Banca de QUALIFICAÇÃO: PAULO ROBERTO CUNHA DOS SANTOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : PAULO ROBERTO CUNHA DOS SANTOS
DATA : 21/06/2018
HORA: 16:00
LOCAL: Sala de aula do Química 1
TÍTULO:

STUDY OF MAGNETIC PROPERTIES IN COMPOSITE OF NICKEL FERRITE IN POLYMERIC PVA MATRIX

PALAVRAS-CHAVES:

Nickel ferrite, Composites, Poly(vinylalcohol).

PÁGINAS: 120
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Determinação de Estrutura de Compostos Inorgânicos
RESUMO:

Materials produced by the physical mixing of two or more charge-added polymers have attracted much interest in research, industry and commerce in recent decades. The resulting material of this blend is called composites, from which new products with intermediate properties between the pure components can be obtained or maintaining the same properties suiting a better handling or stability. The results sought in these composites are low density, good mechanical strength, excellent corrosion resistance, rigidity or flexibility, good electromagnetic properties, low cost, durability and competitiveness compared to conventional materials. In this work, films of composites formed by a polymer matrix of 99% hydrolyzed poly (vinylalcohol) - PVA incorporated with ceramic load of Nickel Ferrite (NiFe₂O₄) in concentrations of 10, 20, 30, and 50%, respectively. The combustion method was used to obtain the Ferrite, and it was calcined at 750°C. All materials obtained were characterized by X-ray diffraction (XRD), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) with EDS, Vibrating Sample Magnetometer (MAV) and Electron Paramagnetic Resonance Spectroscopy (RPE). The results of the XRD, together with the Rietveld refinement, showed a mean crystallite size of 32.5 nm and formation of secondary phases of gFe₂O₃ and Ni0. The SEM spectra showed spherical and porous particles, while the data collected from the EDS are in line with the XRD result. The MAV magnetic measurements have characteristics of soft magnetic materials and the EPR spectra present the presence of Fe³⁺ free radicals.

MEMBROS DA BANCA:
Presidente - 350633 - ADEMIR OLIVEIRA DA SILVA
Interno - 348475 - DJALMA RIBEIRO DA SILVA
Externo à Instituição - ELANIA MARIA FERNANDES SILVA - UFRN