The effect of surfactants on the particle size of iron, cobalt and nickel nanopowders

Abstract

This paper studies the effect of surfactants on the particle size of metal nanopowders (NPs): iron, cobalt and nickel synthesized using chemical-metallurgy method – hydrogen reduction of hydroxide compounds FeOOH, Co(OH) 2 and Ni(OH) 2 at 400, 285, and 280 °С, respectively. These hydroxides were pre-synthesized via chemical deposition from the corresponding nitrate solutions with NaOH alkali solution (10 wt.%) using sodium dodecyl sulfate (SDS) (0.1 %) and ethylenediaminetetraacetic acid disodium salt (EDTA) (0.3 %). The obtained NPs were studied using such methods as X-ray diffractometry (XRD), scanning electron microscopy (SEM), and measurements of the specific surface area by low-temperature nitrogen adsorption. According to XRD shows that all the obtained samples of NPs Fe, Co and Ni contain pure metallic phases. The results of electron microscopic analysis and measurement of the specific surface area of powder samples show that the addition of various surfactants to the initial synthesis medium of hydroxide compounds has a significant effect on the size and morphology of the obtained NPs. It was found that the addition of 0.1 % SDS leads to a decrease in the average size of the obtained particles, and the presence of 0.3 % EDTA contributes to the formation of larger metal particles. It was shown that the use of 0.3 % EDTA in deposition of initial hydroxide precursors makes it possible to obtain metal NPs with the narrowest crystallite size distributions.