Banca de DEFESA: MATHEUS VERÍSSIMO RODRIGUES
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : MATHEUS VERÍSSIMO RODRIGUES
DATE: 30/06/2020
TIME: 08:30
LOCAL: ONLINE
TITLE:
Synthesis and characterization of mixed copper and nickel ferrites using the combined EDTA/Citrate complexation method.
KEY WORDS:
ceramics; nickel and copper ferrite; complexation method; characterizations.
PAGES: 100
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Orgânicos
SUMMARY:
This paper consists in the synthesis and characterization steps in order to obtain a mixed nickel and copper ferrite (NixCu1-xFe2O4), in which the nickel’s presence varies from 0 to 100%, with gaps of 20% between each sample. As a synthesis route, complexation by EDTA and citric acid as chelating agents was the chosen method. Once the process began with the EDTA dissolving by ammonium hydroxide, hydrated iron III, copper II, and nickel II nitrates, at stoichiometric proportions, were added. Then citric acid was added to the mixture, with the intent that the proportion between EDTA, citric acid and the metallic cations corresponded to 1:1.5:1, and that was heated to 80 ºC. Succeeding the formation of a gel, the precursors were taken to the muffle at 230 ºC for three hours and, afterwards, incinerated for four hours at three different temperatures, 500 ºC, 600 ºC e 700º C, creating distinct samples. X-ray diffraction (XRD) analysis was performed on the samples following two procedures, one slower and one faster, aiming to obtain the crystalline structure profile and to compare than with models from the Xpert software and, then, refined on GSAS/EXPGUI. Two different scanning electron microscopy methods (SEM) were utilized, for two distinct magnification spectra: a desktop device and one with a field emission gun (FEG), attached to a energy dispersive spectroscopy (EDS). In both situations, imagens containing the synthetized ceramics were obtained and, aided by the EDS, it was possible to analyze the ratio between each ferrite’s atomic components. As a result from the XRD analyses and refinement, it was possible to notice that the peaks present better definition at higher incineration temperatures, correspondence to the materials’ cards found on X’Pert and the absence of multiple phases on the final products. Regarding the microscopies, the desktop device provided images with low resolution, because the synthetized materials has smaller dimensions than those of the method’s limitations. The SEM-FEG, on the other hand, allowed a better visualization of the particles, whose size is nanometric and forms, in some cases, an octahedra structure. In order to evaluate the obtained solids, this paper recommends further characterization application studies.
BANKING MEMBERS:
Presidente - 2929066 - ANDRE LUIS LOPES MORIYAMA
Externa ao Programa - 2668814 - MAGNA ANGELICA DOS SANTOS BEZERRA SOUSA
Externa à Instituição - MAYARA FELICIANO GOMES
Externa à Instituição - SUYLAN LOURDES DE ARAÚJO DANTAS
Externa à Instituição - YARA FELICIANO GOMES - UFRN