Corrosion Behavior and Cytotoxicity of Mg-3Zn-0.5Zr Alloy in SBF

A Mg-3wt%Zn-0.5wt%Zr alloy was fabricated and its corrosion and electrochemical behavior in SBF were studied, and the extracting method was used to evaluate the cytotoxicity in vivo. The results show that the Mg-3Zn-0.5Zr alloy reacted with SBF rapidly and formed a dense Mg(OH)(2) layer, and slight pitting occurred on the alloy surface after 5 d immersion, while the pitting did not expand with the time increasing. The open circuit potential curves fluctuated slightly and the mass loss of the alloy increased rapidly at the same time. After 12 d, the pitting was found to be repaired, the Ca-P depositions increased, and the appropriate corrosion rate was reduced from the previous 6.5 X 10(-4)cm(-2).h(-1) to 2.0 X 10 cm(-2).h(-1). Mg-3Zn-0.5Zr alloy just performed slight pitting due to the homogeneous distribution of Mg-Zn phase in the matrix and the blocking effect of dense Mg(OH) (2) layer to Cl-, and at last the alloy showed an ability of "self-repaired". The cell proliferation of L929 cells cultured with the extracted medium was high, showing a slight cytotoxicity.