Enhanced corrosion resistance of bio-piezoelectric composite coatings on medical magnesium alloys

The surface of a medical magnesium alloy treated by micro-arc oxidation was coated with magnesium phosphate-based bio-piezoelectric bone cement. The high tensile adhesive strength of the obtained composite coating was 6.83 MPa due to mechanical locking and its chemical reaction. The corrosion degradation property of the bio-piezoelectric composite coating in simulated body fluid improved because the negative surface charge after polarization led to the balance between degradation and deposition rates during apatite deposition. After the coating was soaked in simulated body fluid (SBF) for 7days, the weight loss rate of the sample considerably decreased to 1.03%, and the average corrosion rate decreased to 3.33 mm/year.