PURPOSE: To obtain the excellent wear resistance and lubricity of the surface of a magnetic recording medium having a magnetic film on a nonmagnetic substrate by forming an amorphous boron nitride film on the film surface of the magnetic film.
CONSTITUTION: A magnetic disk S on which the thin magnetic metallic film is formed is imposed on a supporting base 2 in a sputtering chamber 1 and a planar molding consisting of boron nitride is attached as a target 4 to a high-frequency power supply 3 to form the amorphous boron nitride film on the surface of the disk S. The amorphous boron nitride which is the protective film of said magnetic film is extremely hard and since crystal grain boundaries do not exist in said film, there are no problems such as erosion and exfoliation originating from the grain boundaries and the high-strength and robust characteristics are possessed; in addition, the exfoliation is obviated. The good homogeneity is provided over the wide area of the film and the excellent lubricity is obtd. by the inter-atom slip function possessed by the crystalline boron nitride.
SAKAI CHIAKI
IMOMOTO MASAHIRO
SEKI HIROSHI
