Sliding wear behavior of electrodeposited Ni-W alloy and hard chrome coatings

Present study deals with the comparative sliding wear behavior of electrodeposited nickel-tungsten (Ni-W) alloy and conventional hard chrome (HCr) coatings. Ni-W alloys with different W (7.4, 10.5 and 11 at%) content in Ni were systematically deposited using pulsed electrodeposition from citrate bath. In addition, pure Ni coatings were also obtained from Watt׳s bath for comparison purpose. The dry sliding wear behavior of Ni, Ni-W and HCr coatings was compared using pin on disc configuration against WC-Co disc at three different loads. The results indicate that the wear rate is lowest for NiW10.5 amongst all the coatings despite of the fact that HCr coating is 12% harder than NiW10.5 coating. The wear behavior was attributed to ductile wear mechanism in NiW10.5 coatings as opposed to brittle fracture in the case of HCr coatings.