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研究了以抗坏血酸为还原剂制备球形银粉的工艺过程及球形银粉的形成和长大机制.发现混合方式和速度对银粉的尺寸和形貌影响很大.将抗坏血酸以倾倒方式加入硝酸银溶液中,有利于获得球形的银粉.体系的pH值对银粉的形状影响显著,pH值过小(<1)时,抗环血酸的还原能力较弱,获得片状或枝晶状银粉.pH值过大(>8),远离等电点,颗粒之间排斥力大,颗粒尺寸细小.pH值在4左右时,制得的银粉颗粒呈球型,表面光滑,分散性好,平均粒径为1μm左右,松装密度为2.1 g/cm3,振实密度为4.3 g/cm3,收率为99.49%.
The process of preparing spherical silver powder with ascorbic acid as reductant and the formation and growth mechanism of spherical silver powder were studied.The results show that the mixing method and speed have a great influence on the size and morphology of silver powder.Ascorbic acid is poured into silver nitrate solution by pouring, Is conducive to obtain a spherical silver powder.The pH value of the system significant impact on the shape of the silver powder, pH value is too small (<1), the ability of reducing ascorbic acid to obtain flaky or dendritic silver powder. Large (> 8), away from the isoelectric point, large repulsion between particles, particle size small.pH value of about 4, the silver powder particles were spherical, smooth surface, good dispersion, the average particle size of 1μm , The bulk density of 2.1 g / cm3, tap density of 4.3 g / cm3, the yield was 99.49%.