LAUSR

Abstract High-pressure common rail injection systems lubricated with low-lubricity fuel may be made more resistant to wear and scuffing with robust coatings. In this study, coatings of WC-Co were deposited onto heat-treated SAE 52100 steel substrates using thermal spray. The coated substrates were then treated using an ultrasonic nanocrystal surface modification (UNSM). Wear performance of the coatings was evaluated by ball-on-disk tribometer lubricated with three different fuels against three materials. Besides, the changes in surface roughness, hardness, microstructural evolution and critical load resulting from UNSM were systematically investigated. The UNSM controlled the surface roughness and hardness due to the grain size refinement, surface integrity and pore reduction. The application of UNSM exhibited higher wear resistance than the untreated coating. Wear mechanisms were investigated based on the results of surface characterizations, where the abrasion and oxidative wear modes took place.