Aluminum alloy plate for magnetic disks, aluminum alloy blank for magnetic disks, aluminum alloy substrate for magnetic disks, and method for manufacturing aluminum alloy plate for magnetic disks

Abstract

The present invention provides an aluminum alloy plate for magnetic disks, an aluminum alloy plate blank for magnetic disks, and an aluminum alloy plate substrate for magnetic disks that can suppress thermal deformation during magnetic film sputtering. [Solution] Contains Mg: 0.1~7.0 mass%, Cr: 0.005~1.0 mass%, Si: 0.20 mass% or less, Ni: 0~0.85 mass% or less, with a total of at least one of Fe, Mn, and Ni: 0.05~3.25 mass%, the remainder being Al and impurities, and has a coefficient of linear expansion of 26.0 × 10⁻⁶ -6 An aluminum alloy plate for magnetic disks, having a temperature of 1 / °C or less and a stress relaxation rate of 90% or less.

Claims

1. Mg: 0.1 to 7.0% by mass, Contains Cr: 0.005 to 1.0% by mass, Si: 0.20% by mass or less, Ni: 0 to 0.85% by mass or less, The total amount of at least one of Fe, Mn, and Ni is 0.05 to 3.25% by mass. The remainder consists of Al and impurities. The coefficient of linear expansion is 26.0 × 10⁻⁶ －６ (1 / °C) or less, An aluminum alloy plate for magnetic disks with a stress relaxation rate of 90% or less.

2. The aforementioned Fe: 0 to 1.00% by mass, The aluminum alloy plate for magnetic disks according to claim 1, comprising at least one of the above Mn: 0 to 1.4% by mass.

3. Furthermore, Be: 3 to 100 ppm by mass, Cu: 1.0% by mass or less, An aluminum alloy plate for magnetic disks according to claim 1 or 2, containing at least one of Zn: 1.0% by mass or less.

4. An aluminum alloy blank for magnetic disks obtained from an aluminum alloy plate for magnetic disks according to claim 1 or 2.

5. An aluminum alloy blank for a magnetic disk obtained from an aluminum alloy plate for a magnetic disk as described in claim 3.

6. An aluminum alloy substrate for magnetic disks obtained from an aluminum alloy blank for magnetic disks according to claim 4.

7. A method for manufacturing an aluminum alloy plate for a magnetic disk according to claim 1 or 2, A casting process in which molten aluminum alloy is cast into an aluminum alloy ingot using a semi-continuous casting method, The process involves surface machining the aluminum alloy ingot and then subjecting it to a homogenization heat treatment, A hot rolling process to obtain a hot-rolled plate by hot-rolling the aluminum alloy ingot that has undergone the homogenization heat treatment, The process includes, in this order, a cold rolling step in which the hot-rolled sheet is cold-rolled, A method for manufacturing an aluminum alloy plate for a magnetic disk, wherein the value of the rolling ratio of the initial cold rolling in the cold rolling process and the total amount of Fe, Mn, and Ni satisfy the relationship shown in formula (1) below. 0 < C- R / 100 Formula (1) (In formula (1), C is the total amount (mass%) of Fe, Mn, and Ni among the components contained in the alloy, and R is the rolling rate (%) of the initial rolling in the cold rolling process.)

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