely to disappear, so there is a problem that the reliability of the recording medium is significantly reduced. Among them, Na is considered to be the most likely to diffuse into the magnetic film.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0062] SiO according to the table 2 to ZrO 2 The raw materials of each component are adjusted to the composition expressed in mol% in the column of , and melted at a temperature of 1550-1600° C. for 3-5 hours in a platinum crucible. During melting, a platinum stirrer was inserted into the molten glass and stirred for 2 hours to homogenize the glass. Then, the molten glass was flow-formed into a flat plate, and annealed to room temperature at a cooling rate of 1° C. per minute. Al+Mg+Ti in the table means Al 2 o 3 , MgO and TiO 2 The total of each content (unit: mole %), R 2 O stands for Li 2 O, Na 2 O and K 2 The total of the contents of O (unit: mol %).

[0063] The glasses of Examples 1 to 31 are examples, and the glasses of Examples 32 to 41 are comparative examples. The glass of Example 32 is the same glass as the commercially available chemically strengthened glass, and the glass of Example 33 is a chemically strengthened glass.

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PUM

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Abstract

To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO2, from 11.5 to 17% of Al2O3, from 8 to 16% of Li2O, from 2 to 8% of Na2O, from 2.5 to 8% of K2O, from 0 to 6% of MgO, from 0 to 4% of TiO2 and from 0 to 3% of ZrO2, provided that Al2O3+MgO+TiO2 is at least 12%, and Li2O+Na2O+K2O is from 16 to 23%, wherein in a case of where B2O3 is contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120 DEG C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as CLi, CNa and CK respectively, CNa is at most 0.7 nmol/cm2, and CLi+CNa+CK is at most 3.5 nmol/cm2.

Description

technical field [0001] The present invention relates to glass used for substrates of information recording media such as magnetic disks (hard disks), glass substrates for magnetic disks, and magnetic disks. Background technique [0002] Glass substrates are widely used as substrates for information recording media, especially for magnetic disks, and it is known that the composition expressed in mol% contains 65.4% of SiO 2 , 8.6% Al 2 o 3 , 12.5% ​​Li 2 O, 10.5% Na 2 O, 3.0% ZrO 2 commercially available glass. This commercially available glass was used after chemical strengthening treatment. [0003] On the other hand, Patent Document 1 discloses a substrate glass for a magnetic disk that has not been chemically strengthened. [0004] [Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-358626 (Tables 1 to 14) Contents of the invention [0005] As a glass substrate for a magnetic disk, it is required that its surface properties do not change significa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C3/093C03C3/085
Inventor 中岛哲也前田敬下平宪昭竹中敦义
Owner ASAHI GLASS CO LTD
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