阳极弧等离子体制备镍纳米粉的机理研究

Study on the Growth Mechanism of Ni Nanopowders Prepared by Anodic Arc Plasma

摘要:

根据会属结晶的热力学和动力学理论，对采用阳极弧放电等离子体方法制备金属纳米粉的生长过程建立了一个近似的理论模型。研究了等离子体的产生、金属的蒸发、晶核的形成和生长机理。对影响纳米粉性能的各种工艺参数进行了理论分析。并利用X射线衍射（XRD）、透射电子显微镜（TEM）和相应选区电子衍射（ED）对样品的晶体结构、形貌、粒度及其分布进行表征。结果表明：采用阳极弧等离子体法制备的球形镍纳米粒予纯度高，晶格结构与相应的块体物质相同，为fcc结构的晶态，平均粒度为16nm，粒度范围分布在10nm～40nm。电源功率、电弧电流、气体压力及冷却温度是影响晶核的形成和生长的主要因素。通过适当调整各项工艺参数，可有效地控制粒子的粒度。

Abstract:

Based on thermodynamics and kinetics theory, a theoretical model to illuminate the process for preparing metal nanopowders by anodic arc discharging plasma method was set up, and the origin of plasma, metallic evaporation, the mechanism of particle nucleation and growth were investigated. The influences of various technology parameters on the properties of nanopowders by Anodic Arc Plasma were also discussed. In addition, the samples prepared by this method were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the corresponding electron diffraction (ED) to determine the crystal structure, morphology, particle size and particle size distribution. The experimental results show that the crystal structure of the nanopowder sample is the same as the bulk material, being fcc structure, with an average size about 16 nm, distribution ranging from 10 nm to 40 nm. The technology parameters (such as the power supply, the pressure of gas, the arc current intensity, water-cooling condition, etc.) have great effect on the particle nucleation and growth, the particle size can be effectively controlled by varying the technological parameters.