Phytic acid-cerium composite coatings modified with silver nanoparticles for corrosion protection and antibacterial activity on AZ91D Mg alloy

This work presents the synthesis and evaluation of phytic acid–cerium composite coatings with anticorrosive properties on AZ91D magnesium alloy. The coatings were formed by a simple one-step electrochemical process from a single solution combining phytic acid and cerium ions, aiming to enhance corrosion resistance in a simulated physiological environment. The influence of two different cerium salt concentrations in the phytic acid coating bath on the corrosion behavior was investigated. The results demonstrate that the incorporation of 10 mM Ce(NO₃)₃ into the phytic acid bath reduces the corrosion current density by approximately five orders of magnitude compared to the uncoated alloy. Electrochemical impedance spectroscopy revealed the development of a self-healing behavior, attributed to the deposition of corrosion products and cerium-based compounds on the substrate surface. Furthermore, the modification of the phytic acid-cerium coating with silver nanoparticles imparted notable antibacterial activity against Escherichia coli and Staphylococcus aureus . Overall, this study reports the formation of a phytic acid–cerium composite coating obtained in a single step from a combined solution and applied to a magnesium-based alloy, offering a simple strategy for corrosion protection and functional surface modification of Mg alloys.