| 摘要 |
A provision of a magnetic disk substrate using, as a plated substrate, glass with high hardness in place of aluminum. The magnetic disk substrate is small-sized, can stand against an impact when it is carried, and avoids leaving struck damages (head snap) even if it is used for recent note- or mobile-type computers having a head which is located as closely as possible to the substrate. The magnetic disk substrate comprises forming a nickel/phosphorus coating with a film thickness of 8 mum-20 mum or less on crystallized glass with a roughness Ra of 0.05 to 0.5 mum, the roughness being measured by a tracer and contact type roughness meter after the glass is ground (lapped) and polishing the nickel/phosphorus coating to a depth of 3 mum or more in a polishing process with the thickness of the plating film left unremoved being 5 mum or more.
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