Nb和N_2在球磨过程中的固-气反应

Solid-Gas Reaction of Nb and N_2 During Ball Milling Priocedure

利用改装后可充一定压力气体的球磨罐，装入一定量的高纯金属，经抽真空后充入一定压力的氮气，在室温下进行球磨产生固－气反应制备出金属氢化物的超细微粒．以金属铌为例，用XRD和TEM分别对生成物的晶粒尺度和相结构进行了分析测量．从热力学讨论了金属氮化的形成机制，在固－气反应中氮气分子在金属清洁表面的化学吸附起着重要作用．球磨过程中产生的大量缺陷对金属－氮气的反应有重要影响．

Using a specifically designed ball mill equipment, solid-gas reaction of niobiun with molecular nitrogen were driven and nanocrystallites of metal nitrides of NbN were synthesized by simple milling of pure niobium powders in molecular nitrogen atmosphere at room temperature.The structure and the grain size formed with different milling materials have been investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The chemisorption of nitrogen onto clean metal surfaces is believed to play a critical role in such a solid-gas reaction. The chemisorption and subsequent formation of metal-nitrides are discussed according to thermokinetics. Attention is pained to the effect of defects generated during milling procedure on metal-N2 reaction.