Synergistic enhancement of wear resistance via CrN coating and layered double hydroxides systems

Abstract

The long-term operational reliability of mechanical equipment is significantly influenced by friction and wear. In this study, we developed a synergistic protection system by incorporating CrN coating and ZnAl layered double hydroxides (ZnAl LDH). The CrN coating was deposited using magnetron sputtering, and ZnAl LDH was synthesized via the hydrothermal method. To enhance the dispersion and tribological properties of ZnAl LDH in base oil, surface modification with stearic acid (SA) was performed through dehydration condensation bonding between the -OH groups on the ZnAl LDH surface and the -COOH groups on SA. Tribological tests were carried out to evaluate the lubrication properties of the two different LDHs when used as additives at varying concentrations in PAO-10 oil. The results demonstrate that adding 2.5 wt% SA-ZnAl LDH significantly improved the anti-wear performance of CrN-coated surfaces. This improvement is primarily attributed to the adsorption of LDH onto the CrN coating surface, which promote tribo-film formation. Overall, by benefiting from the synergistic effect between the LDH with superior lubricating properties and the CrN coating's excellent mechanical characteristics, a low-wear synergistic protection system was established, effectively protecting the steel substrate from severe wear.