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

A technology for information recording and media substrates, applied in magnetic recording, information storage, data recording, etc., which can solve the problems of increasing the number of manufacturing processes, deteriorating glass quality, and rising costs

Inactive Publication Date: 2010-10-13
ASAHI GLASS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are problems in that chemical strengthening treatment increases the number of manufacturing steps, leading to an increase in cost, and the surface of the substrate is easily contaminated by chemical strengthening treatment
Due to the above phenomenon, non-uniform defects such as streaks are generated, which deteriorates the quality of the gla...

Method used

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  • Glass for information recording medium substrate, glass substrate for information recording medium and magnetic disk
  • Glass for information recording medium substrate, glass substrate for information recording medium and magnetic disk
  • Glass for information recording medium substrate, glass substrate for information recording medium and magnetic disk

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 122

[0123] Table 1

[0124] Example

1

2

3

4

5

6

7

8

SiO 2

66.0

66.0

66.0

66.0

65.0

64.0

66.0

66.0

Al 2 O 3

5.5

5.5

5.5

5.5

6.5

7.5

5.5

5.5

Li 2 O

8.4

8.4

8.4

8.4

8.4

8.4

5.5

6.5

Na 2 O

4.0

4.0

4.0

4.0

5.0

5.0

6.9

4.0

K 2 O

4.6

4.6

4.6

4.6

4.6

4.6

4.6

6.5

MgO

8.0

8.0

8.0

8.0

8.0

8.0

8.0

8.0

TiO 2

2.0

0

3.5

1.0

0

0

1.0

1.0

ZrO 2

1.5

3.5

0

2.5

2.5

2.5

2.5

2.5

R 2 O

17.0

17.0

17.0

17.0

18.0

18.0

17.0

17.0

Li 2 O / R 2 O

0.49

0.49

0.49

0.49

0.47

0.47

0.32

0.38

Na 2 O / R 2 O

0.24

0.24

0.24

0.24

0.28

0.28

0.41

0.24

K 2 O / R 2 O

0.27

0.27

0.27

0.27

0.26

0.26

0.27

0.38

d

2.50

2.53

2.47

2.51

2.51

2.52

2.52

2.51

α

69

69

73

69

73

72

75

73

E

83.5

85.7

83.6

84.2

83.3

83.8

81.7

82.2

[0125] Example

1

2

3

4

5

6

7

8

Tg

534

545

523

540

532

540

543

546

TL

1000

≥1150

1000

1100

≤1050

E / d

33.4

33.9

33.8

33.5

33.2

...

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PUM

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Abstract

To provide glass for an information recording medium substrate, which is excellent in the acid resistance and weather resistance. Glass for an information recording medium substrate, which comprises, as represented by mol % based on the following oxides, from 61 to 72% of SiO2, from 3 to 12% of Al2O3, from 0 to 14.3 of Li2O, from 0 to 22% of Na2O, from 0 to 22% of K2O, from 4 to 13% of MgO, from 0 to 6% of TiO2 and from 0 to 5% of ZrO2, provided that the total content of Li2O, Na2O and K2O (R2O) is from 8 to 22%, the ratio of the content of Li2O to R2O (Li2O/R2O) is at most 0.52, the ratio of the content of Na2O to R2O (Na2O/R2O) is at least 0.35, or the ratio of the content of K2O to R2O (K2O/R2O) is at least 0.45.

Description

Technical field [0001] The present invention relates to glass used for information recording medium substrates such as magnetic disks (hard disks), glass substrates for information recording media, and magnetic disks. Background technique [0002] Glass substrates are widely used as substrates for information recording media, especially magnetic disks. A commercially available glass substrate is known. The composition of the glass substrate is expressed in mol% and contains 65.4% SiO 2 , 8.6% Al 2 O 3 , 12.5% ​​Li 2 O, 10.5% Na 2 O and 3.0% ZrO 2 . The commercially available glass is chemically strengthened for use. [0003] On the other hand, Patent Document 1 proposes a substrate glass for a magnetic disk that has not undergone a chemical strengthening treatment. [0004] Patent Document 1: JP-A-2002-358626 (Tables 1-14) [0005] A low-pH acid is used in the polishing or washing process of the glass substrate for magnetic disks. Therefore, the glass substrate for magnetic disks is ...

Claims

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Application Information

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IPC IPC(8): C03C3/083C03C3/085C03C3/091C03C3/093C03C15/00C03C17/00G11B5/62
CPCC03C3/085C03C3/087G11B5/7315G11B5/73921
Inventor 远藤淳长嶋达雄中岛哲也M·D·雷耶斯
Owner ASAHI GLASS CO LTD
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