Microstructure, anti-corrosion and biological performance of Ag, Zn Co-doped titania coating: The influence of Zn contents

Abstract Bio-medical materials with sufficient antibacterial performance and osteogenic activity are desirable for orthopaedic implantable devices. In the present work, titanium (Ti) surface was modified through micro-arc oxidation in an electrolyte containing Ag nanoparticles (NPs) and disodium zinc ethylenediaminetetraacetate tetrahydrate (Na2Zn-EDTA) to fabricate Ag, Zn co-doped titania coating, with the influence of Na2Zn-EDTA content on its microstructure, corrosion behaviour and biological performances investigated systematically. By increasing the amount of Na2Zn-EDTA from 5 g/L to 50 g/L, the coating exhibits a significantly reduced average pore size along with a decreased coating thickness. Further, unlike micro-sized dicalcium phosphate dehydrate (DCPD) crystals and Ag NP clusters for the coating produced by 5 g/L Na2Zn-EDTA, both Ag NPs of a reduced amount and nano-sized amorphous Ca and P-rich components were observed on the coating surface when the electrolyte containing 50 g/L Na2Zn-EDTA was used. The microstructural variation inevitably leads to the modification of its performances. The high amount of Na2Zn-EDTA results in a bio-ceramic characterized by higher corrosion resistance, enhanced antibacterial capability and improved osteogenic activity relative to that fabricated with the addition of a low amount of Na2Zn-EDTA. Therefore, this work provides a new strategy for the fabrication of bio-ceramics on Ti-based implants.