Wear mechanism of Ni–P–BN(h) composite autocatalytic coatings

Sliding wear experiments at room temperature were performed, using a pin-on-disc configuration, in order to study the wear mechanism of autocatalytic composite Ni–P–BN(h) coatings deposited on AISI 316L stainless steel against AISI 52100 steel balls. Coatings with 11, 35, 45 and 67 vol.% BN(h) were obtained by dispersing the BN(h) of an average particle size of 5.16 μm in a sodium hypophosphite based autocatalytic bath with enhanced agitation and surfactant addition. Scanning Electron Microscopy and 3D perfilometry techniques were employed to study the wear scars. Knoop microhardness, roughness, friction coefficients and wear resistance of the coatings for all experimental conditions are also reported. The results obtained indicate that, in the case of coatings with BN(h) content higher than 11 vol.%, the wear mechanism is a mild adhesive wear mechanism (adhesive ploughing) with high plastic strain of the coatings and low coating transfer to the ball. Coatings with 11 vol.% BN(h) show a mixed mechanism of adhesive and abrasive wear.