Corrosion behaviour of sputter-deposited Mg–Zr alloys in a borate buffer solution

Corrosion behaviour of sputter-deposited Mg–Zr alloys was examined in a borate buffer solution of pH 8.7. XRD measurements showed that the alloys were supersaturated with Zr. The addition of 29 at.% Zr or more was very effective in increasing the corrosion resistance of Mg by more than four orders of magnitude. XPS analysis of spontaneously formed passive films revealed that the passive film consisted of double oxyhydroxide composed of enriched tetravalent Zr and divalent Mg cations. The enrichment of Zr cations in the passive film is responsible for the enhanced corrosion resistance of Mg–Zr alloys.

► Sputter deposited Mg–Zr alloys were developed as corrosion resistant magnesium-based alloys. ► The alloys have single phase solid alloy structure. ► Addition of 29 at.% Zr was effective in increasing the corrosion resistance of Mg by about four orders of magnitude. ► Formation of double oxyhydroxide passive film was responsible for the corrosion resistance of the alloys.