硝酸银溶液性质对超细银粉形貌与粒径的影响  

Effect of AgNO_3 solution property on morphology and grain size of ultrafine silver powder

作　　者：郭学益[1] 焦翠燕[1] 邓多[1] 田庆华[1] 易宇[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《粉末冶金材料科学与工程》2013年第6期912-919,共8页Materials Science and Engineering of Powder Metallurgy

基　　金：湖南有色基金资助项目(Z2011-01-001)

摘　　要：以AgNO3为原料,抗坏血酸为还原剂,采用快速加料的方式制备高分散性超细银粉,用扫描电镜、ζ电位分析仪、紫外–可见光谱分析仪等对银粉进行表征,研究硝酸银溶液性质如硝酸银溶液浓度c(AgNO3)、初始pH值,以及表面活性剂的加入对超细银粉形貌与粒径的影响。结果表明,当c(AgNO3)>0.30 mol/L时,银粉表面粗糙、形貌变得不规则且分散性变差。银粉粒度随硝酸银溶液pH值增大而减小,但pH增大到7.0时银粉团聚现象较严重。抗坏血酸分子在还原过程中具有自分散作用,在c(AgNO3)为0.2 mol/L、初始pH=5.0的条件下,不添加任何表面活性剂即可获得分散性好、表面光滑、形貌规则的球形银粉。在AgNO3溶液中加入分散剂PVP可适当减小银粉粒径,而加入丁二酸、吐温80、PEG、PAA和明胶等分散剂对银粉形貌的改善不大。The dispersive ultrafine silver particles were prepared by the reduction of AgNO3 with ascorbic acid as reducer. The properties of the ultrafine silver powders were characterized by scanning electron microscope （SEM）, ζ potential analyzer and ultraviolet-visible absorption spectrum analyzer （UV-VIS）. The effects of concentration, the initial pH value and the addition of the surfactant on the morphology and size of the silver particles were investigated. The results show that, when c （AgNO3）〉0.30 mol/L, the prepared silver powders show rough surface, irregular morphology and worse dispersity. The particle size of silver powder decreases with increasing initial AgNO3 pH value, however, when the initial AgNO3 pH value is 7, the silver powder aggregate severely. The dispersive spherical silver particles with smooth surface can be prepared with the initial AgNO3 pH value of 5.0, concentration of less than 0.2 mol/L by the rapid addition of ascorbic acid without the addition of surfactant. It is deduced that the ascorbic acid plays the self-dispersive role in the reduction process. The size of silver particle can be decreased properly by adding dispersant PVP in AgNO3 solution, whereas, adding dispersant of butanediodic acid, polysorbate 80, PEG, PAA or isinglass has little improvement on the morphology of silver powder.

关 键 词：硝酸银浓度 初始PH值 表面活性剂 超细银粉 抗坏血酸 

分 类 号：TF123.72[冶金工程—粉末冶金]