A low temperature path to the preparation of ultrafine ferrites

Abstract

Ultrafine ferrites, {MFe_2O_4} where M = Mg, Mn, Fe, Co, Ni, and Zn, were prepd. by the combustion/decompn. in a melt of solid soln. precursors, hydrazinium metal hydrazinecarboxylate hydrates, {N_2H_5M_1}/{3Fe_2}/{3(N_2H_3COO)}3.{H_2O} (M = Mg, Mn, Fe, Co, Ni, and Zn). The precursors decomp. at low temps. (75-200°) with the evolution of large amts. of gases. Ultrafine ferrites having particle sizes 6-22 nm and surface area 100-140 {m^2}/g were obtained and characterized by x-ray powder diffraction, Moessbauer spectra, particle size anal., and surface area measurements.