Single-step electromechanical mechanical polishing on ni-p plated discs

Abstract

Beginning with a smooth ground aluminum blank with a relatively thin layer of leveled Ni—P, circumferential electropolishing/texturing is carried out to achieve a smooth oriented surface. A conductive slurry is provided between the disc and a porous texturing tape which is in contact with a conducting plate or equivalent conductor. The disc serves as the anode, and the conducting plate as the cathode, while the slurry, being conductive, functions as an electrolyte. In the presence of current, a reverse electroplating occurs so that the Ni—P dissolves to form Ni, or nickel ions which are carried away by the conductive slurry. The conductive slurry further supports or carries therein abrasive material so that by moving the porous texturing tape past the disc surface, the texturing tape picks up the abrasive material in the slurry and simultaneously with the reverse electroplating, provides the desired mechanical abrasion to achieve texturing of the disc surface. The abrasive material comprises diamond particles. The circumferential electropolishing/texturing polish is achieved by spinning the disc while applying the mechanical-chemical action through the slurry system to the disc surface with electric current passing through the electrically conducting interface during processing.