Method for preparing nano zinc oxide powder possessing high electric conductivity

Abstract

The invention relates to a preparation method of nano-scale zinc oxide powder. The method is to drop the mixed salt solution of the soluble salt of zinc and the soluble salt of doping elements aluminum, gallium, indium, yttrium, scandium, tin, germanium, silicon and the precipitant into the water at the same time, while controlling the temperature of the whole reaction system Co-precipitate under the conditions of pH and pH value to generate doped zinc oxide precursor basic zinc carbonate, and obtain doped nano-zinc oxide conductive powder material by roasting in a mixed atmosphere of hydrogen and argon. The particle size of the conductive powder material prepared by the invention is small, the particle size distribution is uniform, and the average particle size is about 10-80nm. The volume resistivity of the powder can reach 2.5×10 -3 Ω·cm, its electrical conductivity is superior to samples prepared by the plasma method and the gas phase method currently on the market. The preparation method of the invention further improves the whiteness and electrical conductivity of the zinc oxide powder, and further reduces the cost.

Description

technical field [0001] The invention relates to a method for preparing zinc oxide powder, in particular to a method for preparing nanoscale inorganic oxide powder with high electrical conductivity. Background technique [0002] With the rapid development of the electronics industry and the improvement of people's living standards, conductive powder, as a functional filler in the preparation process of plastics, coatings, fibers, etc., has antistatic, electromagnetic shielding and other properties, and has begun to attract people's attention. focus on. At present, conductive powders mainly include: metal powders such as silver, nickel, etc., non-metallic powders such as graphite, carbon black, etc., metal oxides such as zinc oxide, antimony oxide, etc., and composite powders and iodides such as SnO 2 -In 2 o 3 Coated mica or inorganic mineral powder, copper iodide, etc. Metal and carbon black materials have excellent electrical conductivity, but they are not easy to dispe...

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Problems solved by technology

The co-precipitation preparation method that appeared later has also been studied a lot (Gёrald Djega-Mariadasson, et al. US Patent: 4894185, 1990; Takao Hayashi, et al. US Patent: 5312614, 1994.), generally it is a preliminary control of experimental conditions In this case, the mixed salt solution of zinc is directly added dropwise to the precipitant to cause co-precipitation. Although the doping effect can be obtained relatively better than the previous solid-phase mixing and sintering method, it still causes the precipitation of doped ions and zinc ions. It cannot be completely uniformly precipitated at the same time, and the doping elements cannot be completely uniformly doped into the zinc oxide lattice. Although the obtained particles are more uniformly doped than the previous method, the performance of the powder is better than that of the previous solid-phase mixing sintering method. The performance of the prepared powder has also been greatly improved, but the electrical conductivity of the final powder is still relatively poor (in the most ideal case, when using the optimal doping content of non-ferrous metal Sn and rare earth element Ga, The powder synthesized at pH=9.0 was sintered at 400°C for 1 hour under hydrogen atmosphere, and the volume resistivity was 7.4×10- 1 Ω·cm conductive zinc oxide powder), the particle size is relatively large, and there is a relatively serious agglomeration phenomenon

Conductive zinc oxide powder produced by gas phase method (Yoshimaru, et al. US Patent: 5560871, 1996) and plasma method (Yuan Fangli et al., Chemical Metallurgy, 1998, 19(3): 212-216) reported in previous years (The performance parameters of the powder are shown in Table 1) The performance has been greatly improved than before, but there are also problems such as whiteness and low electrical conductivity: the cost of preparing conductive zinc oxide powder by the gas phase method is low, but the particles The size is basically at the micron level, and its particle size is too large for the application in the field of nano-functional materials; while the conductive zinc oxide powder prepared by the plasma method has a relatively suitable particle size and good dispersion, but its preparation cost is high. very high

These existing problems have limited the application of current conductive zinc oxide powder to a large extent.