Banca de QUALIFICAÇÃO: NIVIA LUCIANA COSTA DE SIQUEIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : NIVIA LUCIANA COSTA DE SIQUEIRA
DATE: 09/06/2023
TIME: 09:00
LOCAL: meet.google.com/prf-ajao-zwe
TITLE:

Obtention of scheelite tapes via aqueous Tape Casting

KEY WORDS:

tungsten; scheelite; tape casting; tapes.

PAGES: 50
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Tungsten (W) is an element that belongs to the transition metals group with excellent thermal and electrical properties and corrosion resistance, which makes it a valuable material in various industrial applications. W does not occur in the Earth's crust as a free metal, and is typically found associated with other elements in mineral form, with scheelite and wolframite being the most abundant in nature. Scheelite, or calcium tungstate (CaWO₄), is a mineral of the wolframite group that has significant economic importance due to representing one of the largest amounts of tungsten production. In Brazil, the main stratiform deposits of scheelite are located in the state of Rio Grande do Norte (RN), in the Seridó region, constituting the largest concentration of tungsten in the country. The exploitation of this mineral has shown to be responsible for causing various negative environmental impacts in the mined areas, therefore, there is a clear need to develop technologies to mitigate the impacts caused by the extraction and beneficiation of this abundant mineral in the state. Thin films and solids made with tungsten compounds have great potential for dielectric, electronic, and optoelectronic applications, and can be produced by different production methods. Aqueous ape casting is one of the simplest and well-established methods for the production of films and tapes, as well as being safe and non-toxic. Considering the cited facts, the objective of the present study was to produce scheelite tapes and analyze their properties. For this, five tapes were produced with compositions varying the amount of scheelite residue (SR) and scheelite concentrated in W (SC). The powders were subjected to physical-chemical characterization through fluorescence and X-ray diffraction tests, as well as rheology analysis of the produced suspensions. The green tapes were characterized through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (TGA), and dielectric measurements, in order to evaluate the morphology, surface composition, thermal behavior, dielectric properties of the tapes, and their possible applications.

COMMITTEE MEMBERS:
Presidente - 1149564 - WILSON ACCHAR
Externo à Instituição - HUGO PLÍNIO DE ANDRADE ALVES - IFPB
Externo à Instituição - VAMBERTO MONTEIRO DA SILVA - IFPB