Morphology and structural development of reduced anatase-TiO₂ by pure Ti powder upon annealing and nitridation: Synthesis of TiO_x and TiO_xN_y powders

It is well known that nitriding of titanium is suitable for surface coating of biomaterials and in other applications such as anti-reflective coating, while oxygen-rich titanium oxynitride has been applied in thin film resistors and photocatalysis. Thus in this work anatase was reduced with pure titanium powder during annealing in argon. This was done to avoid any metallic contamination and unwanted residual metal doping. As a result, interesting and different types of particle morphology were synthesized when the pre-milled elemental anatase and titanium powders were mixed. The formation of metastable face centred cubic and monoclinic titanium monoxide was detected by the X-ray diffraction technique. The phases were confirmed by energy dispersive X-ray spectroscopy analysis. Raman analysis revealed weak intensity peaks for samples annealed in argon as compared to those annealed under nitrogen. - Graphical abstract: Display Omitted - Highlights: • Reaction of TiO₂ and Ti induced metastable FCC and monoclinic TiO_x. • Compositions of mixed powder were prepared from the unmilled and pre-milled powders. • Nitridation of TiO_x yielded TiO_xN_y phase. • Mixed morphology was observed on all three powder samples