Wear Resistance of Electroplated Nickel-Hardened Gold

Wear resistance and hardness of nickel-hardened gold electroplated at current densities between 1 and 16 A/dm²and containing between 0.2 and 2.5 wt% nickel have been studied. In the current density range 1-4 A/dm²the wear changed from severe to mild and then to brittle upon increasing the nickel content in the deposit. In the range 4-16 A/ dm²the wear changed from severe to "adhesive brittle" and then to mild when increasing the nickel content. "Adhesive brittle" wear is characterized by a low coefficient of friction and a high wear rate. The dependence of wear behavior on current density can be explained by an inczease in internal stress with increasing current density. Regardless of current density the hardness increased with increasing nickel content.