Single-step pathway for the synthesis of tungsten nanosized powders by RF induction thermal plasma

Tungsten nanosized powders have been synthesized via a single-step pathway by the RF induction thermal plasma process using APT (ammonium paratungstate) as the precursor. The effects of powder feeding rate and quenching rate on the phase and particle size of the resultant powders were investigated. The phase composition, morphology and particle size distribution of the tungsten nanosized powders were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), and transmission electron microscopy (TEM). The results showed that the crystallized product is spherical tungsten nano-powder with a particle size of less than 50 nm. Moreover the particle size of the tungsten nanosized powders was successfully controlled by adjusting the quenching rate in RF induction thermal plasma system. (C) 2011 Elsevier Ltd. All rights reserved.