Abstract: TiB₂ powder was prepared by SHS-metallurgy. The relative reaction systems were analyzed by DTA. The combustion products and leachable products were analyzed and characterized by XRD, SEM and granularity distribution. The results indicate that SHS reaction of Mg-TiO₂-B₂O₃ system takes place through solid-liquid-liquid-solid reaction process. The combustion products consist of TiB₂, MgO and a little Mg₂TiO₄ & Mg₃B₂O₆. The TiB₂ particles become thinner when the sample pressure increases; TiB₂ particle becomes thinner when adding MgO to the reaction system and TiB₂ particles become bigger when adding TiB₂ to the reaction system. The microstructure of combustion products and the forming mechanism of the different micro-regions were analyzed by Micro-region-technology based on SEM. The growth mechanism of TiB₂ can be determined that one is growing in particle-particle interfaces and the other is growing within particles.

Key words: TiB2, self-propagating high-temperature synthesis, DTA, growing mechanism