| 摘要 |
PROBLEM TO BE SOLVED: To enable excellent smoothness and high impact resistance by specifying the surface roughness of a nonmagnetic substrate, the surface roughness of a resin layer and the film thickness of the resin layer to specific values. SOLUTION: The surface roughness of the nonmagnetic substrate is specified to Ra=1 to 10 nm, Rmax<=50 nm, the surface roughness of the resin layer to Ra<=1 nm and the film thickness of the resin layer to <=1000 nm. An Al alloy, such as an Al-Mg alloy essentially consisting of Al is used for the nonmagnetic substrate. A polyimide resin and epoxy acrylate resin are desirable in terms of heat resistance and hardness as the resin layer. The resin layer is formed by applying a resin on the nonmagnetic substrate, then drying the coating by heating at need. A ground surface layer, such as a seed layer essentially consisting of, for example, Cr, is successively formed on the resin layer and thereafter, a Co alloy magnetic layer is formed. Further, a second ground surface layer essentially consisting of Cr is disposed between the ground surface layer and the Co alloy magnetic layer and an arbitrary protective layer consisting of carbon, carbon hydride, carbon nitride, etc., is formed on the magnetic layer and thereafter, a lubricating layer consisting of a fluorine lubricant is formed. |
