Corrosion behavior and characterization of HA/Fe3O4/CS composite coatings on AZ91 Mg alloy by electrophoretic deposition

In recent years, magnesium (Mg) alloys have received much attention due to their attractive properties, such as biocompatibility and biodegradability. The biodegradable implants have the potential to degrade in the body after completing the healing process. However, the efficient use of Mg alloys as implants are limited due to their low corrosion resistance. In this work, hydroxyapatite (HA) and iron oxide (Fe3O4) composite coatings were fabricated to improve the surface properties and enhance the corrosion resistance of the AZ91Mg alloy. The composite coatings were embedded in chitosan (CS) matrix and developed by the electrophoretic deposition (EPD) method. The Fe3O4 (weight percent, wt %) in HA were varied at different concentrations, i.e., 1, 3 and 5%. Scanning electron microscopy (SEM) images revealed that the composite coatings had a spherical agglomeration and porous nature. Significant decreases in water contact angle values due to greater surface roughness were measured. The Electrochemical test was done in Ringer's solution to evaluate the corrosion behavior. The anticorrosion performance of HA-1wt% Fe3O4 composite coating was (6% and 14%) more compared to 3 wt% and 5 wt% Fe3O4 coated surfaces, respectively. The findings of the study indicate that the proposed HA-Fe3O4-CS composite coating is a favorable candidate for biodegradable implant applications.