聚焦超声辅助电火花制备多尺度镍粉时超声功率对镍粉粒径的影响  

Effect of Ultrasonic Power on the Particle Size of Multiscale Nickel Powders Produced by the Focused Ultrasound-assisted Electrical Discharge Machining

作　　者：侯启龙 刘一凡 林发明 李翔龙[1] HOU Qilong;LIU Yifan;LIN Faming;LI Xianglong(School of Mechanical Engineering,Sichuan University,Chengdu 610065,China;School of Materials and Energy,University of Electronic Science and Technology,Chengdu 611731,China;School of Mechanical Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]四川大学机械工程学院,成都610065 [2]电子科技大学材料与能源学院,成都611731 [3]西南交通大学机械工程学院,成都610031

出　　处：《材料导报》2020年第16期16114-16118,共5页Materials Reports

基　　金：国家自然科学基金(51275324;51435011);科技部创新方法工作专项:四川省创新方法推广应用示范(20171M010700)。

摘　　要：电火花-超声复合加工技术是一种绿色环保、易于控制的制备微纳米金属粉末的方法。为了研究聚焦超声功率对微纳米金属粉末形貌和粒径分布的影响,本工作通过COMSOL Multiphasic仿真软件模拟超声在工作箱中的声压分布,确定放电位置,并根据仿真结果,采用实验室自制设备以镍棒为电极在纯水中进行实验。实验结束后观察微米尺度与纳米尺度镍粉的形貌,并分析微纳米镍粉的粒径分布。结果表明:聚焦超声的空化和振动效应能有效地破碎固液相中的金属蒸气团簇和金属液滴,便于制备出小尺寸的镍颗粒,并使其均匀地分布在溶液中;声空化产生的冲击波使镍颗粒发生碰撞,大尺寸的镍颗粒在撞击点处产生的高温使镍粉发生烧结,形成金属烧结颈,多个球形颗粒团聚成不规则的大颗粒;小尺寸的镍颗粒由于粒径小,发生碰撞后产生的能量不足以使其团聚。The ultrasonic-assisted electrical discharge is a green,easy and controllable approach to generate micro-nano metallic powders.To investigate the effect of focused ultrasonic power on the morphology and particle size distribution of micro-nano metallic powders,the COMSOL Multiphasic simulation software was applied to simulate the sound pressure distribution of ultrasonic in the working box to determine the discharge position.Then,according to the simulation results,a lab-made equipment was used to carry out the experiments in pure water with nickel bar as electrode.After the experiments,the morphology of micron-scale and nano-scale nickel powders were observed,and the size distributions were analyzed.The results reveal that the cavitation and vibration effects of focused ultrasound can effectively break the metal vapor clusters and droplets in the solid-liquid phase,which helps to decrease the size and obtain the Ni particles colloids with very small size.The shock wave generated by acoustic cavitation makes the nickel particles collide,which results in a high temperature to form a sintering neck between two nickel powders.In addition,spherical particles agglomerate into irregular particles with large size.However,due to the small size effect,the energy generated by the collision is not enough to make the agglomeration phenomenon between small size particles.

关 键 词：电火花-超声复合加工 聚焦超声功率 烧结现象 粒径分布 

分 类 号：TG146[一般工业技术—材料科学与工程]