Control of magnetic film grain structure by modifying Ni-P plating of the substrate

摘要

High areal density magnetic recording media exhibiting low noise are formed with a Ni-P-X plating layer, in which X is an additive meeting the following requirement: (1) The additive has a higher oxidation potential than that of Ni so that grains of an additive-rich-oxide will form first during oxidation under a controlled atmosphere and grains of a Ni-rich-oxide, if any, will form subsequently and separately from the grains of the additive-rich oxide. (2) The additive has a tendency to segregate to the top surface. (3) The additive is not a catalyst poison for Ni-P plating in the composition range.