Preparation and Evaluation of ZnO-Strontium Composite Coating on Pure Zinc for Orthopedical Applications

Zinc and its alloys have been regarded as an alternative option for biodegradable implant materials to magnesium and iron-based alloys due to their promising degradation rate. However, poor osseointegration with bone tissue limits their further clinical application. Considering the biofunction of strontium (Sr), namely promoting the formation of bone tissue, in this work, a ZnO-Sr composite coating was prepared on pure Zn via anodic oxidation to boost bioactivity. Surface morphology and composition of the layer were examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical measurements were carried out to assess the corrosion behaviour. Long-term immersion tests in simulated body fluid (SBF) for up to 21 days were conducted to evaluate the in vitro bioactivity. Corrosion morphology and corrosion products were studied to reveal the corrosion mechanism. The results demonstrated that the Sr-ZnO coating optimized the corrosion rate and enhanced the bioactivity of the substrate, improving its potential for orthopedic applications.