| 摘要 |
PURPOSE:To decrease defects such as surface depressions and projections of a cured nonmagnetic layer by using an alloy contg. nickel to form the cured nonmagnetic layer to be provided between a substrate and magnetic medium layer. CONSTITUTION:The cured nonmagnetic layer 21, the magnetic recording medium layer 3 and a lubricating layer 4 are successively laminated on the nonmagnetic substrate 1. The layer 21 is formed of an alloy contg. nickel, more preferably a ternary alloy of nickel, copper and phosphorus. The cracking of the layer 3 by a heat treatment during the formation of said layer is prevented if the content of the nickel in the ternary alloy is specified to <=60wt% and the content of the copper therein to 34+ or -5%. Since the layer 21 having substantial hardness and decreased surface defects is obtd. according to the above-mentioned constitution, the surface defects of the magnetic disk are decreased.
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