Effect of cell structure on mechanical and bio-corrosion behavior of biodegradable Mg-Zn-Ca foam

This study investigates the fabrication, mechanical properties, and corrosion behavior of biodegradable Mg-1.5Zn-1Ca alloy foams. A series of the alloy foams produced with spherical cells in five different cell sizes between 600 and 2800 mu m using the infiltration process. The compressive mechanical properties and corrosion behavior of the foams were evaluated. It was found that increasing the porosity content of the foams led to decreasing the mechanical properties, while the pore size had no significant effect on the mechanical properties. Compared to a pure Mg foam, the precipitation of eutectic phases (alpha-Mg + Mg6Zn3Ca2 + Mg2Ca) at the grain boundaries of the alloy foams caused a higher compressive strength. Additionally, the Mg-Zn-Ca alloy foams significantly showed a higher corrosion resistance than the pure foam due to the beneficial effects of zinc and calcium. It was also found that an increase in the pore size of the alloy foam increased the corrosion resistance. Accordingly, the highly porous foam with a pore size of similar to 2800 mu m and porosity content of similar to 64% exhibited a corrosion rate near the dense Mg-Zn-Ca specimen.