XRD and Mössbauer spectroscopy investigation of Fe2O3-Al2O3 nano-composite

Fe2O3-Al2O3 nano-composites were synthesized by sol-gel means. The properties of samples sintered at various thermal treatment temperatures were investigated by X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The experimental results show that the γ- to α-Al2O3 transformation occurs at lower temperature after iron oxide doping. The samples obtained at 1173 K contained poorly crystallized γ-Al2O3 phase and an amorphous iron oxide. When the temperature of heating was increased to 1373 K, the sample was composed of α-Fe2O3/α-Al2O3 nano-composite and some solid solution. A superparamagnetic phenomenon was observed until the thermal treatment temperature reached 1373 K.