Study of corrosion, biological and mechanical properties of biodegradable Zinc-Iron alloys with medical applications

Biodegradable metals used in orthopedics have gained a lot of attention in recent years mainly due to their good mechanical properties and biocompatibility [1]. Among them, zinc stands out with its excellent corrosion behavior in a physiological environment. However, the mechanical properties of pure zinc are unsatisfactory. This deficiency can be solved by alloying with different metals [2]. This work is devoted to the preparation and complex characterization of Zn-Fe binary alloys prepared from the elemental powders. Samples were sintered at 350 °C and their corrosion, mechanical and biological properties were tested. The microstructure and composition of the alloys were studied by SEM, EDX, and XRD methods. Corrosion properties were evaluated by electrochemical polarization tests in simulated body fluids at 37 °C and pH = 7,4. Besides that, the hemocompatibility of the samples was studied using healthy sheep blood. It was found that iron addition (1,2,5 or 10 wt.% respectively) did not enhance the mechanical properties. Corrosion rates of the alloyed samples were greater than that of pure zinc which was attributed to the micro-galvanic effect induced by the presence of the intermetallic Zn₁₁Fe phase. Platelet adhesion tests of pure zinc and Zn-Fe alloys showed good anti-platelet properties. Overall, Zn-Fe alloys should serve as potential biodegradable scaffolds after their further in vivo biocompatibility tests.