3 research outputs found
Corrosion behavior and bioactivity of equimolar high entropy alloy TiNbZrHfTa : growth of nanotubes oxides
No full textInternational audienceIn this work, we report for the first time the fabrication and study of the corrosion resistance and bioactivity performances of new biocompatible High Entropy Alloys (HEA) of two different equimolar compositions: TiNbMoHfTa and TiNbZrHfTa. Both alloys were fabricated by vacuum arc-melting. The TiNbMoHfTa alloy exhibits a high strength of ~1.3 GPa and a low Young's modulus of ~93 GPa. The TiNbZrHfTa alloy exhibits suitable mechanical properties with a tensile strength of 1050 MPa and Young's modulus of 66 GPa. Both of which are much higher and lower than several conventional implant alloys. Alloys corrosion behaviors were investigated in simulated body fluid (SBF) solution at 37°C in the dark. TiNbMoHfTa Samples were analyzed in several air-exposition times between polishing and corrosion measurements to simulate their storage before implantation. X-ray photoelectron spectroscopy (XPS) analyses of the air-exposed surfaces were compared. The passive layer's growth with the air exposition time was studied by Electrochemical impedance spectroscopy (EIS). After 24h in the air, the passive film's stability was achieved, indicating that the corrosion properties might be independent of the film thickness. XPS confirmed that the passive film contains chemical-stable oxides of the five alloy elements. Nanotubular architectures were grown on the surface of the TiNbZrHfTa alloy and characterized by SEM, EDX, XRD, and XPS. Corrosion resistance measurements were performed through polarization and electrochemical impedance studies. The obtained results proved that the surface-modified TiNbZrHfTa high entropy alloy could be an attractive candidate to replace conventional alloys
