Aluminum alloy substrate for magnetic disk, method for producing the same, and magnetic disk using aluminum alloy substrate for magnetic disk

Patent metadata

Field	Value
Publication number	US-11423937-B2
Application number	US-201816644612-A
Country	US
Kind code	B2
Filing date	May 15, 2018
Priority date	Sep 28, 2017
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, “%”) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an Al—Fe-based intermetallic compound having a longest diameter of 2 μm or more and less than 3 μm is dispersed at a distribution density of 1000 particles/mm2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 μm or more is dispersed at a distribution density of 1 particle/mm2 or less; a method for producing the same; and a magnetic disk in which an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

First claim

The invention claimed is:

1. An aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate comprising an aluminum alloy comprising 0.4 to 3.0 mass % of Fe, less than 0.10 mass % of Si, less than 0.10 mass % of Mg, and a balance of Al and unavoidable impurities,
wherein an Al—Fe-based intermetallic compound having a longest diameter of 2 μm or more and less than 3 μm is dispersed at a distribution density of 1000 particles/mm 2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 μm or more is dispersed at a distribution density of 1 particle/mm 2 or less.

2. The aluminum alloy substrate for a magnetic disk according to claim 1 ,
wherein the aluminum alloy further comprises one or more selected from a group consisting of 0.1 to 3.0 mass % of Mn, 0.1 to 3.0 mass % of Ni, 0.005 to 1.000 mass % of Cu, 0.01 to 1.00 mass % of Cr, and 0.01 to 1.00 mass % of Zr.

3. The aluminum alloy substrate for a magnetic disk according to claim 1 ,
wherein the aluminum alloy further comprises 0.005 to 1.000 mass % of Zn.

4. The aluminum alloy substrate for a magnetic disk according to claim 1 ,
wherein the aluminum alloy further comprises one or more selected from a group consisting of Ti, B, and V in a total content of 0.005 to 0.500 mass % or less.

5. The aluminum alloy substrate for a magnetic disk according to claim 1 ,
wherein a flatness is 30 μm or less.

6. The aluminum alloy substrate for a magnetic disk according to claim 1 ,
wherein a tensile strength is 90 MPa or more.

7. A magnetic disk wherein an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk according to claim 1 .

8. The aluminum alloy substrate for a magnetic disk according to claim 2 ,
wherein the aluminum alloy further comprises 0.005 to 1.000 mass % of Zn.

9. The aluminum alloy substrate for a magnetic disk according to claim 2 ,
wherein the aluminum alloy further comprises one or more selected from a group consisting of Ti, B, and V in a total content of 0.005 to 0.500 mass % or less.

10. The aluminum alloy substrate for a magnetic disk according to claim 3 ,
wherein the aluminum alloy further comprises one or more selected from a group consisting of Ti, B, and V in a total content of 0.005 to 0.500 mass % or less.

11. The aluminum alloy substrate for a magnetic disk according to claim 8 ,
wherein the aluminum alloy further comprises one or more selected from a group consisting of Ti, B, and V in a total content of 0.005 to 0.500 mass % or less.

12. A method for producing an aluminum alloy substrate for a magnetic disk according to claim 1 , the method comprising:
a casting step of casting an ingot by using the aluminum alloy;
a hot-rolling step of hot-rolling the ingot;
a cold-rolling step of cold-rolling a hot-rolled sheet;
a disk blank stamping step of stamping the cold-rolled sheet to have an annular shape;
a pressurization annealing step of subjecting a stamped disk blank to pressurization annealing; and
a cutting and grinding step of subjecting the disk blank subjected to the pressurization annealing, to cutting work and grinding work,
wherein the ingot is hot-rolled at a rolling reduction of 40% or more in a temperature range of 250 to 450° C. in the hot-rolling step.

13. The method for producing an aluminum alloy substrate for a magnetic disk according to claim 12 , the method further comprising a homogenization heat treatment step of heat-treating the ingot at 280 to 620° C. for 0.5 to 60 hours between the casting step and the hot-rolling step.

14. The method for producing an aluminum alloy substrate for a magnetic disk according to claim 12 , the method further comprising an annealing treatment step of annealing the rolled sheet, the annealing treatment step being a batch annealing treatment step performed at 300 to 390° C. for 0.1 to 10 hours or a continuous annealing treatment step performed at 400 to 500° C. for 0 to 60 seconds, before or in the cold-rolling step.

Assignees

• Uacj Corp
• Furukawa Electric Co Ltd

Inventors

• Kitawaki Kotaro
• Hatakeyama Hideyuki
• Nakayama Takashi
• Fujii Yasuo
• Kumagai Wataru

Classifications

• G11B5/82

  Disk carriers · CPC title

• C22F1/04

  of aluminium or alloys based thereon · CPC title

• G11B5/73919

  Aluminium or titanium elemental or alloy substrates · CPC title

• G11B5/70615

  containing Fe metal or alloys (G11B5/70621 takes precedence) · CPC title

• G11B5/73913 Primary

  Composites or coated substrates · CPC title