The effects of the ambient humidity on the friction and wear properties of Ni-W-P alloy platings with various phosphorus contents were examined by horizontal reciprocating friction and wear tests and XPS. To clarify the role of phosphorus in the friction and wear behavior of alloy plating, the same experiments were carried out to for electroless Ni-P, Ni-W alloy and Cr platings.
The friction and wear properties of Ni-W-P alloy plating were affected greatly by the ambient humidity depending on the phosphorus content. Both the friction coefficient and the wear amount of the alloy plating have decreased with increase in the ambient humidity and also the phosphorus content of the alloy plating. By XPS measurements, a phosphorus oxide layer was found to be formed on the sliding surfaces in moist atmospheres, and to contribute to low friction and the wear characteristics of the Ni-W-P alloy plating.
