Synthesis of nanocrystalline magnesium nitride (Mg_3N_2) powder using thermal plasma

摘要

Nanocrystalline magnesium nitride (Mg_3N_2) 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 Mg_3N_2 synthesis. The synthesized Mg_3N_2 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 ther-mogravity analysis (TGA). In absence of NH_3, 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 Mg_3N_2 was formed when NH3 was injected in high temperature region. Also, vaporization process of magnesium was discussed.