EFFECT OF MECHANICAL ACTIVATION ON THE SYNTHESIS OF ALPHA-FE2O3-CR2O3 SOLID-SOLUTIONS

Continuous alpha-Fe2O3-Cr2O3 solid solution series have been synthesized by two methods: (i) direct heating of coprecipitated hydroxides, and (ii) mechanical pre-treatment followed by heating. It is shown that mechanical treatment leads to a decrease in the preparation temperature of the solid solutions to 623 K. The formation of a continuous solid solution series by direct heating begins only at 773 K. The formation of the solid solutions was established by X-ray diffraction analysis, infrared and Mossbauer spectroscopy. The decrease in synthesis temperature of the alpha-Fe2O3-Cr2O3 Solid solutions is attributed to activation of the samples during their mechanical treatment. The samples obtained have large specific surface areas (up to 130 m2 g-1).