In Vivo Corrosion Resistance of Ca-P Coating on AZ60 Magnesium Alloy

Magnesium-based alloys are frequently reported as potential biodegradable orthopedic implant materials. Controlling the degradation rate and mechanical integrity of magnesium alloys in the physiological environment is the key to their applications. In this study, calcium phosphate (Ca-P) coating was prepared on AZ60 magnesium alloy using phosphating technology. AZ60 samples were immersed in a phosphating solution at 37 ± 2 °C for 30 min, and the solution pH was adjusted to 2.6 to 2.8 by adding NaOH solution. Then, the samples were dried in an attemperator at 60 °C. The degradation behavior was studied in vivo using Ca-P coated and uncoated magnesium alloys. Samples of these two different materials were implanted into rabbit femora, and the corrosion resistances were evaluated after 1, 2, and 3 months. The Ca-P coated samples corroded slower than the uncoated samples with prolonged time. Significant differences (p < 0.05) in mass losses and corrosion rates between uncoated samples and Ca-P coated samples were observed by micro-computed tomography. The results indicate that the Ca-P coating could slow down the degradation of magnesium alloy in vivo.