Study of dry sliding wear of electrodeposited Zn-Ni alloy coatings

Dry sliding wear behaviour of electrodeposited zinc-nickel alloy coatings containing 7% and 14.4% Ni and pure zinc coating against gray cast iron counterbody was studied using a pin-on-disc type apparatus. Wear tests were carried out under three different loads viz.. 120. 175 and 250g for sliding distances ranging from 416 to 1248m. All the tests were performed in the ambient air al room temperature at a linear speed of 1.5 m/s. Extent of wear damage and wear mechanism were investigated by means of measurement of width of wear scar and metallography. Zn-Ni coating with 14.4% Ni was found to be more wear resistant than the coating with 7% Ni. Pure zinc coating was found to be the least resistant to wear. It was seen that adhesive wear was the main mechanism in case of pure zinc coating whereas abrasive wear is believed to be the dominant mechanism in both Zn-7% Ni and Zn-14.4% Ni coatings.