| Electronic conductive paste is a collection of electronic, chemical, metallurgical high-tech value-added products. With the rapid development of electronic information industry, the production of Electronic conductive paste has also made great progress. As the crominiaturization and flexibility of electronic components, the traditional micron electrocondution slurry can not meet the requirements of low-temperature sintering and multi-layer wiring. Now the widely used nano-silver conductive paste mostly produced by European and other developed countries in which industrial production has already been realized. But production system is imperfect with variety of conductive paste needed be added. What's more, the forward development of electronic components requires them more urgently. Since the study on this area in China has just started, the research of nano-silver conductive paste used in the preparation of miniature and flexible wires has a crucial importance to the development of electronic components with smaller size and greater integration.This paper firstly studys and defines the preparation technology of silver nanoparticles. The silver nanoparticles was prepared by silver ion reduction through silver-ammino complex by means of Liquid Phase Reduction Method which is in two ways of using Ascorbic Acid as reducer without adding dispersant and Tannic Acid as reducer with Polyvinylpyrrolidone (PVP) as dispersant. Then the influences of preparation effects with different addition of reduction and dispersant are discussed, characterized and analyzed as well as the composition, appearance, structure and part of the functions of silver nanoparticles. Through the reading, the author analyzed the dispersion mechanism of dispersing silver nanoparticles with polyvinylpyrrolidone (PVP). This preparation technology is simple which can produce silver nanoparticles in good to excellent yields. The particle sizes of these nanoparticles with PVP as dispersant are in the range of 25 nm to 50 nm with average size is about 40 nm, which are narrowly distributed, while without dispersant, they are about 200 nm.Secondly, based on the study of dispersion principle of solid particles in organic media, this paper has investigated solid particles dispersion stabilization in conductive paste, and then has determined the formula and disperse method for nano-silver conductive ink separately using Emulsifier OP-10 and Triton X-100 as surfactants with Ethanol as solvents, Ethanol as solvent with Triton X-100 as surfactants, and both Ethanol and Terpineol as solvent. The results shows that solid content of nano-silver conductive ink prepared by secondary formula has up to 25wt%possessing better leveling property and uniformity whose film qualifys certain conductivity after being sintered at 500℃below.Finally, this paper has studied the formula and mixing-dispersion technology of nano-silver conductive paste. Nano-silver conductive paste are prepared by combining two kinds of pre-prepared conductive silver nanoparticles with different particle sizes equably mixed by means of graduation adding traces of copper powder, meanwhile, using Terpineol and Ethylcellulose and other organic matter functioned as organic carrier. Whereafter the author has discussed the effects on silver film conductivity resulted by different conductive paste composition, sintering time and temperature, characterized the surface topography of nano-silver conductive paste film sintered on glass substrate. With this formula, nano-silver conductive paste particles are equably dispersed and posses high viscosity which can form film sintered at 400℃below. |
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