Formation of 25 mol % Fe₂O₃-Al₂O₃ solid solution by high-energy ball milling

The phase transformation process of a 25 mol % Fe₂O₃-Al₂O₃ powder mixture during high-energy ball milling has been studied by x-ray diffraction and Mössbauer spectroscopy. A metastable solid solution of 25 mol % Fe₂O₃ in Al₂O₃ with corundum structure has successfully been prepared after a milling time of 122 h. This demonstrates that the high-energy ball milling technique is able to prepare metastable solid solutions with an extended range of compositions in ceramic/ceramic systems with a positive heat of mixing.