High temperature friction and wear behaviour of Ni–P–Ag–Al2O3 hybrid nanocomposite coating

Abstract

Codeposition of silver and alumina particles has been performed within an Ni–P coating on carbon steel samples by electroless deposition to form an Ni–P–Ag–Al₂O₃ hybrid nanocomposite coating. The structure of heat treated coatings was evaluated by XRD analysis. Tribological properties of the coatings were investigated by a pin-on-disc test method using a 52100 steel pin as counter body at high temperature. A 3D optical profiler was employed to measure the wear rate of the deposits. Surface morphology, cross section and wear scars of the coatings were studied by using SEM equipped with EDS analysis. The results showed that tribological properties of Ni–P–Ag–Al₂O₃ hybrid coating are similar to Ni–P–Ag conventional composite coating. Moreover, friction coefficient and wear resistance of the hybrid coating are strongly influenced by self-lubricating silver thin layers formed between mating surfaces during high temperature sliding wear.