Process for preparing magnetic disk
OwnerNoboru Tsuya, Tadao Tokushima +1inventors
InventorsNoboru Tsuya, Tadao Tokushima, Toshiro Takahashi
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Abstract
This invention relates to a process for preparing a magnetic disk, which comprises (a) subjecting a substrate having an anodized aluminum film to mirror surface-finishing, (b) widening pores of the anodized aluminum film by chemical dissolution treatment so that the total area of pores becomes from 20 to 80% of the entire surface area, thereby retaining crystalline alumina of the anodized aluminum film extruded after the chemical dissolution treatment, and (c) coating the resultant substrate with a magnetic continuous thin film.
Claims1
A process for preparing a magnetic disk having a magnetic continuous thin film on a concavo-convex roughened surface of an anodized aluminum film, consisting essentially of
- (a) subjecting a substrate having an anodized aluminum film having a thickness of at least 4 .mu.m and a three-layered structure comprising crystalline alumina, amorphous alumina and amorphous alumina containing an acid or alkali ion to mirror surface finishing,
- (b) treating the anodized aluminum to chemical dissolution treatment thereby widening pores of the anodized aluminum film so that total area of pores become from 20 to 80% of the entire surface area, thereby retaining a alumina of the anodized aluminum film extruding after the chemical dissolution treatment, whereby a concavo-convex surface is formed on said anodized aluminum film,
- (c) coating the concavo-convex surface with a protective layer selected from the group consisting of C and Cr,
- (d) coating said concavo-convex surface with magnetic continuous thin film on said anodized aluminum film subjected to chemical dissolution treatment and protective layer coating,
- (e) packing the pores after the coating with lubricant, thereby retaining the depth of said pores from 50 to 500 .ANG..
Dependencies are inferred from the claim text.