The impact of different volume fractions of crystalline structures on the electrochemical behaviour of Mg 67 Zn 29 Ca 4 alloys for biomedical applications

Abstract

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°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°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.