Aluminum alloy substrate used for magnetic disc, and method of manufacturing the same

A technology for aluminum alloy substrates and magnetic disks, applied in the direction of the magnetic recording layer, the base layer of the recording layer, etc., can solve the problems of flatness deterioration, substrate deformation, plating surface roughening, etc., and achieve the purpose of suppressing the deterioration of flatness and crystal effect of grain coarsening

Active Publication Date: 2012-05-23
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0022] However, the JIS5086 alloy used in the past and the aluminum alloy substrates for magnetic disks described in Patent Documents 1 to 4 do not cause any problems in the sputtering of magnetic materials at a temperature below 300°C, but if the sputtering of magnetic materials at 500°C Sputtering, there are problems such as deformation of the substrate, deterioration of flatness, or roughening of the plated surface due to coarsening of crystal grains.

Method used

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  • Aluminum alloy substrate used for magnetic disc, and method of manufacturing the same
  • Aluminum alloy substrate used for magnetic disc, and method of manufacturing the same
  • Aluminum alloy substrate used for magnetic disc, and method of manufacturing the same

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no. 1 approach

[0042] First, a first embodiment of the aluminum alloy substrate for a magnetic disk of the present invention will be described.

[0043] Change in flatness before and after heating at 500° C. for 10 seconds in the aluminum alloy substrate for a magnetic disk according to the first embodiment, which contains Mg at 3.5 mass % or more and 6 mass % or less, and the balance is composed of Al and unavoidable impurities 5 μm or less, and the change amount of the average crystal grain diameter before and after heating at 500° C. for 10 seconds was 10 μm or less.

[0044] Here, the aforementioned "heating at 500° C. for 10 seconds" is, for example, a condition for simulating the sputtering of a magnetic material suitable for heat-assisted magnetic recording. Heat treatment performed by stacking and annealing (straightening annealing) the flatness-corrected aluminum alloy substrates for magnetic disks of the present invention. Therefore, "before and after heating at 500° C. for 10 sec...

no. 2 approach

[0064] Next, a second embodiment of the aluminum alloy substrate for a magnetic disk of the present invention will be described.

[0065] The aluminum alloy substrate for a magnetic disk according to the second embodiment contains Mg at 3.5 mass % or more and 6 mass % or less, and contains Cr at 0.05 mass % or more, Mn at 0.05 mass % or more, and Zr at 0.05 mass % or more At least one selected, the balance consisting of Al and unavoidable impurities, the amount of change in flatness before and after heating at 500°C for 10 seconds is 5 μm or less, and the average grain size before and after heating at 500°C for 10 seconds The amount of change in diameter is 10 μm or less.

[0066] In addition, the aluminum alloy substrate for a magnetic disk according to the second embodiment contains 3.5% by mass to 6% by mass of Mg, and the balance is composed of Al and unavoidable impurities, and the flatness before and after heating at 500° C. for 10 seconds The amount of change in degree...

no. 3 approach

[0071] Next, a third embodiment of the aluminum alloy substrate for a magnetic disk of the present invention will be described.

[0072] The aluminum alloy substrate for a magnetic disk according to the third embodiment contains Mg at 3.5 mass % to 6 mass %, Cr at 0.05 mass % to 0.3 mass %, and Mn at 0.05 mass % to 0.5 mass % , and Zr is at least one selected from the group of 0.05% by mass to 0.5% by mass, and contains the group of Cu of 0.01% by mass to 0.2% by mass and Zn of 0.01% by mass to 0.4% by mass At least one selected from among, the balance is composed of Al and unavoidable impurities, and among the unavoidable impurities, Si is limited to 0.03 mass % or less, Fe is limited to 0.05 mass % or less, and heated at 500 ° C The amount of change in flatness before and after 10 seconds was 5 μm or less, and the amount of change in average grain diameter before and after heating at 500° C. for 10 seconds was 10 μm or less.

[0073]In addition, the aluminum alloy substrate...

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Abstract

The invention provides an aluminum alloy substrate used for magnetic discs, and a method of manufacturing the same. Even if an aluminum alloy substrate is heated to be as high as 500 DEG C, worsening of smoothness and thickening of crystalline grains are prevented. The aluminum alloy substrate comprises 3.5% to 6% by mass of Mg, balance being Al and unavoidable impurities. The variable quantity of the smoothness of the aluminum alloy substrate before and after heating within 10 seconds at a tempetature of 500 DEG C is below 5um, and the variable quantity of the average grain diameter of the aluminum alloy substrate before and after heating within 10 seconds at a tempetature of 500 DEG C is below 10um. According to the method of manufacturing the aluminum alloy substrate used for magnetic discs, pack annealing of the aluminum alloy substrate used for magnetic discs includes the steps of holding the substrate for more than two hours at a temperature of more than 350 DEG C under a condition that the temperature rises into over 350 DEG C at a speed of 2 DEG C per minute, and cooling at a cooling speed of below 2 DEG C per minute.

Description

technical field [0001] The invention relates to an aluminum alloy substrate for a magnetic disk and a manufacturing method thereof. Background technique [0002] A magnetic disk used as a recording medium of a computer or the like is formed by attaching a magnetic film to a nonmagnetic substrate. Generally, the substrate is required to be lightweight, have high rigidity, and have a smooth surface. Therefore, an aluminum alloy plate is used for reasons such as being non-magnetic, lightweight, and easy to obtain a smooth surface through mirror processing, etc., and formed on its surface. Used to obtain a rigid Ni-P coating to a thickness of about 10 μm, which becomes a substrate for a magnetic disk. [0003] Conventionally, as such an aluminum alloy plate, the 5086 alloy (Al-Mg alloy) stipulated in JISH4000 can be used because it has sufficient strength required for impact resistance for hard disk drives and can obtain sufficient surface smoothness. . [0004] In addition, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C21/06C22F1/047G11B5/73
Inventor 梅田秀俊寺田佳织
Owner KOBE STEEL LTD
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