Electrophoretic Deposition of Hydroxyapatite Coatings on AZ31: The Effect of Nanoparticle Multiple Coating Approach

Abstract

Magnesium and its alloys are potential biodegradable implant materials. However, they are characterized by rapid degradation in the electrolytic environment of the body. This phenomenon might result a sudden implant failure before bone restoration was complete, or inflammation subsided. This research will explore ways to improve the corrosion resistance of AZ31 magnesium alloy by improving the coating layer of hydroxyapatite (HA) through multiple coating layers by an electrophoretic deposition (EPD) process. In this study, the quality of the coating layer was improved by multiple coating processes without using any binders. X-ray diffraction spectrometer (XRD) showed that an amorphous structure of HA was successfully deposited on the AZ31 alloy. Scanning electron microscopy (SEM) has been used to observe that the morphology of the AZ31 alloy coated with multiple layers of HA has a denser coating structure with improved adhesion at the interface as compared to the single coating layer. A denser coating structure with greater bonding between the coating layer and the substrate is expected to protect the substrate from a high corrosion rate, thus resulting in a longer period of biodegradation as in implant in the electrolytic environment.