Dr. Rongchang Zeng, Professor, School of Materials Science and Engineering, Shandong University of Science and Technology, China

Title: Hereditary corrosion resistance and biocompatibility of Ca and Ce-doped phosphate conversion coatings on magnesium alloys

Abstract: Magnesium (Mg) and its alloys have lightweight, high specific strength and excellent biocompatibility, can be utilized in transportation, 3C products and degradable biomaterials. However, they are susceptible to corrosion in chlorine-bearing solutions due to their low potential. The low corrosion resistance restricts their wide applications. Environmentally-friendly and low cost coatings are ideal strategy for the promotion to the use of Mg alloys. Chemical conversion coatings have been extensively applied on structural metals. Novel phosphate conversion coatings have been developed through doping with Ca and Ce. The corrosion behavior of chemical conversion coatings on magnesium alloys relates to the microstructure characteristic and corrosion resistance of their substrates. Refined and elemental dispersive distribution phosphate chemical conversion coatings have been achieved through doping with Ca and Ce. The hereditary relationship of microstructural and chemical composition factors as well as corrosion resistance of the Mg alloys (including extruded AZ31 sheets, AZ31 tubes and AM30 tubes) with that of the coatings is established. The formation mechanism of the coatings is proposed. The Ca and Ce-doped phosphate conversion coatings on magnesium alloys exhibits good biocompatibility.

Keywords: magnesium alloy; coating; corrosion resistance; biomaterial