| 摘要 |
PROBLEM TO BE SOLVED: To decrease a residual corrosive compd. which causes surface defects, by forming a magnetic layer and a protective layer on a substrate and using a polyethylene terephthalate abrasive material containing each specified amt. of chlorine ion and sulfate ion to polish the protective layer. SOLUTION: A metal base layer such as chromium is preferably formed to 50 to 20000nm thickness on a nonmagnetic substrate comprising an aluminum alloy substrate by sputtering. Then a magnetic layer is formed thereon and a protective layer such as carbon is formed to preferably 100 to 600A thickness. After the protective layer is formed, an abrasive material having <=80μg/m<2> chlorine ion and <=40μg/m<2> sulfate ion, such as polyethylene terephthalate film is used for polishing. If chlorine ion and sulfate ion remains on the surface of the magnetic recording medium after polishing, these ions intrude through minute scratches produced by polishing and corrode the magnetic layer. By using this abrasive material, these problems can be avoided.
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