Tribo-pair dependence of friction and wear moisture sensitivity for a-C:Si:Al carbon-based coating

► The a-C:Si:Al coating presented amorphous microstructure and good mechanical properties. ► Compacted carbonaceous tribo-film was formed in low relative humidity conditions. ► Colloidal silica tribo-film was formed in high relative humidity conditions. ► The a-C:Si:Al/SiO2 pair provided lowest tribological moisture sensitivity.