Abstract:To improve the friction and wear performance at room and elevated temperatures, Ti48Al2Nb2Cr (at.%) alloy was anodically fluorinated in an NH₄F-containing electrolyte. The effects of anodic fluorination on the friction coefficient, wear rate, wear track morphology, and adhesion strength between the oxide scale and substrate were investigated. Results showed that the in-situ formation of Al₂O₃-enriched oxide scale was promoted due to fluorine effect, by which the surface hardness and wear resistance were both enhanced. After the friction and wear test, no noticeable changes were found on the fluorinated Ti48Al2Nb2Cr, whilst severe abrasion was evident on the GCr15 counterpart. This indicates that anodic fluorination could effectively enhance the friction and wear performance of Ti48Al2Nb2Cr alloy. At elevated temperatures, the dominant wear mechanism of the fluorinated Ti48Al2Nb2Cr/GCr15 pair was oxidation wear and adhesive wear.

Key words: TiAl alloy; anodic fluorination; fluorine effect; tribological property; wear resistance