| 摘要 |
PURPOSE:To obtain a recording medium having mechanical strength without deteriorating the recording and reproducing characteristics by smoothening the surface of a nonmagnetic Ni-P film, depositing a magnetic body for vertical magnetic recording contg. Co-Cr as the principal component, and carrying out heat treatment. CONSTITUTION:The surface of an Al substrate 1 is pretreated and cleaned by a known method, and a thick Ni-P layer 2 having several 10mum thickness is deposited by electroless plating. The surface of the layer 2 is finished to small surface roughness by mechanical working, and heat treatment is carried out at 250-300 deg.C for about several 10min-1hr in an electric furnace or the like. The Vickers hardness Hv of the Ni-P film 2 having about 50mum thickness is increased from about 300 to about 900 by the heat treatment. A vertically magnetizable film 3 of Co-20wt%Cr or the like having about 1mum thickness is then deposited on the film 2 by RF sputtering or other method. |
