Modified sol-gel synthesis of ultradispersed powders of cobalt, nickel, molybdenum, and tungsten oxides and composites based on them

Abstract

An approach is proposed to the creation of laboratory technology of ultradispersed VI and VIII groups metal oxide powders, as well as composites based on them, intended to provide a broad range of fine-grained ceramics. The study covers the modified sol-gel synthesis of cobalt, nickel, tungsten, and molybdenum oxides powders and composites based on them by MeVIIIMeVIO x -type having a particle size of 10 to 1000 nm. The influence of the reaction mixture composition on the phase composition of such binary systems was shown. The conditions of obtaining of metal oxide powders with certain dispersions were investigated: the molar ratio stabilizer/metal, thermal treatment mode, etc. The effect of various sol stabilizers, hexamethylenetetramine, N,N-dimethyloctylamine, and tetraethylammonium hydroxide, on the dispersity of metal oxide powders was shown. All synthesized powders have been characterized using instrumental methods: X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, and a laser confocal microscope. The optimal parameters of modified sol-gel synthesis of ultradispersed powders have been determined: the qualitative and quantitative compositions of the reaction mixture, thermal treatment, etc. The developed approach allows to synthesize ultradispersed metal oxide particles with a given size and vary it within 10–130 nm range with a precision of 20–30 nm.