Wear behavior and atomic competition mechanism of flexible wear-resistant coating with oxygen-free zone in Ti6Al4V alloy

The flexible wear-resistant coating on Ti6Al4V substrate was successfully fabricated by plasma powder cladding with Al–Si powder. The microstructure, element distribution and phase component of the flexible wear-resistant coating were characterized by the field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and the X-ray diffractometer (XRD). The micro-hardness of coating was measured by micro-hardness tester. The wear-resistance of Al–Si coating was evaluated by sliding friction experiment. The prepared coatings have no cracks and a good metallurgical bonding (MB) with the substrate. The wear-resistance of the coating surface is about twice as much as that of Ti6Al4V substrate. Furthermore, the in-between MB zone has the more excellent wear-resistance (about 7 times). The oxygen free zone can be formed in the MB zone, providing a good toughness for the flexible wear-resistant coating. The wear mode is adhesive wear for the flexible wear-resistant Al–Si coatings. Based on the self-consistent bond length difference (SCBLD) method, the competition among atoms in MB zone as well as the formation mechanism of flexible oxygen free zone is investigated.