Advancement of Powder Spheroidization Process Using a Small Power DC-RF Hybrid Plasma Flow System by Sinusoidal Gas Injection

Abstract

The effect of sinusoidal central gas injection on the in-flight alumina spheroidization process was experimentally clarified by using DC-RF hybrid plasma flow system under constant low input power. Spheroidization ratio was evaluated with correlating to frequency and amplitude of sinusoidal central gas injection, DC arc voltage, and particle size distribution. Spheroidization ratio improves through active mixing of DC-RF hybrid plasma flow with powder by injection of sinusoidal central gas for DC plasma jet forming. The maximum spheroidization ratio of 99 % for processed powder collected at z = 120 mm was obtained by giving the sinusoidal central gas injection at f c = 2 Hz with amplitude of ± 20 %.