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AssigneeKabushiki Kaisha Kobe Seiko Sho
InventorsTomoyuki Sugita, Yuichi Hayashi, Keiji Okada, Hideo Fujimoto
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A blank for magnetic hard disk and a method for producing the same are provided, characterized in that the attachment or adhesion of a blank of a disk shape to each other can be prevented when such blank is stacked together for disk annealing, thereby improving the productivity of magnetic hard disk, and that the damage of blank surface can be prevented during blanking. Firstly, an aluminium alloy plate is subjected to continuous surface washing process with an etching solution while winding off the aluminium alloy plate in a coil, whereby the oxide film on the surface of the aluminium alloy plate is removed to concurrently deposit insoluble smut on the surface. Then, the aluminium alloy plate after the washing process is pressed for blanking thereof into a blank of a disk shape.
An aluminum or aluminum based alloy blank for a magnetic hard disk with insoluble smut generated from chemical etching being deposited on a surface thereof, an aluminum oxide film having been substantially removed by chemical etching from said surface, and said smut generated from chemical etching being deposited on said surface from which an aluminum oxide film has been substantially removed, said blank having improved peelability as compared to when an aluminum oxide film is not removed.
Dependencies are inferred from the claim text.