Tribological properties of CrN coating deposited on 20CrMo against tin bronze

摘要

A CrN coating was deposited on the piston pin material 20CrMo. The tribological properties of 20CrMo and CrN coating against tin bronze QSn7-0.2 were compared by pin-on-disk tests under dry friction and oil lubrication, respectively. The cross-sectional morphologies and structures of the coating were characterized through scanning electron microscopy and X-ray diffraction. The hardness, elastic modulus, and adhesion strength of the coating were tested through nano-hardness and scratch tests. The wear tracks were tested with an optical profilometer, and wear volume was calculated. Under dry friction conditions, the CrN coating exhibited a significantly stable friction coefficient and a relatively lower wear rate against QSn7-0.2 at various temperatures compared with 20CrMo. The wear rate decreased by 98.5% at 700°C. Under poly-alpha-olefine lubrication, the CrN coating reduced the load effect on the friction coefficient. Under engine oil 5 W40 lubrication, the CrN coating improved the tribological properties under high speed and heavy load conditions. Simultaneously, the CrN coating changed the friction and heat flow with increasing temperature.