| 摘要 |
PURPOSE:To form a recording medium suitable for vertical recording by an electroless plating method provides superior mass-producibility, by forming a specific Co-alloy plated layer on a metallic substrate with an Ni-alloy plated layer, and then providing a protective film on it. CONSTITUTION:On a metallic substrate, a Co-alloy plated layer whose easy magnetization axis is oriented mainly at right angles to the film surface is formed with an Ni-alloy plated layer interposed, and on it, a protective film is formed. For example, on an Al alloy plate whose surface is flattened and smoothed, an Ni-P plated film having 30mum film thickness is formed by using an electroless plating liquid, and both the surfaces are finished into specular surfaces. After a Co-Mn-P alloy film (having about 1mum film thickness) is formed on the surface of the substrate with prescribed plating bath composition and under plating conditions, an alcohol solution of tetrahydroxycyanogen is applied over rotation and then baked to be set, thus forming a protective film consisting essentially of a silicate polymer which has 0.1mum film thickness. |
