Synthesis of ZrB2 powders by molten-salt participating silicothermic reduction

A novel molten-salt silicothermic reduction method was developed to prepare ZrB2 powders from raw materials of ZrO2, Na2B4O7 and silicon powders with the assistance of sodium orthosilicate in the reaction system. The influences of reaction temperature and quantity of silicon on the phase composition and morphology of final products were investigated. The results showed that the silicothermic reduction reaction for synthesizing ZrB2 was initiated at the temperature as low as 800 °C, and the reaction completed at 1200 °C for 3 h. Only ZrB2 was detected by X-ray diffractormeter in the final products prepared at only 1000 °C for 3 h with addition of excessive 20 wt% Si powders in the reaction system. Moreover, the sheet-like ZrB2 particles were observed by SEM and TEM, which were homogeneously distributed at the samples. •ZrB2 powders were prepared by a novel silicothermic reduction process.•Na4SiO4 can improve the thermodynamic and kinetic conditions of the reaction.•The unique by-product of the reaction is water-soluble and recyclable.