Ag-Loaded ZSM-5 Zeolite Functionalized Microarc Oxidated Coatings: A Multifunctional Strategy for Enhanced Antibacterial and Corrosion Resistance of Titanium Alloys

Titanium alloys exhibit excellent mechanical properties, good corrosion resistance and biocompatibility, making they widely used in medical field. Nevertheless, their practical application is frequently constrained by bacterial infection and corrosion issues in physiological environments. To overcome these challenges, this study proposes a novel multifunctional strategy involving the incorporation of Ag + -loaded ZSM-5 zeolites into a micro-arc oxidated (MAO) coating on the surface of titanium alloy to fabricate Ag/ZSM-5@MAO-Ti composite coating. The microstructure, mechanical properties, and functional characteristics of the coating were systematically characterized. Analysis confirmed that Ag/ZSM-5 were evenly dispersed within the MAO coating while preserving the crystal structure intact. By leveraging the mechanical interlocking effect, the particles were securely retained within the micropores of the MAO layer after in-situ hydrothermal secondary growth. The composite coating exhibited exceptional adhesion to the titanium alloy substrate, with an average bond strength of 64   N. Owing to the inherent hydrophilicity of zeolites, the composite coating demonstrated significantly enhanced hydrophilicity with a contact angle of 12.9±0.7°. Antimicrobial tests results revealed that the coating achieved an inhibition rate of more than 99.99% against Escherichia coli (E. coli), and the sustained release of Ag⁺ ensures long-term antimicrobial efficacy. Furthermore, the composite coating displayed superior corrosion resistance in phosphate buffer solution (PBS). In summary, the Ag/ZSM-5 modified MAO coating substantially enhances the antimicrobial properties and corrosion resistance of titanium alloy, offering a promising strategy for the development of advanced medical devices.