The generation and reduction reaction of magnesium plasma were studied using a cylindrical transverse magnetic-mode applicator in magnetic and electric field modes. By heating Mg powder using the magnetic field mode, plasma was generated with the evaporation of Mg and stably sustained. When the Mg plasma sample was introduced into the reaction zone and exposed to microwave and lamp heating, a reduction reaction of scandium oxide also occurred. The results of this study provide prospects for the development of a larger microwave refining system.

Both Cr2O3 and NiO absorb 28 GHz milli-meter-wave energy well and this strong coupling with millimeter-waves can be used to promote a chemical reaction with La2O3 to form perovskite-type LaCrO3 or LaNiO3 ceramics. In La2O3-Cr2O3 system, the reaction proceeded rapidly and single phase LaCrO3 could be synthesized within 15 min even at lower temperature (400) as compared to conventional synthesis (T > 800). In the case of LaNiO3, the reaction proceeded rapidly in the early stage of heating (t < 15 min), but not completed even after prolonged millimeter-wave irradiation. The results suggest an importance of millimeter-wave penetration depth, especially for processing of conductive materials.