Effect of the solid precursors on the formation of nanosized TiBx powders in RF thermal plasma

Continuous synthesis of TiBx (x≈0.5–2) nanoparticles from various low cost solid precursors such as titanium and titanium dioxide admixed with boron and/or carbon in radiofrequency thermal plasma was studied. Feasibility of TiB2 formation was predicted by thermodynamic equilibrium calculations in the 500–5000 K temperature range. In all the investigated system high temperature reactions resulted in nanometer-sized TiBx powders with a mean size varying between 13 and 83 nm. The yield of particular runs ranged from 38% to 97%. Among the synthesized products in addition to TiBx, oxidized precursor residues were also found in smaller quantities. Although addition of carbon to the precursors could not completely prevent surface oxidation of boride particles, it contributed to the reduction of the mean particle size of the formed TiB2.