Fabrication and characterization of Sr-modified Bredigite/chitosan nanocomposite coatings on AZ31 alloy via electrophoretic deposition for bone applications

Abstract

Biosilicate materials have garnered significant interest for their potential to enhance corrosion resistance, particularly in biomedical applications. In this study, the surface of AZ31 magnesium alloy was modified with Sr-doped bredigite/chitosan nanocomposite coatings to improve corrosion resistance for use in biodegradable implants. Bredigite calcium silicate (Ca7-xSrxMgSi4O16), synthesized via a combustion sol–gel method with varying strontium doping levels (x = 0, 0.05, 0.1, 0.2, 0.4), was combined with chitosan and applied to magnesium substrates through electrophoretic deposition. Various techniques were employed to analyze and compare the chemical composition, verifying the incorporation of strontium into the bredigite structure. Electrochemical analysis demonstrated that the Sr-doped Bredigite/chitosan coatings significantly enhanced the corrosion resistance of the magnesium alloy in simulated body fluid. Polarization tests revealed that coatings containing 0.2 strontium substantially reduce the corrosion current density from 17.12 μA/cm² to ~1.37 μA/cm2 . These coatings, exhibiting remarkable bioactivity and corrosion protection, hold strong potential as candidates for biodegradable magnesium-based implants in biomedical applications.