The Furukawa Electric Co., Ltd.

Uacj Corporation

Wataru Kumagai

Kotaro Kitawaki

Ryo Sakamoto

Hideyuki Hatakeyama

Takashi Nakayama

Toshihiro Nakamura

Yasuo Fujii

Hideki Takahashi

Takuya Murata

Makoto Yonemitsu

Naoki Kitamura

Shinpei Todo

Ryohei Yamada

Kimie Imakawa

Yu Matsui

Keita Yoshimura

An aluminum alloy substrate for a magnetic disc is made of an aluminum alloy, containing Fe: 1.80 mass % or less, Mn: 0.70 mass % or less, Ni: 2.50 mass % or less, Si: 2.50 mass % or less, Cu: 1.00 mass % or less, Zn: 0.48 mass % or less and Mg: 1.00 to 3.50 mass %, wherein a total content of Fe, Mn and Ni is 1.60 to 4.50 mass % and a mass ratio of Cu/Zn is 0.01 to 0.35 or 6.00 to 50.00, with a balance being Al and inevitable impurities.

Aluminum alloy substrate for magnetic disc and magnetic disc

An aluminum alloy disc blank for a magnetic disc made of an aluminum alloy containing Fe: 0.005 to 1.800 mass % with the balance being Al and inevitable impurities, wherein a flatness change of the aluminum alloy disc blank for a magnetic disc when the aluminum alloy disc blank for a magnetic disc is held in the atmosphere at 50° C. or lower for 336 hours is 2.0 μm or less.

Aluminum alloy disc blank for magnetic disc and magnetic disc

An example thin substrate built-in hard disk drive includes a magnetic disk in a disk shape having a through-hole at the center, a spindle motor inserted into the through-hole of the magnetic disk and co-rotatably supporting the magnetic disk, and a base plate made of an aluminum alloy and supporting the spindle motor. The base plate has a metallographic structure in which a perimeter of a second phase particle having a longest diameter of 10 μm or more is 3 mm/mmor more, and the number of second phase particles having a longest diameter of 500 μm or more is 0 particles/mm.

Thin substrate built-in hard disk drive and base plate member for thin substrate built-in hard disk drive

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 % of Fe and the balance of Al and unavoidable impurities, in which second phase particles having a longest diameter of 0.5 &#x3bc;m or more and less than 2.0 &#x3bc;m are dispersed at a distribution density of 5000 particles/mmor more; a method for producing the same; and a magnetic disk using the aluminum alloy substrate for a magnetic disk.

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

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&#x2014;Fe-based intermetallic compound having a longest diameter of 2 &#x3bc;m or more and less than 3 &#x3bc;m is dispersed at a distribution density of 1000 particles/mmor more, and a Mg&#x2014;Si-based intermetallic compound having a longest diameter of 1 &#x3bc;m or more is dispersed at a distribution density of 1 particle/mmor less; a method for producing the same; and a magnetic disk in which an electroless Ni&#x2014;P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

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

An aluminum alloy substrate () for magnetic disk satisfies at least two of three inequalities of an inequality group [A] and satisfies all of four inequalities of an inequality group [B], or satisfies at least two of the three inequalities of the inequality group [A] and satisfies all of four inequalities of an inequality group [C], when a plate thickness of the disk at a position (b1) is defined as t, a plate thickness at a position (b2) is defined as t, a plate thickness at a position (b3) is defined as t, a plate thickness at a position (a1) is defined as t, a plate thickness at a position (a2) is defined as t, and a plate thickness at a position (a3) is defined as t.

Aluminum alloy substrate for magnetic disk, disk drive device, method for manufacturing aluminum alloy substrate for magnetic disk, and method for measuring aluminum alloy substrate for magnetic disk

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Tokyo, Japan

Wataru Kumagai