银氨体系抗坏血酸还原制备超细球形银粉  

Preparation of ultra-fine spherical silver powder with reduction of tollens reagent by ascorbic acid

作　　者：田庆华[1] 邓多[1] 焦翠燕[1] 郭学益[1] 

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2015年第12期4404-4410,共7页Journal of Central South University:Science and Technology

基　　金：国家国际科技合作专项项目(2014DFA90520);广东省产学研项目(2013A100003)~~

摘　　要：以银氨为原料,抗坏血酸为还原剂制备超细球形银粉。考察加料速度、溶液初始pH、反应温度、AgNO_3溶液浓度等工艺参数对银粉形貌、粒径的影响,对银粉进行扫描电镜、X线衍射和ζ电位分析等表征,研究银粉的分散和生长机理。研究结果表明:采用快速加料法,在硝酸银溶液浓度不大于0.5 mol/L,反应温度低于60℃,银氨溶液初始pH为12.0,不使用分散剂的条件下,可制备出分散性好,形貌规则的球形银粉。银粒子在该体系中具有自分散作用,银粉的生长符合二段生长模型。The dispersive ultra-fine spherical silver powder was prepared by chemical reduction with tollens reagent as feed solution and ascorbic acid as reductant. The effects of feeding speed, initial pH value, reaction temperature and concentration of AgNO_3 on the morphology and particle size of silver powder were investigated. The scanning electron microscope, the X-ray diffraction and the ζ potential analyzer were used for the characterization of the product. Besides, the dispersion and growth mechanism of silver powder was discussed. The results show that the optimal dispersive spherical silver powder is prepared under the condition that the concentration of AgNO_3 solution is no more than 0.5 mol/L, the reaction temperature is lower than 60 ℃, and the initial p H value is 12.0 by the rapid addition of ascorbic acid without using any dispersant. The silver particles have self-dispersive function, while the growth of silver powder follows the two-stage growth model.

关 键 词：超细球形银粉 加料速度 分散机理 生长机理 

分 类 号：TF123.72[冶金工程—粉末冶金]