Continuously layer-by-layer assembled multilayer coating to achieve excellent tribological properties and electrical contact stability

Abstract

Balance between mechanical properties and electrical contact stability is one of the most important challenges in the field of electrical contact. In this study, multilayer coatings were designed based on alternating soft/hard layer strategy using magnetron sputtering technology. The main intention was to investigate the effect of the alternating structure of soft and hard layers on the mechanical, tribological properties and electrical contact behavior of multilayer coatings. The results demonstrated that as the number of heterogeneous interfaces in the multilayer coating increases, the hardness and yield strength raised to 5.1 GPa and 875 MPa, respectively, while the contact resistance was only 5.3 mΩ at a low contact force of 10 gf. The as-obtained multilayer coating maintained good structural integrity after 3000 wearing cycles at an ultra-high contact force of 8 N. The superior wear resistance is attributed to the high-density heterogeneous interfaces which served as a barrier to stress distribution, inhibiting the propagation of deformation carriers, shear bands and dislocations, thereby achieving an outstanding wear resistance. This finding provides a novel design strategy for developing high-quality coating.