Synthesis of Cr2O3 nanoparticles by mechanochemical processing Original Research Article

The synthesis of chromium oxide (Cr2O3) nanoparticles by mechanochemical reaction and subsequent heat treatment was investigated. A solid-state displacement reaction Na2Cr2O7+S→Cr2O3+Na2SO4 was induced during mechanical milling of Na2Cr2O7+S powder mixture, forming amorphous Cr2O3 nanoparticles. Annealing the as-milled powder under vacuum above 520°C resulted in the formation of crystalline Cr2O3 nanoparticles separated from each other in a salt matrix. A simple washing process to remove the matrix yielded Cr2O3 particles of 10–80 nm in size, having a plate-like morphology.