Effect of grain size on degradation behavior of Mg-3Zn-0.2Ca-0.2Mn alloy for biomedical application

In this paper, Mg-3Zn-0.2Ca-0.2Mn alloys with similar second phase content and different grain sizes were obtained through the solid solution process, and the alloys with different grain sizes were subjected to immersion and electrochemical experiments in Hank’s simulated body fluid. The effect of grain size on the degradation behavior of biomedical Mg-3Zn-0.2Ca-0.2Mn alloy was investigated and analyzed. The electrochemical experiment shows that the smaller the grain size of the alloy, the smaller the corrosion current density, and the larger the impedance value. The immersion experiment and the observation of the surface morphology shows that, with the decrease of the grain size, the degradation rate of the alloy slows down, the surface corrosion pit size is smaller and more uniformly distributed, and the corrosion resistance of the alloy is better. In the process of alloy degradation, the grain size affects the corrosion resistance of the alloy by affecting the density and integrity of the degradation product film. The smaller the grain size of the alloy, the denser and more complete the product film formed on the surface, and the Cl⁻ adsorbed on the surface is not easy to penetrate into the interior, which helps to improve the corrosion resistance of the alloy.

Duke Scholars

Author Zhaohui Wang Pathology