Effects of Ag, Cu or Fe addition on microstructure and comprehensive properties of biodegradable Zn-Mg alloy

Abstract

In recent years, Zn-0.5 wt%Mg alloys have drawn a lot of attention as a potential candidate in biodegradable implant applications as it demonstrated more corrosion resistant property in comparison to Fe- and Mg-based alloys. Zn-0.5 wt%Mg based alloys were fabricated through powder metallurgy. This work examined the impact of the micro-alloying metals Cu, Fe, and Ag on Zn-Mg alloys. Moreover, the structure, absorbing properties, morphology, electrochemical properties, electrical properties, and wettability were also investigated. All fabricated Zn-0.5 wt%Mg alloys formed a primary phase of Mg2Zn11 and secondary phase of MgZn2. A minor phase of Zn was also identified in XRD analysis. Optical analysis showed that the Zn-0.5 wt%Mg-0.2 wt%Cu alloy gave a strong peak of absorbance at a short wavelength of 230 nm which is due to its colour. All alloys sintered at 350 ◦C displayed micro-needles having size in the range of 1.82–26.2 µm in SEM analysis. Zn-0.5 wt% Mg-0.2 wt% Cu alloy offered 140 Hv value of Vickers hardness. The electrochemical test findings measured corrosion resistance and most corrosion resistant material was Zn-0.5 wt%Mg-0.2 wt%Cu alloy with corrosion rate 0.0120 mm/year. Zn-0.5 wt%Mg-0.2 wt%Cu offered the conductivity with the least value of 7.45 ×10−12 Ω−1m−1and highest value of resistivity at 1.335 ×1011Ω-m, based on electrochemical study. All fabricated biodegradable Zn-0.5 wt%Mg alloys had an angle less than 90, indicating hydrophilicity as determined by wettability studies. Zn-0.5 wt%Mg-0.2 wt%Cu is the most suitable alloy in cardiovascular stent and orthopaedic implant applications.