Evaluation of the Wear Resistance Behavior of Zn-Ni and Zn-Ni/Sio2 Composite Coatings

Abstract

The sliding wear resistance behavior of Zn-Ni and Zn-Ni/SiO 2 composite coatings were investigated using a sliding wear rig. Wear behavior was mainly evaluated based on weight loss measurements. Effect of applied load and no. of cycles on the weight loss of the coatings were given particular attention. Field Emission Gun Scanning Electron Microscopy (FEGSEM) was used to investigate the wear tracks to determine the prevalent wear mechanisms. It was found that weight loss of Zn-11%Ni/1%SiO 2 was lower than those of Zn-11%Ni and Zn-11%Ni/11%SiO 2 with a constant load of 10N and increasing number of cycles. Their weight loss took the following trend; Zn-11%Ni/1%SiO 2 <Zn-11%Ni<Zn-11%Ni/11%SiO 2. However, with increasing normal load, all three systems of coatings exhibited a mixed response at a constant cycle of 100. At a higher load, a reverse trend to that of a lower load was observed. At 10N the weight loss of Zn-11%Ni<Zn-11%Ni1%SiO 2 <Zn-11%Ni/11%SiO 2 while at 25N it took a reverse trend where weight loss of Zn-11%Ni/11%SiO 2 <Zn-11%1%SiO 2 <Zn-11%Ni. Morphology of the wear tracks revealed that the wear mechanism of Zn-Ni/SiO 2 coatings were mainly a function of particle content. Optimum wear resistance behavior was observed for coatings of Zn-Ni containing 1wt% SiO 2