【摘要】 采用液相化学还原法,以改性聚乙烯吡咯烷酮为分散稳定剂,用抗坏血酸还原硝酸银得到银溶胶,将银溶胶经离心分离、洗涤和真空干燥处理,得到规则球形纳米银粉。用动态光散射法激光粒度仪考察反应温度和溶液的pH值对纳米银粉粒度的影响。用扫描电镜(SEM)观察纳米银粉的形貌。用X射线衍射(XRD)表征纳米银粉的晶体结构。研究结果表明,反应温度为40℃、w(PVP):w(AgNO3)=0.8、AgNO3浓度为0.24mol/L、抗坏血酸溶液pH值=10,可得到具有至少3级循环套嵌自相似结构的规则球形纳米银粉;纳米银粉聚集体纯净无杂质,粒径在500～1000nm之间;粉体一次颗粒粒径为9～20nm。更多还原

【Abstract】 Silver sols were prepared from silver nitrate by chemical reduction in liquid phase,with ascorbic acid as the reducing agent and modified polyvinylpyrrolidone as the protecting agent.A nanometer silver powder with regular spherical shape was got from the sols treated with centrifugal-separating,washing and vacuum-drying.Effects of reaction temperature and solution pH value on particle size of the nano silver were studied using dynamic light scattering laser particle size analyzer.Features of the nano silver were observed by scanning electron microscopy,and crystal structure of the nano silver was characterized through X-ray diffraction.The results show that a nano silver powder with regular spherical shape and self-similar structure embedded in three-grade cycle at least can be obtained under the reaction conditions of 40 ℃,PVP/AgNO3=0.8,c(AgNO3)=0.24 mol/L,and pH value of ascorbic acid solution at 10.The nano-silver powder aggregate is pure and inclusion free,particle size of which is between 500 nm and 1 000 nm,and of the initially formed particle is 9～20 nm.更多还原