Synthesis and characterization of corrosion-resistant and biocompatible Al2O3–TiB2 nanocomposite films on pure titanium

Abstract

Alumina is widely used as a coating on a metal implant due to its favorable mechanical and biological properties. In this research, in order to improve mechanical and biological properties of alumina, a composition of nanoparticles of alumina (instead of microparticles) and titanium diboride micro powder is introduced. The atmospheric plasma spray (APS) technique was applied to deposit Al2O3–TiB2 on the pure titanium substrate. The properties of Al2O3–TiB2 nanocomposite coatings with various weight percent of TiB2 (20, 30 and 40 wt%) were experimentally studied. The characteristics of nanocomposite films of TiB2 (20, 30 and 40 wt%) were analyzed using Field Emission Scanning Electron Microscopy (FE-SEM), energy dispersive electron spectroscopy (EDX) and X-Ray Diffraction (XRD) tests. The XRD spectra exhibited that in addition to alumina and titanium diboride, the films contained titania. Thickness and morphology of the films were calculated from FE-SEM images and the thickness of the optimized coating (Al2O3-30 wt% TiB2) was about 30–45 μm. Also, the roughness, corrosion resistance, hardness and cytotoxicity (MTT) tests were studied. The highest of hardness and roughness of the samples were obtained from Al2O3-30 wt% TiB2. According to the obtained results from the polarization test, Al2O3-30 wt% TiB2 coating had the highest corrosion resistance (222558.9962 Ω cm2). Therefore, the toxicity of Al2O3-30 wt% TiB2 was investigated as the optimized coating and the results confirmed its non-toxicity and biocompatibility.