纳米Ag粉的显微结构和性能表征

Characterization of microstructure and properties of Ag nanoparticles prepared by flow-levitation method

采用自悬浮定向流法制备纳米Ag粉。用透射电镜(TEM)、X射线能量色散谱(EDAX)、X射线衍射(XRD)、紫外-可见光吸收光谱(UV-Vis)和差示扫描量热法(DSC)对纳米微晶形貌、粒度、结构和性能进行研究。结果表明:在He气和Ar气流中制备的纳米Ag粉的平均粒径分别为15 nm和80 nm;颗粒基本为球形,贮存在未密封的广口瓶中1 a后含氧量为1.04%,最大的吸收峰出现在波长为283 nm处,熔化焓为93.55 J/g,熔点为959.70℃,比粗晶银的熔点(961.93℃)低2.23℃。

Ag nanoparticles were prepared by flow-levitation method. The morphologies, granularities, structure and properties of particles were investigated by means of transmission electron microscopy（TEM）, energy dispersive analysis of X-ray（EDAX）, X-ray diffraction（XRD） analysis, UV-Visible absorption spectroscopy and thermal analysis （DSC） techniques. The results show that mean granularity of the almost spheric Ag nanoparticles are 15 nm and 80 nm in 100% He and 100% Ar gas flow, respectively; When Ag nanoparticles are kept in unsealed glass bottle for one year in air, the oxygen of Ag nanoparticles prepared in Ar is （mass fraction） 1.04%, which shows Ag nanoparticles possess inoxidizability. The maximum specific absorption appears at wavelength of 283 nm, which is different from other Ag nanoparticles, and its melting point and fusion enthalpy are 959.7 ℃ （which is 2.23 ℃ lower than that of coarse grained Ag） and 93.55 J/g, respectively.