Investigation of sputtered WCN coating for diesel engine pistons applications

WCN coating was deposited on the surface of ZS1115 piston by PVD method. The phases, microstructure, hardness and wear indexes were analyzed by XRD, XPS, HRTEM, SEM, nano-indentation CSM and Bruker profilometer to investigate the properties of WCN-coated pistons. It is found that the hardness of piston was increased from 1.2 to 33.3 GPa by coating WCN. The total wear volume of uncoated piston is 9153.0 mm3 and that of WCN-coated piston is 113.0 mm3. The wear resistance of the piston is improved by coating WCN on the surface due to the higher hardness and the existence of C and CNx lubricating phases and this could prolong its service life.