The stability of oxide films potentiodynamically (50mVs −1 ) grown up to 8.0V(SCE) on Ti–50Zr at.% in H 2 SO 4 , HNO 3 , CH 3 SO 3 H, and H 3 PO 4 (pH≈1) was assessed in the growth electrolyte itself or in a Ringer solution. For all anodizing electrolytes, oxide films become stabler as their thickness increases. In the Ringer solution, the oxide film stability is affected by the anodizing electrolyte; for oxides grown up to 8.0V(SCE), films obtained in H 3 PO 4 are slightly less stable than the ones obtained in the other acids, whereas films obtained in H 2 SO 4 are clearly the stablest ones.