Effect of TiO2 Thin Film Coating on AZ91D Alloy and Investigation of Corrosion Behavior, Mechanical Properties, and Biocompatibility

Today magnesium and its alloys have applications in different industries and in addition to this they are used as orthopedic implants. Some of the magnesium alloys can be used as biodegradable implants in the body. Coating of the ceramic material on the magnesium alloys is one of the methods to increase the lifetime of these alloys. In this research, TiO2 thin film was coated on the surface of the AZ91D using the sputtering method. Morphology and cross-section of the coating were done using Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), Vickers hardness test (VM), roughness testing (RT) to investigate the properties of corrosion, polarization tests of corrosion in a simulated body fluid (SBF), adaptability of the sample in the body environment from the toxicity assessment test (MTT) and cellular adhesion. Results from the corrosion test show that the corrosion rate of the coated samples with TiO2 is improved compared to the samples without coating. The percentage of cell survival on the surface of the samples was increased from 80% for the uncoated sample to 90% for the coated sample with TiO2, and the hardness of the coated sample was 119 Hv, and its roughness was 0.12 µm. Applying the coating by increasing the hardness and real contact area and reducing the friction coefficient can increase the wear resistance of the substrate.