Self-lubricating carbon nanotube reinforced nickel matrix composites

Nickel (Ni)-multiwalled carbon nanotube (CNT) composites have been processed in a monolithic form using the laser-engineered net shape (LENS (TM)) processing technique. Auger electron spectroscopy maps determined that the nanotubes were well dispersed and bonded in the nickel matrix and no interfacial chemical reaction products were determined in the as-synthesized composites. Mechanisms of solid lubrication have been investigated by micro-Raman spectroscopy spatial mapping of the worn surfaces to determine the formation of tribochemical products. The Ni-CNT composites exhibit a self-lubricating behavior, forming an in situ, low interfacial shear strength graphitic film during sliding, resulting in a decrease in friction coefficient compared to pure Ni.