Effect of acidic fluoride solution on the corrosion resistance of ZrTi alloys for dental implant application

• Thermal oxidation of ZrTi alloys improves corrosion resistance in fluoridated saliva.
• Passive behaviour of thermally oxidized alloys conversely to as cast materials.
• Localized breakdown of passive film at high anodic overpotential.
• Protective oxide film contains both TiO2 and ZrO2 in all cases.

The electrochemical behaviour of Zr5Ti, Zr25Ti, and Zr45Ti, with and without surface modification were monitored in acidic artificial saliva (pH = 3) containing NaF concentrations 0.2, 0.5, and 1 wt.%, simulating the fluoride concentrations in dental rinses. A passive behaviour for thermally oxidized ZrTi alloys was found using EIS, and XPS data show that the protective oxide film contains both TiO2 and ZrO2, though titanium contents in the outer layer bigger than those in the base alloy result from thermal oxidation. High corrosion resistance to acidic fluoridated environments of ZrTi alloys treated using thermal oxidation in air at 500 °C.

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