Development of a plasma and gas hybrid atomization system for the production of metal powder materials

By applying the optimized DC arc plasma torches (DCAPTs) to gas atomization (GA), the new hybrid atomization (HA) system with three DCAPTs was developed to improve typical GA techniques by using higher superheats from plasma jets with high heat flux. Before mounting on a HA system, the anode structure of a DCAPT was optimized by the experimental investigation with flow simulation. A DCAPT had high thermal efficiency about 80% for the stable operation of a DCAPT at power of 15–20 kW and nitrogen gas flow rate of 80 SLM with the optimized anode structure. First experimental results of tin, copper, and stainless steel metal powders by the developed HA system with three DCAPTs were analyzed by using the scanning electron microscope (SEM). High quality of spherical shape was observed from the atomized tin, copper, and stainless steel powders. The atomized powders with high size distribution were observed as tin (< 10 μm size), copper (< 50 μm size), and stainless steel (< 10 μm size). Through the plasma–gas hybrid atomizing process, a metal powder having a smaller size than that of the conventional gas atomizing was obtained.