Sliding wear behaviour of Zinc–Nickel alloy electrodeposits

The sliding wear behaviour of zinc–nickel electrodeposited coatings on mild steel substrates was investigated using a spherical pin-on-disc apparatus. The pin materials were alumina and hardened steel. The composition of the coatings was the following: 86 wt% zinc–14 wt% nickel. The friction coefficient of zinc–nickel coating against alumina counter spheres was found to be higher than that against hardened steel counter spheres. The weight loss of zinc–nickel coating after sliding against hardened steel counter spheres was found to be lower than that against alumina counter spheres. The main wear mechanism of the zinc–nickel coating sliding against stainless steel was noted to be severe shearing of the surface layers of the coating due to the ploughing action of the steel pins. For the wear experiments of zinc–nickel coatings against alumina spheres, a surface delamination mechanism is proposed to be the predominant wear mechanism of the coatings.