Ambient-temperature mechanochemical formation of titanium nitride-alumina composites from TiO₂ and FeTiO₃

The fabrication of a homogeneous submicrometer-sized powder composed of nanocrystalline (<10 nm) alumina and titanium nitride during high-energy ball-milling is reported in this paper. The starting materials were rutile (TiO₂) and aluminum powder. A similar composite with iron was also produced using the mineral ilmenite (FeTiO₃) as the starting material. The powders were ball-milled together under a nitrogen atmosphere for 100 h in a laboratory-scale mill and subjected to thermal analysis and isothermal annealing at up to 1200°C. X-ray diffraction showed that all of the phases formed within the milling step and underwent grain growth on annealing. Differential thermal analysis indicated no residual elemental aluminum, confirming that the reaction was completed during the milling operation.