Low-temperature Solid-state Synthesis of Nanometer TiB$lt;inf$gt;2$lt;/inf$gt;-TiC Composite Powder

TiB 2 -TiC composite powders were prepared at low temperature in the Ti-B system with the PTFE polytetrafluoroethylene (polytetrafluoroethylene) as a chemical activator. Reaction temperature, phase composition and morphology were measured via differential thermal analysis, X-ray diffraction and field emission scanning electron microscopy (FESEM) in order to explore the reaction mechanism, respectively. Actual solid-state reaction synthesis experiments were carried out for the same composition in an argon atmosphere furnace. It was found that TiB 2 -TiC composite powder could be synthesized successfully at 550 by adding 10wt% PTFE into the initial reactant Ti-B mixture. The FESEM image showed that the average size of the product was smaller than 400 nm. According to differential thermal analysis results, the combustion synthesis mainly includes two reaction processes: firstly, the initial reaction between titanium and PTFE particles resulting in great amounts of heat release; subsequently, the released energy triggers the solid-state reaction between titanium and boron particles to form TiB 2 .