Amorphous iron-chromium oxide nanoparticles prepared by sonochemistry

作者：Nguyen Dang Phu; Trinh Xuan Sy; Hoang Thanh Cao; Nguyen Ngoc Dinh; Le Van Thien; Nguyen Minh Hieu; Nguyen Hoang Nam; Nguyen Hoang Hai^*

来源：Journal of Non-Crystalline Solids, 2012, 358(3): 537-543.

DOI：10.1016/j.jnoncrysol.2011.10.035

• Crystallization process
• Amorphous iron oxide
• Sonochemistry
• Phase transition
• Magnetic property

Amorphous Fe2O3 and Fe1.9Cr0.1O3 materials have been prepared by sonochemical method. X-ray diffraction patterns, transmission electron microscopy. Raman and infrared spectra, differential scanning calorimetry, MOssbauer and magnetic measurements revealed many interesting behaviors of the samples. Reaction to form the materials only occurred at the preparation temperatures of 70 degrees C or above. Upon heating, the sample prepared at 70 degrees C presented a strong ferromagnetic behavior due to the presence of the magnetite phase coexisting with the hematite phase whereas the samples prepared at higher temperatures presented only the existence of the hematite phase. Thermal analyses of the sample prepared at 80 degrees C revealed three exothermic peaks which were corresponding to the phase changes of dehydroxylation, crystallization of the maghemite phase and maghemite-hematite transition, respectively. The activation energies of the phase changes deduced from the thermal analyses showed that the presence of Cr enhanced the activation energy which can slow down the ageing effect of the amorphous state when being used in practice.

• 出版日期2012-2-1