| 摘要 |
PROBLEM TO BE SOLVED: To obtain a hard disk substrate capable of obtaining a smooth plating film surface by electroless NiP plating without deteriorating acid corrosion resistance.SOLUTION: There is provided a method for producing a hard disk substrate having an electroless NiP plating film, in which a substrate is immersed in a first electroless NiP plating bath containing an additive having a smoothing effect to form a lower layer of the electroless NiP plating film having an average surface roughness smaller than an average surface roughness of the surface on the surface of the substrate. Further, the substrate on which the lower layer of the electroless NiP plating film is formed is immersed in a second electroless NiP plating bath to form an upper layer of an electroless NiP plating film having acid corrosion resistance and a plating film thickness of 4 μm or more. |
