Improving the corrosion resistance and biocompatibility of magnesium alloy via composite coatings of calcium phosphate/carbonate induced by silane

Magnesium alloy is a potential biodegradable implant material, which has attracted wide attention because of its excellent mechanical properties, degradability and biocompatibility. However, its uncontrolled degradation and fast hydrogen gas production impede the clinical application. In order to solve this problem, we developed two composite coatings, the silane coupling agent-dicalcium phosphate dihydrate (SCA/DCPD) coating and the silane coupling agent‐‑calcium carbonate (SCA/CaCO3) coating. The morphology, composition, corrosion resistance and biocompatibility of the coated samples were systematically studied. The results showed that these two kinds of coatings could reduce the degradation of magnesium alloy, and have their own advantages. The SCA/DCPD coated sample showed better corrosion resistance, while the SCA/CaCO3 coated sample obtained better biocompatibility. Our research provided a novel sight and choice to design the biocompatibility coating and promote the clinical application for magnesium alloy.