Molten-salt nitridation synthesis of cubic ZrN nanopowders at low temperature via magnesium thermal reduction

Abstract

ZrN nanopowders were obtained by using ZrO2 and Mg as the main raw materials in a molten salt environment and a high-purity nitrogen atmosphere. The effects of ZrO2 / Mg mole ratio, nitriding temperature, and holding time on the synthesis of ZrN were investigated. ZrN was formed at 700 °C for 3 h. When the nitriding temperature increased to 1000 °C, pure phase ZrN was formed. The specific surface area of ZrN was 20.92 m2/g. When the temperature rose to 1100 °C, the resulting ZrN particles were finer; the average size of ZrN decreased from 71.60 to 49.65 nm. Further, an excessively long holding time led to evaporation of the molten salt, ZrO2, which was not fully nitrided. Finally, a possible formation mechanism of ZrN is proposed.