Comparative Study on the Differences of Argon and Nitrogen in the Inert Gas Atomization for Metal Powder Production

Inert gas atomization utilizes the kinetic energy of a highly underexpanded (p0/pAmb = 10 - 60) supersonic gas jet to disintegrate a stream of molten metal to produce chemically pure and spherically shaped metal powders (1-150 μm). Metal powders are used as feedstock in manufacturing industries like metal additive manufacturing (AM), metal injection molding (MIM), or thermal spraying, which all have strict requirements for chemical pure powders in common, necessitating the use of inert gases in gas atomization considering the reactivity of molten metals with oxygen. The gas atomization process faces challenges primarily in enhancing yield and, therefore, achieving cost-effective production, among others, caused by a lack of full understanding of the fluid mechanic mechanisms involved. Complexity for experimental investigations arises from short time scales due to high velocities and significant differences in the involved length scales, e.g., apparatus size vs. particle size. Recent insights into the multiphase interaction in the nozzle nearfield were achieved by APELL ET AL., who published promising experimental results with an air gas jet and water used as a substitute for inert gases and molten metal, respectively [1]. This study presents initial pure gas results obtained through high-speed Schlieren imaging and high-frequency pressure measurements. These results indicate variations in the shock structure of gas jets based on the type of gases used. Building on these introductory findings, the experiments conducted by APELL ET AL. were validated using inert gases, specifically argon and nitrogen, as atomization gases. Ongoing experimental investigations involve multiphase experiments with water and inert gases to further validate and extend recent insights into multiphase interaction in gas atomization. The combination of the pure gas results and the multiphase experiment will enhance the understanding and control of fluid mechanic mechanisms and enable improved industrial processes.     «

Inert gas atomization utilizes the kinetic energy of a highly underexpanded (p0/pAmb = 10 - 60) supersonic gas jet to disintegrate a stream of molten metal to produce chemically pure and spherically shaped metal powders (1-150 μm). Metal powders are used as feedstock in manufacturing industries like metal additive manufacturing (AM), metal injection molding (MIM), or thermal spraying, which all have strict requirements for chemical pure powders in common, necessitating the use of inert gases...     »