Mg–Nb alloy films: Structure and stability in a balanced salt solution

• Mg–Nb alloy films were produced in a wide range of Nb concentrations.
• The alloys are promising for in vivo applications.
• Passivity was reached in a balanced salt solution when Nb/Mg atomic ratio was one quarter.
• A distinctive Nb-enriched network was found within the alloys.

Mg–Nb alloy films have been formed in a wide range of Nb concentrations using the magnetron sputtering technique. The systems are of interest in biomedical applications in-vivo. A distinctive distribution of Nb over Mg matrix was determined by scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Corrosion behaviour was studied in a balanced salt solution with a physiological pH. Experiments were performed by solution analysis, dc-voltammetry, quartz crystal microgravimetry, X-ray photoelectron spectroscopy and electron microscopy. Quasi-passivity was reached at Nb/Mg atomic concentration ratio of one quarter. It has been shown that corrosion activity could be adjusted according to biomedical requirements by varying Nb concentration.