Preparation Of Flake Silver Powder By Photo - Induced Reduction

In this paper, light-induced chemical reduction method, the choice of ascorbic acid, sodium citrate as a reducing agent to PVP-PVA.Mixed surface protective agent, using a new, simple and efficient test system designed and assembled, prepared sheet, distributed evenly, good crystalline properties of nanoscale silver. By studying the reaction temperature, reactant concentration, reducing the molar ratio of silver nitrate, surface protection and other process parameters on the dosage of the average particle size and morphology of nano-silver, determined the light-induced reduction of silver flake prepared by process conditions:reaction temperature55℃,50w high pressure mercury lamp (wavelength352nm) irradiation45h, AgNO3concentration of0.2mol/L.Since different light-induced reduction of reducing the sensitivity of the reducing agent thus screened and found to glucose, sodium citrate, ethanol, and ascorbic acid as reducing agent, can better adapt the lighting conditions, the silver nitrate is more fully reduction. Respectively, glucose and sodium citrate, ascorbic acid as a reducing agent in ethanol and light-induced method to study the reaction temperature, the concentration of AgN03solution, reducing the concentration, exposure time, light intensity on the morphology size.Through the analysis of test results showed that:the reaction temperature, AgNO3solution concentration, reducing the concentration of the reducing agent and the type and amount of AgNO3molar ratio and the presence of a surface protective agent a greater impact on the silver particle size and morphology, nano silver particle size as the reaction temperature tends to decrease; with AgNO3solution concentration increases, the resulting change in particle size is fairly obvious; with increasing concentration of the reducing agent, silver particle size increases; with reductant and increase the molar ratio of silver nitrate, silver particle size in the decreasing tendency; considering the purity of the final product, determine the optimum dosage for the surface protective agent is4percent. Light intensity has a significant influence on the silver flake prepared, in particular on the particle size and morphology, the light irradiation intensity of the high temperature of the reaction solution will rapidly increase and ignore the silver flake in the form of nano-control appearance and particle size. X-ray diffraction patterns indicate that the final product is a face-centered cubic elemental silver, and the product crystallized good performance.