Effect of Fe content on physical, tribological and photocatalytical properties of Ti-6Al-xFe alloys for biomedical applications

The aim of the current study is to evaluate the effect of iron content (0, 2, 4, 6 and 10 wt.%) on the structural, tribological and photocatalytical properties of a nanostructured ternary alloy Ti-6Al-XFe, prepared by high energy milling. The alloys' characteristics such as lattice parameters, powder morphologies, surface roughness, relative density/porosity, and microhardness, were evaluated using X-ray diffraction (XRD), scanning electron microscope (SEM), surface profilometry, porosimeter and micro durometer, respectively. The W-H method was utilized to determine the crystallite size. Micro strain was also calculated, which is produced in the lattice due to the diffusion of iron atoms. The photocatalytical characterization was conducted by measuring their absorbance as a function of time using spectrophotometer of visible and ultraviolet light in the wavelength range of 500–800 nm. The tribological characterization was performed using an oscillating tribometer under wet conditions, simulating the human body environment using Phosphate Buffered Saline (PBS) solution with neutral pH 7.4, under different applied loads of 2, 6 and 10 N, respectively. Results showed that the addition of Fe has a significant effect on the structural properties of the developed alloys. The lattice parameter (aα) decreased with increasing Fe content from 2.9493 Å (0 wt.% Fe) to 2.9491 Å (10 wt.% Fe), while the average grain size increased considerably from 6.965 nm (0 wt.% Fe) to 44.42 nm (10 wt.% Fe). The wear test results showed that, friction coefficient and wear rate considerably decreased due to the formation of protective films such as TiO2. The photocatalytical characterization showed that, the degradation of methylene blue (MB) increased with increasing Fe content. The Ti-6Al-4Fe -catalyst gave the best degree of degradation of 90.76% within 60 min, which meant that the decolorization process could be operated rapidly at a relatively low cost without UV irradiation.