Chemistry reaction processes during combustion synthesis of B2O3-TiO2-Mg system

In this paper, combustion synthesis method was used to synthesize TiB2 ceramic powder from various oxides. Thermal analysis methods were employed to reveal the chemical reaction processes, a high-speed image recorder was used to monitor and analyze the features of combustion processes. Study results indicated that in B2O3-TiO2-Mg system, B2O3 was reduced to elemental B and MgB2 in one step and TiO2 was reduced to element Ti through following steps: TiO2 --> Ti3O5 --> Ti2O --> Ti, and then, TiB2 was formed by reaction Ti + 2B --> TiB2 and Ti + MgB2 --> TiB2 + Mg. In synthesis processing, Mg plays a important role in controlling the mineral phase component of synthesized production and combustion processing. The propagating combustion wave model was found to become unstable with increasing diluent additive amount in raw mixture. (C) 2002 Elsevier Science B.V. All rights reserved.