A new quaternary Ti–20Nb–10Zr–5Ta alloy with β-near microstructure was obtained. Its native passive film composition and its modification and corrosion resistance after 2000 immersion hours in simulated biofluids were studied. The native film on the alloy surface contains TiO2, Nb2O5, ZrO2, Ta2O5 protective oxides as was demonstrated by XPS. After 2000 h, XPS revealed the presence of same oxides and calcium, phosphorous ions deposited from physiological solutions as hydroxyapatite. In Ringer and Ringer–Brown solutions, the new alloy presented low corrosion rates. Impedance data exhibited a passive film with two layers: an inner, barrier layer and an outer, porous layer.
