Structural design of Cr/GLC films for high tribological performance in artificial seawater: Cr/GLC ratio and multilayer structure

In this paper, graphite-like carbon (GLC) films with Cr buffer layer were fabricated by DC magnetron sputtering technique with the thickness ratio of Cr to GLC films varying from 1:2 to 1:20. The effect of Cr/GLC modulation ratio on microstructure, mechanical and tribological properties in artificial seawater was mainly investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), nano-indenter and a reciprocating sliding tribo-meter. The propagation of defects plays an important role in the evolution of delamination, which is critical to wear failure of GLC films in artificial seawater. Designing the proper multilayer structure could inhibit the defects propagation and thus protect the basis material. The multilayer Cr/GLC film with optimized ratio of 1:3 demonstrates a low average friction coefficient of 0.08 ± 0.006 and wear rate of (2.3 ± 0.3) × 10−8 mm3/(N m) in artificial seawater, respectively.