Preparation and tribological properties of Cu/Ni-P multilayer electrodeposited on beryllium bronze

Cu/Ni-P multilayer was electrodeposited on beryllium bronze substrate by bi-pulse plating. The friction and wear behavior of the resulting multilayer sliding against AISI-52100 steel ball was investigated on a unidirectional friction and wear tester in a ball-on-disc configuration. The morphology and wear mechanisms of the multilayer were analyzed based on atomic force microscopic and scanning electron microscopic analyses of the original and worn surfaces of the multilayer. As the results, the Cu/Ni-P multilayer was compact and smooth and showed high hardness and good antiwear and friction-reducing behavior at smaller load and sliding speed. The increased wear-resistance of the Cu/Ni-P multilayer was related to the decreasing of the grain size in the presence of P, which contributed to retard the generation and growth of the Ni nuclei along the (111) plane and hence to increase the hardness and wear-resistance of the multilayer. The increased wear-resistance of the Cu/Ni-P multilayer was also dependent on its transfer onto the worn surface of the counterpart AISI-52100 steel to some extent. The Cu/Ni-P multilayer sliding against the steel at smaller load and sliding speed was characterized by slight scuffing and adhesion, while it experienced severe adhesion and plastic deformation as slid against the steel counterpart at a larger load.