Nano-Fe particles were prepared by an are plasma method and sintered in air atmosphere at different temperatures to obtain nano-Fe2O3. The morphology and phase structure of nano-Fe2O3 particles were studied by TEM and XRD methods. TEM results show that the shapes of Fe2O3 particles are spherical and the average particle size is about 50 nm. Also, the Fe particles sintered at temperatures below 600 degrees C consist of lighter cores and darker outer shells, the latter disappear at temperatures above 600 degrees C. XRD results show that a phase transformation from gamma-Fe2O3 to alpha-Fe2O3 occurs with increasing temperature. alpha-Fe2O3 was found at temperatures as low as 200 degrees C but only alpha-Fe2O3 exists above 600 degrees C.
