Nanocrystalline magnesium nitride (Mg3N2) powder was synthesized from bulk magnesium by thermal plasma at atmospheric pressure. Magnesium vapor was generated through heating the bulk magnesium by DC plasma jet and reacted with ammonia gas. Injecting position and flow rates of ammonia gas were controlled to investigate an ideal condition for Mg3N2 synthesis. The synthesized Mg3N2 was cooled and collected on the chamber wall. Characteristics of the synthesized powders for each experimental condition were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and thermogravity analysis (TGA). In absence of NH3, magnesium metal powder was formed. The synthesis with NH3 injection in low temperature region resulted in a formation of crystalline magnesium nitride with trigonal morphology, whereas the mixture of magnesium metal and amorphous Mg3N2 was formedwhen NH3 was injected in high temperature region. Also, vaporization process of magnesium was discussed. (C) 2010 Elsevier B.V. All rights reserved.