Preparation of micro-sized and uniform spherical Ag powders by
novel wet-chemical method
novel wet-chemical method
(1. Division of Optoelectronic Materials & Micro/Nano Manufacturing,
Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China;
2. Department of Materials Science and Engineering,
Huazhong University of Science and Technology, Wuhan 430074, China)
Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China;
2. Department of Materials Science and Engineering,
Huazhong University of Science and Technology, Wuhan 430074, China)
Abstract: A novel wet-chemical method was presented for the preparation of the micro-sized and uniform spherical Ag powders on a mass-production scale. The well-defined particles were synthesized by mixing the iron(II) sulfate heptahydrate solution with silver nitrate solution directly by high-speed stirring at room temperature. It is found that a large number of micro-sized and uniform spherical particles with rough surfaces are obtained. The mass ratio of iron(II) sulfate heptahydrate to silver nitrate greatly affects the shape of particles, and when it is relatively low, spherical particles cannot be obtained. The reaction temperature has a great impact on the particle size. As the reaction temperature increases from 8 to 15 °C, the mean diameter of particles decreases from 3.5 to 1.6 mm. The additive n-methyl-2-pyrrolidone improves the surface smoothness and compactness of the particles while the particle size is kept unchanged. Scanning electron microscopy, X-ray diffractometry and energy dispersive X-ray analysis were used to characterize the particle products.
Key words: silver powder; wet-chemical method; iron(II) sulfate heptahydrate; micro-sized powder