APPLICATION OF ELECTROLYTE JET TO AL2O3 P ARTICLE NI COMPOSITE ELECTRO-PLATING/

Electro-plating of an alumina particle/nickel composite system was car ried out on an aluminum alloy substrate, in which an electrolyte jet w as applied to improve the deposition rate and also to realize a requir ed volume fraction of alumina particles. The turbulent jet increases r emarkably the limiting current density which is the maximum value requ ired to obtain a qualified deposit. The limiting current density incre ases as the jet velocity increases, regardless of the alumina concentr ation in the electrolyte and its average diameter. It is saturated wit h approximately 120 x 10(2) A/m(2) at a jet velocity of 4 m/s and beco mes 15 times larger than that in conventional plating without a turbul ent jet. Alumina particles are then dispersed uniformly in the deposit . The volume fraction of the particle increases up to 30 vol% as the a lumina concentration in the electrolyte increases. The volume fraction decreases as the jet velocity increases. It shows a maximum value at a particle diameter of 1.7 mu m among the particles 2.8, 1.7 and 0.6 m u m in diameter. The resultant deposition rate of alumina particle/nic kel composite plating with the electrolyte jet is approximately 15 tim es faster than that of conventional electro-plating.