Reaction path in the aluminothermic reduction nitridation reaction to synthesize MgAl2O4/TiN composite

X-ray diffraction (XRD), differential thermogravimetric analysis (DTA) and differential scanning calorimetric analysis (DSC) were performed on 8Al-TiO2-xMgO mixtures and compacted sample treated in nitridation furnace, to foster an understanding of the reaction path involved in the MgAl2O4/TiN composite-forming aluminothermic reduction and nitridation. The results show that: (a) when N2 gas is apt to diffuse in green body, first, aluminum powders react with N2 to yield AlN, replacement reaction between AlN and TiO2 occurs, and then TiN and Al2O3 are produced; (b) when N2 gas diffusion is difficult, Ti element formed by Al reduction of TiO2 reacts with N2 to form TiN. The results also show that MgO facilitates TiN formation by removal of intermediates.