Sol-gel synthesis and characterization of tungsten-molybdenum solid solution nanoparticles

Abstract

In this work, WMo nanopowders were prepared by sol-gel synthesis combined with hydrogen reduction. The phase distribution of the powders with calcination and reduction at different temperatures was analyzed to figure out the effect of temperature on the reaction process. The calcined powders were further analyzed by thermogravimetric analysis (TGA) and differential thermal analysis (DSC). The phase composition, grain size and powder morphology of the resulted WMo nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The precursor calcined at 450 °C consisted of W0.4Mo0.6O3 and MoO3 phases which can be completely reduced to be pure WMo nanopowders with an average grain size of 20–40 nm at a low temperature of 700 °C for 1 h. The grain growth characteristics of the WMo nanopowders were investigated by analyzing the compacts annealed at temperatures ranging from 950 °C to 1400 °C for different time periods. The grain growth mechanism and the activation energy (Qg = 220 ± 21 kJ/mol) of WMo nanoparticles was also obtained.