Control of the Composition and Structure of Fe–O Nanoparticles during Fe₃O₄ Electron Beam Evaporation

Abstract

The paper examines the structure of porous Fe₃O₄ + NaCl condensates and analyzes the phase and chemical composition and sizes of Fe₃O₄ nanoparticles pro-duced by electron beam evaporation and condensation in vacuum. The high adsorptivity of porous Fe₃O₄ salt matrix relative to air oxygen is shown. It decreases when iron concentration in the condensate increases. Thermogravimetric analysis is used to study the kinetics of relative change in the weight of porous NaCl and Fe₃O₄ + NaCl condensates when heated to 650°C and cooled in air. The results are considered in terms of physical and chemical adsorption. Stabilized colloidal systems of magnetite nanoparticles are obtained. Photon correlation spectroscopy is used to determine their quantitative size distribution in a water solution with surface active substances. The physical method for obtaining nanoparticles in electron beam vacuum units is highly efficient and competitive with previous methods for synthesis of nanoparticles.