Polyvinyl alcohol evaporation method for preparation of submicron chromite powders

Fine particles of chromites (MO.Cr2O3 where M=Mg, Zn, Ni, Co, and Cu) have been prepared by calcination of precursor powders prepared by evaporation of an aqueous solution of polyvinyl alcohol and stoichiometric amounts of the desired metal nitrates in appropriate mole ratios. The calcination temperatures, for the various chromite precursors, ranged from 350 to 450°C. The formation of the respective pure chromite phase in the calcined powders has been inferred from X-ray diffraction and infrared spectroscopy studies. The powders were found to be compositionally homogeneous and the average particle sizes, measured using transmission electron microscopy, were found to lie in the range 100-200 A. BCT/282