Tribological behavior of Ni-based composite under distilled water lubrication

Ni–Ni3Si–graphite composite was fabricated by the reactive sintering of Ni, fine grain SiC and graphite. The wear behavior of the composite under dry-sliding and water-lubricated sliding against stainless steel was studied using pin-on-disk test. The friction coefficient and wear rate of the composite under water lubrication were one half and one fifteenth as much as those under dry-sliding, respectively. The friction coefficients under water lubrication exhibited small variations with the loads and speeds. The worn surface of the composite under water lubrication was characterized by mild scuffing and micro cracks as well as fine wear debris. The worn surface of the composite under dry-sliding was characterized by severe adhesion and oxidation, and large plate-like wear debris. The water accelerated the oxidation of the stainless steel and the formation of SiO2 from Ni3Si. The friction and wear of the composite under water lubrication was reduced.