通過原位電子束定域輻照研究PbO包覆Pb核－殼納米粒子的晶化、凝固與納米流體過程

In this paper, the crystal growth, phase transition and related thermodynamics and kinetics at the nanoscale is investigated based on in-situ heating and eroding of Pb/PbO core-shell nanoparticles with a focused electron beam in a transmission electron microscope (TEM). The crystallization of the amorphous lead nano-core induced by the heating effect under the electron beam irradiation was observed. The distinguishable boundary between the Pb nanocrystal and the amorphous PbO shell produces clear contrast in TEM image, which can be used to measure the thickness of the PbO shell. By tuning the intensity of the focused electron beam irradiation, melting, splitting, solidification as well as recrystallization of the PbO-coated Pb nanoparticles was induced and observed on real time. The electron nano-beam was also used to selectively erode the PbO nano-shell and melt the Pb nano-core, which generates nanoscale metal fluid directionally effusing through the cracked oxide shell. The stability of the oxide nanos hell was also analyzed. And the potential application the above processes in nanotechnology is also discussed briefly.