Exploring the potential for simultaneous enhancement of mechanical, wear and corrosion performance of the CrB2 protective film actuated by soluting Si

The moving parts in marine equipment have to face the high humidity and high salinity, improving the stability and durability in such harsh conditions is necessary. Developing the thin films with high hardness, wear resistance and corrosion resistance to protect the moving parts is an effective method. In this work, we introduce Si contents ranging from 0 to 14.5 at% in binary CrB2 film to enhance their comprehensive properties, and two structure Si contained sample with the CrSiB solid solution (3.5 at. %, 6.1 at. % and 7.3 at. % Si) and the CrSiB/Si nanocomposite (10.1 at. % and 14.5 at. % Si) are obtained. In comparison to the binary CrB2 and CrSiB/Si nanocomposite, the CrSiB solid solution film with 6.1 at. % Si exhibits the highest hardness of 23.23 ± 0.26 GPa, owing to the solid solution strengthening and grain boundary strengthening effects. Additionally, the CrSiB solid solution film with 6.1 at. % Si also exhibits the lowest wear rate with 5.18 × 10−8 mm3/Nm due to the highest H3/E2 value of 0.178. Moreover, the CrSiB solid solution film has the best corrosion resistance, this is because the thickest passivation layer with the minimal vacancy defects and the high-quality crystal structure of the film, which could effectively prevent Cl− from reaching the substrate through the film. This study highlights a promising structure for the protective thin film with comprehensive properties that meet stringent application conditions.