X-ray Studies on the Ferrite-Haematite Solid Solutions

Abstract

The variation of the lattice dimension of the solid solution system, NiFe 2 O 4 –Fe 2 O 3 , and the precipitation process of α-Fe 2 O 3 therefrom were investigated by X-ray analysis. These quenched solid solutions possess unstable inhomogeneities originating in the localized oxidization. When annealed at certain temperatures, the solid solution tends to become stabilized by the precipitation of α-Fe 2 O 3 . The activation energy for the precipitation was found to be ca 1.03 ev. The solubility of Fe 2 O 3 in NiFe 2 O 4 was determined at various temperatures, and the heat of dissolution was found to be 1.3 ev.