Investigation of Friction and Wear Properties of Electroless Ni–P–Cu Coating Under Dry Condition

Abstract

This study presents the deposition and tribological characterization of electroless Ni–P–Cu coatings deposited on AISI 1040 steel specimens. After deposition, coatings are heat treated at 500[Formula: see text]C for 1[Formula: see text]h. Surface morphology study of the coatings reveals its typical cauliflower like appearance. Composition study of the coatings using energy dispersive X-ray analysis indicates that the deposit lies in the high phosphorus range. The coatings undergo crystallization on heat treatment. A significant improvement in microhardness of the coatings is also observed on heat treatment due to the precipitation of hard crystalline phases. The heat-treated coatings are subjected to sliding wear tests on a pin-on-disc type tribo-tester under dry condition by varying the applied normal load, sliding speed and sliding duration. The coefficient of friction (COF) increases with an increase in the applied normal load while it decreases with an increase in the sliding speed. The wear depth on the other hand increases with an increase in applied normal load as well as sliding speed. The worn surface morphology mainly indicates fracture of the nodules.