Insight into the corrosion behaviour and degradation mechanism of pure zinc in simulated body fluid

Zn is considered as a promising degradable biomaterial. However, concerns exist for its application as the degradation mechanism of pure Zn in physiological solutions is still not clear. Results indicated that the corrosion product film showed a laminated structure with complex layers, which were ZnO/Zn(OH)2, a Ca/P phase, zinc compounds, and a Ca/P phase from the inside out, respectively. The localized corrosion initiated at grain boundaries and expanded towards the interior of grains with higher corrosion susceptibility, or advanced towards the depth. Additionally, the nature of the corrosion product film and localized corrosion synergistically determined the degradation rate.