Banca de DEFESA: KÍVIA FABIANA GALVÃO DE ARAÚJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : KÍVIA FABIANA GALVÃO DE ARAÚJO
DATE: 23/01/2023
TIME: 13:30
LOCAL: Sala Virtual
TITLE:

Obtaining and Characterrization of nanostructured powders of  CuNb2O6 sinthesized via gas-solid reation prosthetic sol-gel

KEY WORDS:

Keywords: CuNb2O6, Copper niobate, Synthesis, Sol-Gel, solid-state reaction, Milling.

PAGES: 88
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Metalurgia de Pó
SUMMARY:

In recent decades, Brazil has been seeking to expand its research on Niobium,
motivated by the potential of its properties, as well as its abundance in our territory. Among
these, Copper Niobate (CuNb2O6) has been standing out in science due to its excellent
properties for very current technological applications such as solar cell devices, microwave
devices, photocathodes, ultrashort pulsed infrared laser sensors, for example. Aiming at this
vast possibility of applications, in this study, therefore, CuNb2O6nanoparticles were produced
using two routes, with simple methodologies, low cost and that allow obtaining nanoscale
particles, solid state reaction with variation in milling time and gelatin-modified protein
sol-gel using two combinations of precursors, Nb2O5+ CuO e Nb2O5+ Cu(NO3)2.3H2O. After
obtaining, the powders were calcined in a muffle with temperatures in the range of 500 °C to
1000 °C, for 3 h, heating rate of 5 °/min and oxygen atmosphere. Posteriorly the particles
were characterized by means of X-ray Diffraction (XRD), Scanning Electron Microscopy
(SEM) and Energy Dispersive Spectroscopy (EDS) analysis. The results for the solid state
reaction route showed that the increase in milling time led to a reduction in temperature in the
formation of the monoclinic phase, as well as the complete formation of the orthorhombic
phase at the typical temperature of obtaining, in a short time, in addition to an improvement in
the homogeneity of the powder. For the synthesis via protein sol-gel, the XRD results show
that, at 700 °C, the formation of the monoclinic phase begins for both combinations of
precursors, being completely obtained at 900 °C when using CuO. The orthorhombic phase
was obtained completely at 1000 °C in the two combinations of precursors, all samples with
total formation of polymorphs showed good dispersivity. For both routes, the resulting
powdersdonotcontainevidenceofcontaminationandthecharacteristicparticle
morphologies are coherent with the literature. The sizes of the crystallites obtained from the
XRD,bytheScherrerequation,indicatedanincreaseproportional to the increase in
temperature, however, all the powders obtained by the two routes presented crystallites in
nanometric order

COMMITTEE MEMBERS:
Presidente - 345842 - UILAME UMBELINO GOMES
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externo à Instituição - HEYTOR VITOR SOUZA BEZERRA DE AZEVEDO
Externa à Instituição - MARIA JOSÉ SANTOS LIMA
Externo à Instituição - RAFAEL ALEXANDRE RAIMUNDO