摘要
在水-PVP体系中,以氧化银(Ag2O)为前驱体、丙三醇为还原剂,采用沉淀转化法制备超细银粉。借助扫描电镜(SEM)、X射线衍射(XRD)、激光粒度分析等表征手段,研究氧化银转化生成银粉的机理及银粉的形貌与粒度控制规律。结果表明:银粉形成机理为Ag2O溶解和Ag+还原再结晶,为确保Ag2O完全还原,Ag2O/丙三醇摩尔比应小于或等于3:1;添加氨有利于制备粒度均匀、无团聚的类球形银粉,丙三醇浓度对银粉粒度的影响较大。在温度为80℃,Ag2O与丙三醇摩尔比为2:1,采用NH3·H2O为pH值调节剂,丙三醇浓度为2.4 mol/L,且其加料速度为6 mL/min,PVP添加量为Ag2O质量的1%的条件下,可以制备出平均粒度为0.52μm和粒度分布范围较窄的超细银粉。
The preparation of ultra-fine silver powders was investigated by precipitation-transformation method using Ag2O as precursor and glycerol as reductant in H2O-PVP system. The samples were characterized by XRD, SEM and laser size analyzer;the formation mechanism and the mechanism of controlling morphology and size of silver powders were studied experimentally. The results show that silver powders are formed by crystallization of Ag atom obtained from the reduction of Ag＋ ions, which come from the dissolution of Ag2O. The molar ratios of Ag2O/glycerol should be obtained at less or equal to 3：1 in order to reduce Ag2O into silver completely in the preparation. Adding ammonia as pH modifier is beneficial to prepare silver powders with uniform morphology and size, and glycerol concentration affects the sizes of silver powders seriously. Adding ammonia as pH modifier, under the condition of temperature of 80 ℃, Ag2O/glycerol molar ratio of 2：1, glycerol concentration of 2.4 mol/L, reductant feeding rate of 6 mL/min and adding PVP of 1%Ag2O mass, the silver powders with a mean particle size of 0.52？m and narrow size distribution can be obtained.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2013年第6期874-881,共8页
Materials Science and Engineering of Powder Metallurgy
基金
教育部新世纪优秀人才资助计划(NCET-11-0517)
中国博士后科学资助基金(2012M521544)
关键词
氧化银
丙三醇
沉淀转化法
超细银粉
silver oxide
glycerol
solid phase transformation
ultra-fine silver powder
