PRETREATMENT OF ELECTROLESS NIP PLATING

摘要

PURPOSE:To smooth and uniform a Zn substn. layer to be formed on an Al substrate for a magnetic disk by subjecting the substrate to a zincate treatment while impressing ultrasonic waves thereto. CONSTITUTION:The Al substrate for the magnetic disk is degreased, etched and washed and is then subjected to the zincate treatment after the ultrasonic waves are irradiated thereto. The substrate is preferably uniformly oscillated by disposing an ultrasonic oscillator in the direction parallel with the substrate in the stage of the treatment. The zincate treatment may be repeated plural times. The treated substrate is put into an electroless plating cell to form an NiP plating film thereon. Since the smooth and uniform Zn layer is formed on the substrate according to the above-mentioned method, the substrate consisting of the NiP plating film having high smoothness is formed.