Production of Nanopowders by the Evaporation–Condensation Method Using a Focused Microwave Radiation

Abstract

The formation of the WO₃, SnO₂ and ZnO metal oxide nanoparticles from vapors generated during evaporation of the material by a focused beam of microwave electromagnetic radiation with a frequency of 24 GHz and an energy flux density of more than 10 kW/cm² is studied experimentally. The specific surface area of the nanopowders obtained over the entire range of the process parameters ranged from 1.9 to 8.3 m²/g, which corresponds to an average particle size of 430 to 95 nm. The possibility to control the dispersion composition of the powders is demonstrated. Increasing the quenching air flow increases the specific surface area of the powder obtained. The maximum evaporation rate of WO₃ exceeded 100 g/h.