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1、第18卷第6期WL】8No62013年12月Dec. 2013粉末冶金材料科学与工程Materials Science and Engineering of Powder Metallurg*以丙三醇为还原剂的沉淀转化法制备超细银粉11!陈建波，李启厚，李玉虎，刘智勇，刘志宏（中南大学冶金与环境学院,长沙410083）摘 要：在水PVP体系中，以氣化银(Ag2O)为前驱体、丙三醇为还原剤，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，研究氣化银转化生成银粉的机理及银粉的形貌与 粒度控制规律。结果衣明：银粉形成机理为Ag2O溶解和Ag还原再结晶
2、，为确保Ag?O完全还原，Ag2。/丙三醇 靡尔比应小于或等于3:1；添加氨有利于制备粒度均匀、无团聚的类球形银粉，丙二醇浓度对银粉粒度的影响较 大。在温度为80 r. A&o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 moVL,且 其加料速度为6 mL/min, PVP添加量为Ag2O质量的】的条件下，可以制备出平均粒度为0.52 gm和粒度分布 范围较窄的超细银粉。关键词：氧化银；丙三醇；沉淀转化法：超细银粉中图分类号：TF123.72文献标识码：A文章编号:1673-0224(2013)6.874-08Preparation of ultra-f
3、ine silver powders byprecipitation-transformation method using glycerol as reductantCHEN Jian-bo, LI Qi-hou, LI Yu-hu, LIU Zhi-yong, LIU Zhi-hong(School of Metallurgical and Environment, Central South University, Changsha 410083, China)Abstract: The preparation of ultra-fine silver powders was inves
4、tigated by precipitation-transformation method using Ag2O as precursor and glycerol as reductant in H2O-PVP system. The samples were characicrized by XRD. SEM and laser size analyzer; the formation mechanism and the mechanism of controlling morphology and size of silver powders were studied experime
5、ntally. The results show that silver powders arc formed by crystallization of Ag atom obtained from the reduction of Ag ions, which come from the dissolution of Ag?。. 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 pr
6、eparation. 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 moiar ratio of 2:1, glyc
7、erol 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 pm and narrow size distribution can be obtained.Key words: silver oxide; glycerol; solid phase transformation; ultra-fine silver powder银因其导电性好、金贵金属
8、中价格相对较低而广 泛应用于微电子及光伏产业。银粉为银的主要应用形 式，近年来，随若微电子和光伏产业的高速发展，市 场对高性能银粉的需求日益增大，使得银粉制备技术 成为研究热点【卜2】。银粉种类繁多，性能各界，其制备 方法可分为火法和湿法两大类。火法工艺有喷雾热解 法、微波等离子法等，银粉球形度好、结晶度与振实密度高，但粒度粗且粒径分布较宽。湿法工艺主要 有液相还原法【呦、电解法、微乳液法&9J筹。电解 银粉呈树枝状形貌，比表面积人，粒度分布不均匀。 微乳液法可制备出粒度可控的银粉，但液固分离困难。 液相还原法工艺简单、粉末形貌及粒度调控手段多、 易于产业化，是工业制备银粉的主耍方法。银的标准 电极电势较高（収Ag+/AB= 0.799 1 V）,易于还原，因而基金项目：教am世纪优秀人才资助计划（NCETJIP517；中国博士后科学戏助堆金C012M521544） 收稠日期：2013-01-30：修订日期；2013-04-07通讯作奢：刘，占氐 博士，教授电话：0731-88830478： E-mail:zhliu