液相化学还原法制备形貌粒径可控的超细银粉研究

发布时间：2018-04-22 15:08

  本文选题：液相化学还原法 + 超细银粉　； 参考：《长沙理工大学》2015年硕士论文

【摘要】：为了制备球形高品质超细银粉,本文采用液相化学还原法制备形貌和粒径可控的超细银粉,对原料及工艺进行了研究,主要内容如下:1、比较了不同银源、还原剂、分散剂对超细银粉形貌和粒径的影响。结果表明AgNO3、抗坏血酸和PVP(K30)更适合作原料制备高分散球形超细银粉。2、考察了工艺条件对超细银粉形貌和粒径的影响。结果表明:随着反应体系中PVP加入比例的增加,银粉形貌由不规则形状到花瓣状到球形,粒径逐渐减小;随着体系反应温度的增加银粉颗粒团聚程度增加,粒径增大,形貌基本无变化;随着溶液pH值增大,颗粒团聚程度增加,平均粒径变大;随着AgNO3浓度增加,银颗粒平均粒径变大;较快的滴液速度有利于得到粒径分布范围较窄且分散性良好的均一球形银粉;有机溶剂作为洗涤过滤液有利于提高银粉的分散性。3、结合实验和理论分析研究了影响超细银粉形貌和粒径的控制因素。结果表明银粉成核作用主要影响银粉颗粒的粒径和粒径的分布范围;控制银粉生长过程可在一定程度上实现对银粉形貌和粒径的调控;银原子浓度较快上升时的成核与生长模式有利于得到粒径均一的球形银粉;银颗粒的团聚主要以颗粒“联结”和“架桥”形式出现。4、以硝酸银为原料,采用PVP(K30)为分散剂,抗坏血酸为还原剂,当AgNO3浓度为0.2mol/L,m(PVP)/m(AgNO3)为0.6,pH值为7,反应温度为40℃,滴液速度为5ml/s,分离干燥环境为无水乙醇时,可获得表面光滑、球形度高、粒径分布集中于0.45~1.3μm,平均粒径为0.8μm的高分散超细银粉。本文研究结果将为制备球形、花瓣状和其它复杂形貌的高品质超细微米/亚微米级银粉提供一定的技术支撑和理论指导。
[Abstract]:In order to prepare spherical and high quality ultrafine silver powder, ultrafine silver powder with controllable morphology and particle size was prepared by liquid-phase chemical reduction method. The raw materials and technology were studied. The main contents were as follows: 1. The different silver sources and reductants were compared. Influence of dispersant on morphology and particle size of ultrafine silver powder. The results showed that Agno _ 3, ascorbic acid and PVP _ (K30) were more suitable for the preparation of highly dispersed spherical ultrafine silver powder. The effects of technological conditions on the morphology and particle size of ultrafine silver powder were investigated. The results showed that the morphology of silver powder decreased from irregular shape to petal shape to spherical shape with the increase of the proportion of PVP in the reaction system, and the particle size increased with the increase of reaction temperature, and the agglomeration degree of silver powder increased with the increase of reaction temperature. With the increase of pH value of the solution, the particle agglomeration degree increases, the average particle size becomes larger, and the average particle size increases with the increase of AgNO3 concentration. The higher the droplet velocity is, the more narrow the particle size distribution range is and the better the dispersion is, the uniform spherical silver powder can be obtained. Organic solvent was used as washing and filtering liquid to improve the dispersity of silver powder. Combined with experiments and theoretical analysis, the controlling factors affecting the morphology and particle size of ultrafine silver powder were studied. The results showed that the nucleation of silver powder mainly affected the particle size and distribution range of silver powder, and the control of the growth process of silver powder could realize the regulation of the morphology and particle size of silver powder to a certain extent. The nucleation and growth mode of silver atom concentration increases rapidly in favor of the spherical silver powder with uniform particle size, and the agglomeration of silver particles mainly occurs in the form of particle "bonding" and "bridging", with silver nitrate as the raw material and PVP K30 as dispersant, the agglomeration of silver particles is mainly in the form of "joining" and "bridging". When ascorbic acid was used as reducing agent, when the concentration of AgNO3 was 0.2 mol / L, the pH value of AgNO3 was 0.6 渭 mol / L, the reaction temperature was 40 鈩，

本文编号：1787745