Effect of electrolytic ZrO2 coatings on the breakdown potential of NiTi wires used as endovascular implants

We report on the effect of electrolytic ZrO2 coatings on the breakdown potential (Eb) of NiTi wires measured in artificial saliva. It is shown that coatings potentiostatically deposited at −1.30 V/SCE from a 0.0625 mol L−1 ZrOCl2·8H2O solution can offer an outstanding improvement in the Eb of NiTi. Starting from a very low value of +0.16 V/SCE for uncoated specimens, the Eb was found to increase as a linear function of the deposition time up to a maximum value of +1.10 V/SCE (ca. 1.00 V higher) for NiTi samples whose ZrO2 coating was deposited during 40 min. The electrolytic ZrO2 deposits were in the amorphous state, and they were not annealed in order to maintain mechanical and shape memory properties of the substrate.