Enhancing the performance of calcium phosphate coating on a magnesium alloy for bioimplant applications

A magnesium alloy, AZ91, was coated with calcium phosphate using pulse-potential method in ethanol containing coating solution for improved degradation resistance of the alloy in body fluid. Electrochemical impedance spectroscopy and potentiodynamic polarization experiments in simulated body fluid suggested that the degradation resistance of the pulse-potential coated alloy was higher than that of the constant-potential coated alloy. Scanning electron microscopy analysis revealed that the morphology of the pulse-potential coating played a critical role in enhancing the coating performance in simulated body fluid.

► Synergetic effect of pulse-potential and ethanol addition to coating solution.
► The CaP particles were large, flat and closely packed.
► The CaP coating exhibited relatively high in vitro degradation resistance.