Hydrothermal pre-treatment fortified binding strength and corrosion resistance of phenolic-amine crosslinking coating on biomedical magnesium alloy

Abstract

Biomedical magnesium (Mg) alloys are promising biodegradable vascular stent materials, but their applications are limited by rapid degradation. In this study, we construct a composite consisting of a hydrothermal and a phenolic-amine cross-linked coating to reduce the corrosion rate of Mg alloys. The hydrothermal coating is prepared underneath the phenolic-amine crosslinking coating to serve as an embedded layer on the Mg-alloy substrate. The hydrothermally treated surface provides a corrosion-resistant coating with a dense microporous structure, thereby increasing the contact area and enhancing the reaction efficiency of the substrate. The adhesion and bonding strength of the composite coating and the substrate are fortified and the bearable loading force is increased from 40 N to 100 N, as compared to the samples without any hydrothermal transition layer. Moreover, the corrosion rate of the modified samples decreases from 0.35 mm/year to 0.06 mm/year. The results show that the composite coating, which includes a hydrothermal transition layer, can effectively improve the adhesion of the surface coating to the substrate and further enhance the corrosion resistance of the Mg alloy. This work provides a new approach for the surface modification of biomedical Mg alloys.