Corrosion Science 240 (2024) 112418

 Corrosion and tribocorrosion performance degradation mechanism of multilayered graphite-like carbon (GLC) coatings under deep-sea immersion in the western Pacific
Yingrui Liu, Guanshui Ma, Xin Ma, Hao Li, Peng Guo, Aiying Wang, Peiling Ke

Graphite-like carbon (GLC) coating features significant sp2- hybridized carbon and a unique combination of favorable properties such as low friction coefficient, high hardness and chemical inertness. As a result, its environmental sensitivity is greatly reduced and suitable for aqueous lubrication environment application, such as the surface protective coatings on moving components in deep sea environments. Deep-sea hydrostatic pressure is the most important factor affecting the corrosion properties of materials. However, no research has been reported on the performance evolution of carbon-based solid lubricating coating materials in real deep-sea environments. For this reason, this study employed a long-term exposure experiment at varying depths (500 m, 1500 m and 5942 m) in Pacific Ocean lasting 342 days. By combining analysis of the corrosion resistance, corrosion morphologies and tribology properties after exposure, the impact laws and mechanisms of actual deep-sea environments on the corrosion and tribology properties of GLC coatings were investigated comprehensively. Results showed that the atomic structure of the top-layer GLC layer remained almost unchanged after immersion, but severe corrosion across multi-scaled interfaces was significantly stimulated as the immersion depth increased. This further led to the weakening of coating density and adhesion strength, with the wear rate and corrosion rate being two orders of magnitude larger than those of the as-deposited coating. Therefore, reducing defect density and conductivity is the key to designing GLC coatings for deep-sea applications.

URL：https://doi.org/10.1016/j.corsci.2024.112418