Synthesis and degradation behaviour of Zn-modified coating on Mg alloy

Abstract

This study aimed to control the degradation of Mg–Zn–Ca alloy and improve its biocompatibility using a biodegradable Zn-modified calcium phosphate coating via dual-pulse electrodeposition. The formation mode and process of the coating were studied herein. Scanning electron microscopy revealed that the coating particles were compactly and neatly packed, and X-ray diffraction analysis, transmission electron microscopy, Fourier transform infrared spectrophotometer and X-ray photoelectron spectroscopy revealed that the coating comprises CaZn2(PO4)2•2H2O. The introduction of Zn changes the formation mechanism of coating. The degradation behaviour of the coated Mg alloy was investigated via immersion test and electrochemical test in simulated body fluid. The results show that this non-stoichiometric Zn-modified calcium phosphate coating is biodegradable and has a better protective effect. In addition, the Zn-containing coating has hydrophilic property which is beneficial to enhance the cellular response to the implant’s surface and increase apatite formation rate.