MECHANICAL ALLOYING OF AN IMMISCIBLE ALPHA-FE2O3-SNO2 CERAMIC

A solid solution of about 6 mol% SnO2 in alpha-Fe2O3 has been prepared by mechanical alloying of alpha-Fe2O3 and SnO2 powder blends. This re sult demonstrates that high energy ball milling can be used to prepare metastable oxide solid solutions with an extended range of compositio ns in the immiscible ceramic oxide system. X-ray diffraction and Mossb auer spectroscopy investigations show that mechanical milling of alpha -Fe2O3 and SnO2 involves alloying on an atomic scale and that true sol id solution formation occurs. We suggest that the high defect concentr ation and the chemical enthalpy of Fe3+-O2--Sn4+ interfaces between na nostructured alpha-Fe2O3 and SnO2 regions may serve as a driving force for the formation of a solid solution in the immiscible ceramic syste m.