The Oxidation of Electroplated and Sputter Deposited Nickel- Phosphorus Alloys.

Nickel-phosphorus alloys, Ni/P are being investigated in several laboratories because of their corrosion resistance. We have studied the oxidation of a series of Ni/P sub x films at 80C and 85% RH. Auger electron spectroscopy shows that little P is present on the surface or in the oxide layer after oxidation, and that the small amount of P present in the oxide is not present as phosphate or phosphite. These results are inconsistent with the formation of a ternary Ni-P-O glass or passivating phosphate or hypophosphite layers reported elsewhere. However the presence of P in the original alloy appears to be important. Increasing the P concentration form 7 to 18 at% decreases the thickness of the oxide layer. For the same oxidation conditions, the thickness and composition of the oxide layer is the same on both electrodeposited (polycrystalline) and sputter deposited (amorphous) Ni/P sub x .