Tuning biomechanical behavior and biocompatibility of Mg–Zn–Ca alloys by Mn3O4 incorporated plasma electrolytic oxidation coatings

In this study, the mechanical behavior and biocompatibility of plasma electrolytic oxidation (PEO)-coated Mg-Zn-Ca alloy specimens were investigated. The coatings were synthesized by incorporating KMnO4 and Mn3O4 nanoparticles into an electrolytic solution. An indentation test revealed a significant increase in the reduced elastic modulus of the PEO coatings with incorporated Mn3O4 under various loads. This increase was attributed to the higher coating thickness and reduced porosity achieved by the addition of Mn-based additives to the electrolyte. The composite PEO coatings prepared with Mn3O4 nanoparticles exhibited a more pronounced reduction in elastic modulus under pressure. Wettability tests showed that the prepared coatings maintained their hydrophilic nature with water contact angles in the range of 25–63º. The presence of Mn3O4 in the PEO coatings provided a conducive environment for cell viability. The enhanced biocompatibility of the composite coatings achieved by incorporating KMnO4 into the electrolyte was particularly noteworthy. This improvement was attributed to the controlled release of Mn ions, which generates a microenvironment that favors cellular activities. The study showed that incorporating Mn3O4 into PEO coatings enhances mechanical properties, preserves hydrophilicity, and improves biocompatibility, thus indicating its potential for orthopedic implant applications.