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Substrate for information recording medium, information recording medium and process for producing the same

A technology for information recording and manufacturing methods, applied in magnetic recording, information storage, magnetic recording layers, etc., can solve problems such as increased viscosity, reduced melting, and adverse effects of information recording layers

Inactive Publication Date: 2005-08-10
HOYA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, at such a high temperature, the commercially available aluminum substrates and chemically strengthened glass substrates obviously cannot adapt, and glass substrates with high heat resistance are required.
[0006] In order to obtain excellent heat resistance, glass materials that do not use alkali metal oxides, which have been an essential component of glass for chemical strengthening, are considered, but in this case, the viscosity at the time of melting increases, causing a problem that the meltability decreases
In addition, when the disk is installed in the drive unit, the thermal expansion coefficient of the glass substrate needs to be increased in order to match the thermal expansion characteristics of the metal fixing jig used to fix the disk, but the glass without alkali metal oxides is difficult to cause thermal expansion. The coefficient is in the range required by the substrate for information recording media
[0007] On the other hand, in order to improve the meltability and thermal expansion coefficient of the glass, when alkali metal oxides are introduced, the alkali is eluted from the glass substrate, which has the problem of adversely affecting the information recording layer provided on the substrate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-16 and comparative example 1

[0103] In order to obtain glasses with the compositions shown in Table 1 to Table 3 corresponding to Glass I, SiO is used as the starting material 2 、Al 2 o 3 , Al(OH) 3 , MgO, Mg(OH) 2 , MgCO 3 , CaCO 3 , SrCO 3 、BaCO 3 , ZnO, Li 2 CO 3 、Na 2 CO 3 、K 2 CO 3 、TiO 2 and ZrO 2 etc., weigh 300-1500g, mix thoroughly to make a blended batch, put it into a platinum crucible, and melt the glass in air at a temperature of 1400-1600°C for about 3-8 hours. After melting, let the molten glass flow into a 40×40×20mm carbon mold, cool naturally to the transition point temperature of the glass, put it into the annealing furnace immediately, keep it for 1 hour, and then cool it naturally in the furnace to room temperature. The obtained glass did not precipitate crystals to the extent that it could be observed with a microscope. In addition, the obtained glass had high homogeneity, no unmelted matter was confirmed, and it was confirmed that the meltability was high.

[0104] ...

Embodiment 17-27

[0134] In order to obtain the glasses of Examples 17-27 shown in Tables 7-9 corresponding to Glass II, as a starting material, SiO 2 、Al 2 o 3 , Al(OH) 3 , CaCO 3 、BaCO 3 、Na 2 CO 3 、K 2 CO 3 、TiO 2 , ZrO 2 etc., weigh 300-1500g of glass raw materials, mix them thoroughly to make a blended batch, put it into a platinum crucible, and melt the glass in air at a temperature of 1400-1600°C for about 3-8 hours. After melting, let the molten glass flow into a 40×40×20mm carbon mold, cool naturally to the transition point temperature of the glass, put it into the annealing furnace immediately, keep it for 1 hour, and then cool it naturally in the furnace to room temperature. The resulting glass was observed with a microscope, but no crystal grains were found in the glass. In addition, the obtained glass had high homogeneity, no unmelted matter was confirmed, and it was confirmed that the meltability was high. In addition, 0.5% by weight of Sb was added to the glasses of E...

Embodiment 28

[0159] A magnetic disk of a perpendicular recording method is fabricated using a washed and dried glass substrate. Two types of perpendicular recording methods are produced: a two-layer film in which a soft magnetic layer and a magnetic recording layer are sequentially laminated when forming a magnetic recording layer, and a three-layer film in which a hard magnetic layer, a soft magnetic layer, and a magnetic recording layer are sequentially laminated. disk. In this process, the magnetic recording film is heat-treated at a high temperature of 400-600°C. Since each substrate has high heat resistance with a glass transition temperature (Tg) of 620°C or higher, the substrate does not deform and maintains high flatness.

[0160] Thus, since the glass substrate of the present invention has a high glass transition temperature, it is suitable for high-temperature processing for improving the characteristics of a magnetic recording medium and for producing a magnetic film in a high-t...

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Abstract

The invention discloses a base used for information recording media, information recording media provided with an information storage layer on the base and the manufacture method. The invention is characterized in that the base used for information recording media is composed of a glass containing alkali metal oxide; wherein, the transformation temperature of the glass is more than six hundred and twenty DEG C; when the glass is dipped into the constant temperature water with eighty DEG C for twenty four hours, the dissolved quantity of the alkali metal ions is less than zero point two Mu mo / cm <2> per unit area.

Description

technical field [0001] The present invention relates to a substrate for an information recording medium having high heat resistance and having an extremely low amount of eluted alkali metal ions despite containing an alkali metal oxide, an information recording medium including the above substrate, and a method for producing the same. In particular, it relates to a substrate for a magnetic recording medium which is very suitable for producing a magnetic film for a perpendicular magnetic recording system by a high-temperature sputtering machine, a magnetic recording medium, and a method for producing the same. Background technique [0002] Conventionally, aluminum, glass, ceramics, and the like have been used as substrate materials for magnetic recording media. Currently, mainly aluminum and glass are put into practical use according to the size and application. Among them, glass substrates have been widely used year by year because they have few surface defects and are exce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C3/087G11B5/73G11B5/84
CPCG11B5/7315Y10T428/31C03C3/087G11B5/8404G11B5/73913G11B5/73921
Inventor 池西干男邹学禄
Owner HOYA CORP
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