RF thermal plasma-assisted metallothermic synthesis of ultrafine ZrB2 powders

Ultrafine ZrB2 powders were synthesized in radio-frequency atmospheric-pressure thermal plasma using ZrCl4, B, and Mg as raw materials. The metallothermic reaction was ignited by the high temperature flame when the mixed precursors were carried into thermal plasma, and then propagated with the exothermic reaction enthalpies and the external energy supplied by plasma flame. Both thermodynamic analysis and experiments were conducted. The as-prepared samples were characterized by X-ray Diffraction, Transmission Electron Microscopy, and particle size analyzer. Results showed that the obtained ZrB2 powders had particle size of about 100 nm and surface area of 30.75 m2/g. The laboratory production rate was about 300 g/h.