Impact-sliding wear properties of PVD CrN and WC/C coatings

This study focuses on the impact-sliding wear behaviour of CrN and WC/C tool protection coatings against Si3N4 ceramic material using a self-developed impact-sliding device. The wear mechanisms and tribochemical behaviour of the CrN coating and WC/C coating were compared and analysed using an optical microscope, 3D optical microscope, scanning electron microscope, energy-dispersive X-ray spectroscopy, electron probe microanalyzer, and X-ray photoelectron spectroscopy. The results showed that the WC/C coating exhibited very slight and uniform wear damage under impact-sliding conditions and the wear performance was much better than that of the CrN coating. Especially in the impact zone, the CrN coating showed peeling damage that greatly reduced the wear resistance to impact-sliding. The impact-sliding damage mechanisms of the CrN coating consisted of micro-peeling and plastic deformation, whereas those of the WC/C coating included deformation coordination and slight plastic deformation. The wear mechanisms of the CrN and WC/C coatings for the impact-sliding condition were fatigue wear, abrasive wear, and oxidation wear.