Sliding wear studies of ni-cu composition-modulated coatings on steel

Abstract

Sliding wear measurements have been conducted on Ni-Cu composition-modulated coatings on steel. The electrodeposited coatings consisted of alternate layers of nickel and copper with equal layer spacings of either 10 or 100 nm. Pure nickel and pure copper coatings were also prepared in a similar manner and studied. The coated cylinders were slid against AISI type 52100 steel in a crossed cylinder geometry under clean conditions without lubrication at various loads and sliding distances. It was found that the most wearresistant coating was the composition-modulated alloy having the smallest layer spacing, 10 nm. This effect was most pronounced at low loads. Both composition-modulated coatings showed less wear than coatings of pure copper and nickel deposited from the same solution. The layer microstructure in these composition-modulated coatings may provide internal barriers to wear damage, thus leading to the increases in wear resistance. Results from examination of the worn specimens and collections of wear debris are also described.