Abstract: Titanium oxide ceramic coatings were prepared by micro-arc oxidation (MAO) in galvanostatic regime on biomedical NiTi alloy produce via powder metallurgy, also the composite coating of HA/TiO2 was prepared on the surface of nitinol using one-step micro-arc oxidation (MAO), the processing time for each case at 280 V was 30 min. The surface of TiO2 coating exhibited a typical porous and rough structure. In this study, the hydroxyapatite, Ca–P precipitate assisted to close the porous and the morphology of the surface coating showed a flower-like structure owing to the incidence of self-assembly because of a long time of precipitate. Surface characterization of the coatings was determined utilizing SEM, XRD, and AFM. The surface morphology, topography, and coating thickness were determined as well. In this study, the properties of corrosion were studied utilizing a potentiostat test unit in Ringer’s solution. Based on the results, the corrosion properties of NiTi alloys considerably improved due to the existence of TiO2 and HA/TiO2 coatings
Conclusion: Based on the obtained result, It was indicated that the layer growth of the TiO2 on NiTi alloy as the base material followed by the MAO technique in quantified parameters has volcanic structures and circular microspores in rough were due to the continuous micro discharges that happened throughout the process. The Rutile and the anatase phases of the TiO2 were presented on the mate rial’s surface after the XRD analysis. Therefore, it was recognized that the TiO2 coating had grown on the surface of the material in the crystal structure. To improve the bioactivity and corrosion resistance of NiTi alloy, the composite coating of HA/TiO2 was equipped on a surface using one step of MAO. The results of the corrosion test in Ringer’s solution observed that TiO2-coated corrosion potentials, base material, and HA/TiO2-coated NiTi alloy were established to be 136 mV, 210.1 mV, and 684.4 mV, respectively. The densities of the current were determined as 1.37, 0.277, and 0.01818 mA/cm2, respectively. Finally, it has been noticed that the composite coating of HA/TiO2 decreases the current density and increases the corrosion potential