工艺参数对液相还原法制备超细银粉形貌特征的影响

摘要

研究硝酸银浓度、抗坏血酸浓度、反应体系温度及pH值、添加剂种类及用量对液相还原法制备超细银粉形貌特征的影响,借助SEM、粒度仪、比表面仪和颗粒图像分析仪对银粉进行表征和分析.结果表明,pH值是同时影响银粉形状、粒度和分散性的显著因素,添加剂用量和抗坏血酸浓度分别是影响银粉形状及分散性的显著因素;随着pH值由2逐渐增大至10,银粉呈现由无规则多面体至棒状、类球形的形状变化,平均粒径逐渐减小;随着添加剂用量增加,银粉呈现由异形至球形、刺球型的形状变化,其用量质量分数为2.5％时颗粒球形度值最大;随着抗坏血酸浓度增加,银粉的分散性逐渐变差,其浓度为0.5 mol/L时分散性最好.%Effect of the concentration of AgNO3 and ascorbic acid,the temperature and pH of reaction system,the type and dosage of addition agent on the morphology of ultrafine silver powders by liquid phase reduction method were explored.Particles were characterized and analyzed with SEM,particle size analyzer,surface area analyzer and particle image analyzer.It shows that pH value is a significant factor affecting the particle size,morphology and dispersion simultaneously,while the dosage of addition agent and ascorbic acid concentration are significant factors affecting particle morphology and dispersion respectively.As the pH value gradually increased from 2 to 10,particles presented shape change by irregular polyhedron,rod-shaped to spherical,and average particle size gradually decrease.As the dosage of addition agent increase,particles present shape change by irregular to spherical,spiky ball,and the sphericity of particles is the greatest when the dosage was 2.5％.With increasing ascorbic acid concentration,the dispersion of particles become worse,and particles are at best dispersion when it is 0.5 mol/L.