Investigation of Nanocrystallized α-Fe₂O₃ Prepared by a Precipitation Process

Nathalie Pailhé (1) , Jérôme Majimel (1) , Stanislav Pechev (1) , Pierre Gravereau (1) , Manuel Gaudon (1) , Alain Demourgues (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Nanocrystallized hematite α-Fe₂O₃ was synthesized by a precipitation route followed by annealing at moderate temperature (400 °C). The final product was investigated by X-ray diffraction and scanning and transmission electron microscopies. The strong influence of the weak anisotropy of crystallites on the X-ray diffractogram profile is highlighted and discussed. From the Williamson and Hall plot, it appears indubitably that the short length of the crystallite shape corresponds to the c directions of the hexagonal unit cell. Thus, a platelet model was used to simulate crystallite morphology for the refinement process. The anisotropy of the crystallites in the present material is “moderate” since the ratio between large length and short length does not exceed 2. Nevertheless, this weak anisotropy has got a strong influence on the X-ray pattern.

Mots clés: Crystallography; X-ray diffraction; Nanocrystals; Transmission electron microscopies

Domaines: Matériaux

Nathalie Pailhé, Jérôme Majimel, Stanislav Pechev, Pierre Gravereau, Manuel Gaudon, et al.. Investigation of Nanocrystallized α-Fe₂O₃ Prepared by a Precipitation Process. Journal of Physical Chemistry C, 2008, 112 (49), pp.19217-19223. ⟨10.1021/jp8053313⟩. ⟨hal-00380294⟩