Ultrafine Molybdenum Nitride Powder Prepared by High-energy Mechanochemistry Method

Using the high-energy mechanochemistry ball mill of self-designing,the ultramicro molybdenum nitride powder was prepared through the reaction of molybdenum and ammonia at room temperature.The ratio of grinding media to material was 8:1.After 30 hours of milling,the average particle size was within 100 nm.The chemisorption of ammonia onto the fresh molybdenum surfaces created by milling was the dominated processes govering solid-gas reaction.While the energy input due to introduction of high density ofgrain-boundaries and lattice defects offered the activation energy for the transition from Mo-N chemisorption to molybdenum nitride.The rotational speed of milling plays a critical role in the reaction speed of mechanochemistry process.