微观浓度场对银生长形貌的调控作用  

Role of micro-concentration field on morphology of silver particles

作　　者：胥永辉 陈道梁 孙东科[3] 李金兵[4] 韩永生[1,2] XU Yonghui;CHEN Daoliang;SUN Dongke;LI Jinbing;HAN Yongsheng(State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;School of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;School of Mechanical Engineering,Southeast University,Nanjing 211189,Jiangsu,China;Yanshan Branch of Sinopec Beijing Research Institute of Chemical Industry,Beijing 102500,China)

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]中国科学院大学化工学院,北京100049 [3]东南大学机械工程学院,江苏南京211189 [4]中国石化北京北化院燕山分院,北京102500

出　　处：《化工学报》2020年第S02期281-288,共8页CIESC Journal

基　　金：国家自然科学基金项目(91934302,21978298,U1862117)。

摘　　要：利用原位光学显微镜和计算模拟技术研究了材料生长界面微观浓度场对材料结构演化的影响。在电沉积法制备银颗粒中,通过调控电位在电解液中生成氧化银胶体粒子。在外加电场作用下胶体粒子在溶液中运动,进而带动溶质的定向迁移;通过外加电场控制胶体粒子迁移速度,调控生长界面溶质浓度分布。随胶体粒子迁移速度增加,界面传质增强,颗粒生长前沿扩散层变薄,浓度梯度变大,银颗粒形貌由球状纳米晶变为对称枝晶结构,生长速度由10μm2/s增大到60μm2/s。最后结合格子Boltzmann模拟结果,验证了界面浓度场对银颗粒形貌演化的调控作用。To reveal the role of interface micro-concentration distribution on the evolution of materials structure,silver crystallization was investigated by the in-situ optical microscopy and lattice Boltzmann simulations.Silver particles were synthesized by electrodeposition,in which silver oxide colloid particles were generated as the byproducts.The migration velocity of colloid particles in the electrolyte was regulated by the electric field.With the increase of migration velocity of colloid particle,mass transfer increased,the diffusion layer in the front of the growth became thinner,and the concentration gradient became sharper.As a result,the morphology of silver particles changed from spherical nanocrystals to symmetrical dendrites,and the growth rate increased from 10μm2/s to 60μm2/s simultaneously.Finally,it was proposed that the micro-concentration field in the diffusion layer is the main mechanism dominating the evolution of particle morphology,which was verified by the lattice Boltzmann simulation of convection diffusion and phase transition.

关 键 词：微观浓度场 银颗粒 原位研究 动态生长 形貌演化 浓度梯度 

分 类 号：TQ151.5[化学工程—电化学工业]