The impact of different volume fractions of crystalline structures on the electrochemical behaviour of Mg67Zn29Ca4 alloys for biomedical applications

In this work, the influence of various volume fractions of the crystalline phase in an amorphous matrix of Mg67Zn29Ca4 alloys was investigated for its corrosion resistance for biodegradable applications. An amorphous Mg67Zn29Ca4 alloy was successfully fabricated using melt casting into a copper mould. Then, to obtain different ratios of the crystalline phase in an amorphous matrix, the obtained amorphous rods with 3 mm diameters were annealed at 190, 230, 250, and 400 degrees C. The volume fraction of the crystalline phase was measured by X-ray diffraction, and the microstructures of the obtained alloys were determined based on scanning electron microscopy images. Electrochemical testing was conducted in simulated body fluid at 37 degrees C. This report shows that the ratio of the volume fractions of amorphous and crystalline phases in alloy microstructures strongly influences their corrosion behaviours. The alloy with a fully amorphous structure was the most resistive in the analysed media.