Aluminum alloy sheet for magnetic disk and production method therefor, and magnetic disk using said aluminum alloy sheet for magnetic disk

Patent metadata

Field	Value
Publication number	US-11361791-B2
Application number	US-201917262971-A
Country	US
Kind code	B2
Filing date	Jul 24, 2019
Priority date	Jul 25, 2018
Publication date	Jun 14, 2022
Grant date	Jun 14, 2022

Abstract

An aluminum alloy sheet for a magnetic disk includes an aluminum alloy comprising 0.10 to 3.00 mass % (hereafter simply “%”) of Fe, 0.1 to 3.0% of Mn, 0.003 to 1.000% of Cu, and 0.005 to 1.000 s % of Zn, wherein second phase particles having a maximum diameter of 100 μm or more and 300 μm or less are dispersed at a distribution density of 50 particles/mm2 or less in a region (A) occupying 25% or less of a sheet thickness from a sheet thickness center plane to opposite surfaces of the sheet, second phase particles having a maximum diameter of 100 μm or more and 300 μm or less are 0 particles/mm2 in a region (C) that is obtained by excluding the region (A) from a region (B) occupying 50% or less of the sheet thickness from the sheet thickness center plane to the opposite surfaces of the sheet, and the amount of Mn solid solution is 0.03 mass % or more.

First claim

The invention claimed is:

1. An aluminum alloy sheet for a magnetic disk, the aluminum alloy sheet comprising:
an aluminum alloy comprising 0.10 to 3.00 mass % of Fe, 0.1 to 3.0 mass % of Mn, 0.003 to 1.000 mass % of Cu, 0.005 to 1.000 mass % of Zn, 0.4 mass % or less of Si, and optionally one or more elements selected from a group consisting of 0.1 to 3.0 mass % of Ni, 0.1 to 6.0 mass % of Mg, 0.01 to 1.00 mass % of Cr, and 0.01 to 1.00 mass % of Zr, with a balance of Al and unavoidable impurities, wherein
second phase particles having a maximum diameter of 100 μm or more and 300 μm or less are dispersed at a distribution density of 50 particles/mm 2 or less in a region (A) occupying 25% or less of a sheet thickness from a sheet thickness center plane to opposite surfaces of the sheet,
second phase particles having a maximum diameter of 100 μm or more and 300 μm or less are 0 particles/mm 2 in a region (C) excluding the region (A) from a region (B) occupying 50% or less of the sheet thickness from the sheet thickness center plane to the opposite surfaces of the sheet, and
an amount of Mn solid solution is 0.03 to 1.00 mass %.

2. The aluminum alloy sheet according to claim 1 , wherein the aluminum alloy further comprises one or more elements selected from a group comprising Ti, B, and V, of which a total content is 0.005 to 0.500 mass %.

3. A magnetic disk, wherein an electroless Ni—P plating-treated layer and a magnetic substance layer thereon are provided on a surface of an aluminum alloy substrate comprising the aluminum alloy sheet according to claim 1 .

4. A method for producing the aluminum alloy sheet according to claim 1 , the method comprising:
a continuous casting step of continuously casting a cast plate using the aluminum alloy, and
a cold rolling step of cold-rolling the cast plate, wherein
in the casting step, the flow rate of molten metal flowing in a gutter for supplying a casting section for casting a casting plate is set to 100 kg/minute or lower, and also, a molten metal surface height is set to 30 mm or less and the casting speed is set to 0.4 to 1.5 m/minute.

5. The method according to claim 4 , further comprising:
a homogenization treatment step of heating the cast plate at 300 to 450° C. for 0.5 to 24 hours, between the continuous casting step and the cold rolling step.

6. The method according to claim 4 , further comprising:
an annealing treatment step of annealing the cast plate or cold-rolled sheet before or in the middle of the cold rolling.

Assignees

• Uacj Corp
• Furukawa Electric Co Ltd

Inventors

• Kitawaki Kotaro
• Yonemitsu Makoto
• Hatakeyama Hideyuki
• Toda Sadayuki
• Sakamoto Ryo
• Fujii Yasuo

Classifications

• C22F1/04

  of aluminium or alloys based thereon · CPC title

• C22C21/00

  Alloys based on aluminium · CPC title

• C22F1/00

  Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24) · CPC title

• G11B5/73919 Primary

  Aluminium or titanium elemental or alloy substrates · CPC title

• G11B5/8404

  manufacturing base layers · CPC title