The study of nano particles fabrications using the RF thermal plasma torch

Abstract

Summary form only given. We fabricated nano-sized silicon and nickel powders using a radio frequency (RF) induction thermal plasma process with 10~30 micro-size powders as precursor materials. The several key variables with the nano-particle size such as RF power, working pressure, and flow rate of carrier, central, sheath, and quenching gas were investigated and characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). As a result, we found the average particle size of silicon and nickel powders distribute in the range of 40~100 nm and 20~50 nm, respectively. The color of nano silicon powders was changed from dark gray to yellow brown with particle size variation from micro-scale to nano-scale, while the color of nickel powder was not changed. We also used computational fluid dynamics (CFD) for more information on the temperature and fluid behavior in torch. The position of a powder injection tube, the plasma discharge characteristics with various input-current and length of a ceramic tube, and the characteristics of plasma temperature with the process gas flow rate were simulated.