Dual self-healing inorganic-organic hybrid coating on biomedical Mg

Local corrosion of coated Mg alloys appears as aggressive solutions penetrate the coating-substrate interface, which might accelerate the premature failure of coated Mg alloys. In this work, Mg corrosion by-products, including pH increase and Mg2+ enrichment, were attempted to act as dual stimuli for coating self-healing. We prepared DCPD/HxPhy (dicalcium phosphate dihydrate/phytic acid) hybrid coating as anti-corrosive self-healing coatings for regulating Mg degradation. pH increase stimulated Ca2+ and PO43- ion release from DCPD and apatite formation for local corrosion elimination. Besides, HxPhy-containing compounds were regulated by Mg2+ ion enrichment and transformed into Mg-HxPhy chelate compounds for enhanced self-healing behavior.