Electrical Contact Phenomena of Nickel Electrodeposits with Sharp Micro-Asperities

Nickel has not been considered as a contact material because it can be easily oxidized and the nickel oxide layer is insulating. We have previously developed a neutral pH ammoniacal bath that produces nickel phosphorus (Ni/P) alloy deposits (1 atomic % (a/o)P) with a unique surface morphology. These deposits maintain low contact resistance (R sub c) after several accelerated environmental tests. In the present study, the objective is to determine which particular surface features contribute to low R sub c values, especially after the coating is exposed to accelerated humidity testing.