MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To improve film strength and corrosion resistance by coating a thin magnetic film by a composite thin protective film consisting of the laminated layers of a trisilicon tetranitride film and carbon film with the silicon nitride film positioned on the thin magnetic film side. CONSTITUTION:An Ni-P plating film 2 having about 20mum thickness is formed to an Al substrate 1 and the film 2 is subjected to surface polishing to a specular surface having <=0.05mum average surface roughness. A Cr film 3 is formed on the film 2 to 0.25mum thickness and a Cu-Ni magnetic film 4 is formed to 0.05mum thickness by a sputtering method. The substrate is then placed to face a target consisting of sintered Si3N4 and an Si3N4 film 5 is formed by a high-frequency sputtering method in an inert gas on the Co-Ni film. A carbon film 6 having 0.02mum thickness is further formed thereon by by using the same sputtering device. The lubricating layer which has the film strength and corrosion resistance higher than the film strength and corrosion resistance of the conventional SiO2 film and is highly resistant to impact and wear is thus obtd. with the thin film thickness.