【作者】 许并社； 贾虎生； 市野赖英喜；

【Author】 Xu Bingshe Jia Husheng H. I. Ichinose(College of Materials Science and Engineering, Taiyuan University of Technology , Taiyuan, 030024)(The University of Tokyo, Japan)

【机构】 太原理工大学材料科学与工程学院； 东京大学工学部材料系；

【摘要】 在高分辨透射电子显微镜温台上,动态研究了Al、Au、Pt等面心立方金属纳米粒子在电子束辐照下发生的迁移、转动、接合等行为。结果表明相邻的金属纳米粒子相互接触形成金属,金属粒子结合和粒子的团聚,形成了∑3到∑17b的重位点阵界面结构。主要是∑3。在迁移和接合过程中,共格界面和孪晶界面连续移向纳米粒子的表面,最后,这些界面消失,形成一个大的粒子,这些粒子及其团聚体进一步转动。认为纳米粒子的接合机制为表面扩散、体扩散或晶界扩散与粘性流动的复合机制,接合的驱动力为纳米粒子的表面能,它是通过高能电子来传递的,电子束辐照热能不是Al、Au、Pt等纳米粒子移动和接合的主要控制因素。接合的动力学模型为log(r/R)=0.3logf。更多还原

【Abstract】 Behaviors such as migration, rotation, revolution, and bonding of Al, Au, and Pt fcc structured nanoparticles under electron beam irradiation have been investigated by a HRTEM on room temperature stage. It is clear that adjacent metal nanoparticles came into contact and formed a metal/metal particle bond and an aggregation of the particles. The structure of the coincidence site lattice ranged from ∑3 to ∑17b, and ∑3 coincidence site boundaries were preferentially formed. During the migration and bonding processes, the coherent interfaces and twin boundaries continued to move toward the nanoparticle surface. Finally, these boundaries disappeared and produced a large particle, a single crystal or an aggregation of particles on further irradiation. The bonding mechanism, which is considered to be multiple mechanism, is composed of surface diffusion, volume diffusion, or grain boundary diffusion and viscous flow. The driving force of bonding is the nanoparticle surface energy, and it is transferred from a high-energy electron. The bonding growth kinetic model log(r/R) = 0.31og(t) has been suggested. It is also clear that heating effect induced by electron irradiation is not a major controlling factor in the nanoparticle movement and bonding processes.更多还原