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

Abstract X-ray diffraction (XRD), differential thermogravimetric analysis (DTA) and differential scanning calorimetric analysis (DSC) were performed on 8Al–TiO 2 – x MgO mixtures and compacted sample treated in nitridation furnace, to foster an understanding of the reaction path involved in the MgAl 2 O 4 /TiN composite-forming aluminothermic reduction and nitridation. The results show that: (a) when N 2 gas is apt to diffuse in green body, first, aluminum powders react with N 2 to yield AlN, replacement reaction between AlN and TiO 2 occurs, and then TiN and Al 2 O 3 are produced; (b) when N 2 gas diffusion is difficult, Ti element formed by Al reduction of TiO 2 reacts with N 2 to form TiN. The results also show that MgO facilitates TiN formation by removal of intermediates.