Passive film formation on the new biocompatible non-equiatomicTi21Nb24Mo23Hf17Ta15 high entropy alloy before and after resting in simulated body fluid

• Published in: Corrosion science Vol. 207; p. 110607
• Main Authors: Roche, Virginie, Champion, Yannick, Bataev, Ivan A., Jorge Junior, Alberto Moreira
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2022
• Subjects: Corrosion properties; Electrochemical impedance spectroscopy; High entropy alloys; Implant storage simulation; In-body implant simulation; Passive film formation; High entropy alloys; Passive film formation; Implant storage simulation; In-body implant simulation; Corrosion properties; Electrochemical impedance spectroscopy
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2022.110607

The Ti21Nb24Mo23Hf17Ta15 biocompatible high entropy alloy (HEA) was analyzed for different air-exposure times before corrosion tests in simulated body fluid (SBF), simulating implant air storage before implantation, presenting tremendous surface passivation capacity. Electrochemical impedance spectroscopy indicates layers thickening during air exposure with a very capacitive behavior. Two-time constant relaxation confirmed the formation of a double layer and oxide one. The equivalent Relectrolite+ (Coxide)+ (R//CPE) circuit model simulated the EIS behavior. Atoxic inert oxides were observed by X-ray photoelectron spectroscopy before and after SBF immersion for seven days, not impairing biocompatibility and producing a stable passive film. •A new Ti21Nb24Mo23Hf17Ta15 biocompatible high entropy alloy (HEA) was prepared.•Implant air-storage and in-body in SBF were simulated.•The HEA presented a great capacity for surface passivation, very corrosion resistant.•Inert inner and porous outer layer forms the passive film, keeping biocompatibility.•A two time-constants model allowed fitting successfully the EIS results.