Navegando por Autor "Benincá, Renata"
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Artigo Structural and spectroscopic characterization of Al2−x Cr x O3 powders obtained by polymeric precursor method(Springer, 2007-03-21) Cava, Sérgio; Benincá, Renata; Tebcherani, Sérgio Mazurek; Souza, Iedo A.; Paskocimas, Carlos Alberto; Silva, Elson Longo da; Varela, José A.Al2O3 and Al2−xCrxO3 (x = 0.01, 0.02 and 0.04) powders have been synthesized by the polymeric precursors method. A study of the structural evolution of crystalline phases corresponding to the obtained powders was accomplished through X-Ray Diffraction and UV-vis spectroscopy (reflectance spectra and CIEL∗a∗b∗ color data). The obtained results allow to identify the γ -Al2O3 to α-Al2O3 phase transition. The single-phase α-Al2O3 powder was obtained after heat treatment at 1050 ◦C for 2 h. The results show that the green to red color transition and ruby luminescence lines observed for the powders of Al2−xCrxO3 are related to the γ to α-Al2O3 phase transition and the temperature and time range for such transition depends on the chromium content