Banca de QUALIFICAÇÃO: DIEGO TAVARES DE FRANÇA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : DIEGO TAVARES DE FRANÇA
DATA : 11/07/2019
HORA: 10:00
LOCAL: Sala de Seminários I – DFTE/UFRN
TÍTULO:

Synthesis along with structural and magnetic characterization of xTiO₂-(1-x) α-Fe₂O₃ composite

PALAVRAS-CHAVES:

High energy milling, Titanium oxide, Hematite, Pseudobrookite and Spin glass

PÁGINAS: 100
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

Mixedbinaries oxides TiO₂/α-Fe₂O₃ type are good catalysts and have enhanced photocatalytic properties when applied to degradation of pollutants and organic gases detection. Among the various compositions of these oxides, the Fe₂TiO₅, known as pseudobrookite, is an oxide that have been attracting interest of theoretical and working field due to the Anisotropic magnetic properties. The present work synthesized xTiO₂-(1-x)α-Fe₂O3 compounds with x equal 0.3; 0.5 and 0.7. The composites were obtained from precursors powders (anatase) TiO₂ and α-Fe₂O₃, which were stoichiometrically mixed and ground for 24 hours, being thermally treated at temperatures of 700° C, 900° C and 1100° (C) during 3 hours. Later, the samples were characterized by X-ray diffraction, Scanning Electron Microscopy and Vibrating Sample Magnetometry. The refinement of the diffractograms highlighted that there was no formation of new phases to ground compounds. At the temperature of 700° C, for x = 0.5 and 0.7, it begins to emerge the phase TiO2 (rutile). While at 900° C, all series presented the presence of the pseudobrookite. In addition, the X-ray diffraction also revealed the formation of pseudobrookite with phase concentration of 95.10% for x = 0.5 and calcined at 1.100° C. This result highlights the used route as a simple and low cost approach for the production of Iron-Titanium oxides, especially  Fe₂TiO₅. For this sample, the presence of spin glass, type cluster, was observed at approximately 56 K of temperature and presence of Dzyaloshinsskii-Morya interaction. Based on the SEM-EGF micrographs, one can observe that all samples feature agglomerate and nodular morphologies.

MEMBROS DA BANCA:
Presidente - 1675199 - SUZANA NOBREGA DE MEDEIROS
Interno - 2492756 - JOAO MEDEIROS DE ARAUJO
Externo ao Programa - 1508681 - FELIPE BOHN