沉淀转化法制备超细银粉试验研究

Experimental Study on the Preparation of Superfine Silver Powder by Precipitation-transformation Method

以Ag2O为前驱体,葡萄糖为还原剂,聚乙烯吡咯烷酮(PVP)等为分散剂,对沉淀转化法制备超细银粉进行了研究。试验考察了反应体系pH值、分散剂、葡萄糖浓度及反应温度对银粉形貌与粒度的影响。结果表明,随着pH值的增加,银粉粒径呈先减小后增大的趋势,偏酸性体系中银粉粒径分布较宽,而偏碱性体系中颗粒团聚明显且其粒径分布宽;以PVP为分散剂可制备出分散性良好的类球形超细银粉;提高葡萄糖浓度,银粉粒径减小;温度升高银粉粒径增大且团聚严重。在100mL高纯水中加入8 g Ag2O和0.08 g PVP,控制反应温度为30℃,接着并流加入0.35 mol/L葡萄糖溶液和0.18 mol/L氨水溶液,控制体系pH值为8的条件下,可制备出粒径在1μm左右且分散良好的类球形超细银粉,其粒度可调。

An experimental study on the preparation of superfine silver powder by precipitation-transformation method was carried out with Ag20 as precursor, glucose as reducing agent, and PVP or other surfactants as dispersant. The effects of pH, dispersants, temperature, and concentrations of glucose on the morphology and size of the silver powder were investigated. The results show that particle size decreased at first and then increased with the rising of pH, acidic condition resulted in a wide size distribution, and basic condition lead to obvious aggregation and a wide size distribution of the silver particles;well dispersed spherical-like superfine silver powder could be obtained with PVP as dispersant; particle size decreased with the increasing concentrations of glucose; particles became larger and more agglomerated under the rising of temperature. Spherical-like superfine silver powder with good dispersity and particle size around 1 μm was prepared by a controlled double-jet process（ CDJP） adding glucose（0.35 mol/L）and ammonium solutions（0.18 mol/L）into 100 mL ultrapure water containing 8 g Ag20 and 0.08 g PVP with reaction temperature maintained at 30 ~C and pH at 8.0,and the particle size was under eontrol.