Optimization of Plasma Parameters for Improved Spheroidization of Alumina Using a New RF-ICP Torch

This study explores the spheroidization of alumina (Al₂O₃) powder using a novel Radio Frequency Inductively Coupled Plasma (RF-ICP) torch, combining computational simulations with experimental techniques. A 2D axisymmetric model was developed in Ansys Fluent to simulate particle injection, heat transfer, and calculate the spheroidization ratios of the powders. Experimentally, crushed alumina powder with an average particle size of 20 µm was treated in an RF-ICP setup. Key parameters, including input power, carrier gas flow rate, and powder feed rate were varied to evaluate their influence on the spheroidization process. Both argon and nitrogen were used as a carrier gas. SEM, XRD, and laser particle size analysis were employed to examine the powders' morphology, phase composition, and size distribution before and after plasma treatment. The results showed that higher input power, optimal carrier gas flow rates, and powder feed rates significantly improved the spheroidization ratio by enhancing heat transfer and particle melting. Nitrogen, with its higher thermal conductivity, was found to be more effective than argon as a carrier gas, yielding higher spheroidization ratios. These findings provide valuable insights into the optimization of plasma spheroidization processes for producing high-quality spherical powders for advanced manufacturing applications.