Electrometallurgy Today, 2026, №01

2026 №01 (02)

DOI of Article 10.37434/sem2026.01.03

2026 №01 (04)

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"Suchasna Elektrometallurgiya" (Electrometallurgy Today), 2026, #1, 17-26 pages

A new approach to spheroidization of iron powders using a reverse polarity DC plasma torch with an external remote electrode

V.M. Korzhyk , O.S. Tereshchenko , D.V. Strogonov , V.S. Petruk , O.F. Tyshchenko , V.E. Yarosh

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: vn@paton.kiev.ua

Abstract
The paper presents and experimentally substantiates a new approach to plasma spheroidization of irregularly shaped powders, which is critically important for the production of raw materials for additive technologies (3D metal printing). It is proposed to use a reverse polarity DC plasma torch with an external remote electrode, the position of which can be adjusted during the arc discharge. It was found that this approach allows raising the operating voltage and the total arc power by 3‒4 times (up to 100 kW and more) and significantly increasing the volume and length of the plasma jet (up to 100…180 mm), which markedly improves the processing efficiency. The feasibility and effectiveness of the method were confirmed using the example of irregularly shaped PZhR iron powder. After plasma treatment, about 95 % of the particles were melted and spheroidized. This led to a significant improvement in technological properties: the sphericity coefficient increased from 0.18…0.20 to 0.86…0.89; the powder flowability increased by 25 % (for the ‒63 μm fraction) and by 75 % (for the 63…160 μm fraction); the bulk density increased by 20…39 %. The results demonstrate that the proposed design of a plasma torch with a controlled arc length is a promising alternative to existing radio frequency and arc systems, and it can be effectively adapted in the future for spheroidization of a wide range of refractory and ceramic powders. 27 Ref., 1 Tabl., 8 Fig.
Keywords: plasma spheroidization, reverse polarity plasma torch, irregularly shaped powders, additive technologies, flowability, sphericity coefficient, powders

Received: 05.12.2025
Received in revised form: 06.02.2026
Accepted: 31.03.2026
Posted online: 14.04.2026

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Suggested Citation

V.M. Korzhyk, O.S. Tereshchenko, D.V. Strogonov, V.S. Petruk, O.F. Tyshchenko, V.E. Yarosh (2026) A new approach to spheroidization of iron powders using a reverse polarity DC plasma torch with an external remote electrode. Electrometallurgy Today, 01, 17-26. https://doi.org/10.37434/sem2026.01.03