Resumo

SALAZAR-PEREZ, A. J. et al. Structural evolution of Bi ₂ O ₃ prepared by thermal oxidation of bismuth nano-particles. Superf. vacío [online]. 2005, vol.18, n.3, pp.4-8. ISSN 1665-3521.

Bismuth nano-sized particles were prepared by the chemical reduction method. These particles were characterized by HR-TEM, X-Ray Diffraction and Micro-Raman Spectroscopy. In order to obtain bismuth oxide, the as-obtained bismuth nano-particles were thermally treated in air at various temperatures in the range 100-750 0C during 30 min. The thermally treated samples were studied by Micro-Raman Spectroscopy. Additionally, information on the chemical composition and morphology was obtained by Energy Dispersive Spectroscopy and Scanning Electron Microscopy, respectively. Results show that bismuth nano-particles were oxidized at 100 oC and transformed into three of the five phases of Bi2O3 reported in literature; the obtained phase depends on the annealing temperature. The β-Bi2O3 phase was obtained for 200-300 0C, α-Bi2O3 for 400-600 0C and finally γ-Bi2O3 for 700-750 0C.

Palavras-chave : Bismuth oxide; Thermal oxidation; Micro-Raman spectroscopy.