Abstract:

Nano-sized zinc oxide was prepared by thermal decomposition process of basic zinc carbonate,with zinc nitrate as zinc source,and sodium carbonate and ammonium hydrogen carbonate as precipitants.The formation process,growth kinetics equa-tion,micromorphology and dispersion state of zinc oxide samples by two kinds of carbonates were analyzed by thermogravime-tric analysis,crystal form test,average particle aize test and microscopic morphology.It was found that zinc oxide was obtained directly at 200 ℃ using ammonium hydrogen carbonate as precipitant; while using sodium carbonate as the precipitant,the precursor changed into zinc carbonate at 200~250 ℃,and then completely transformed into zinc oxide above 300 ℃.The growth process of nano-sized zinc oxide prepared by two precipitants was in accordance with the growth relationship of differ-ent exponential equations.The growth of nano-sized zinc oxide prepared using sodium carbonate as precipitant was satisfied the equation of y=2.775 04e^{0.004 76x},while the growth of nano-sized zinc oxide prepared using ammonium hydrogen carbonate as precipitant was satisfied the equation of y=5.152 96e^{0.002 85x}.Smaller grain size of zinc oxide was prepared by using ammonium bicarbonate as the precipitant at the same temperature through the growth kinetics equations.Smaller particle size of zinc ox- ide was prepared by using ammonium bicarbonate as precipitant through particle size distribution and electron microscopy.

Key words: carbonate, precipitant, thermal decomposition, nano-sized zinc oxide