Banca de DEFESA: SERGIO AUGUSTO NASCIMENTO DE FRANÇA JUNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : SERGIO AUGUSTO NASCIMENTO DE FRANÇA JUNIOR
DATE: 08/01/2020
TIME: 09:00
LOCAL: Sala de aulas do PPGCEM
TITLE:

Obtaining dielectric substrates based on calcium silicate with different additions of h-BN by tape casting.

KEY WORDS:

Tape casting, ceramic laminates, vitroceramics, h-BN, high frequency substrate.

PAGES: 84
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUMMARY:

In recent years, the considerable progress of the IoT, microwave telecommunications, satellite transmission systems and dense microelectronic circuits has resulted in a growing demand for new low dielectric loss materials. Ceramic substrates for these purposes should generally have low relative dielectric constant and have low dielectric loss under high operating frequencies and high thermal conductivity. Hexagonal boron nitride (h-BN) has great potential as a substrate for high frequency applications due to low constant and dielectric loss, as well as high thermal conductivity. Glass ceramic materials have also been widely used due to their low cost and excellent dielectric properties. In view of this, the objective of the present work was to obtain multilayer calcium silicate ceramic substrates with h-BN additions (1 wt. %, 3 wt. % and 5 wt. %) conformed by tape casting in order to evaluate their use as high frequency substrates. The viscosity of the ceramic suspensions was analyzed by rheological tests and the green ceramic tapes were subjected to thermal analysis (ATG). The ceramic tapes were laminated and sintered at three temperatures: 950 ° C, 1000 ° C and 1050 ° C. The Sintered laminates were characterized by X-ray diffraction, Raman spectroscopy, density and porosity assays, and field emission scanning electron microscopy (SEM-FEG). Finally, dielectric properties of green and sintered laminates were obtained. Reflection peaks concerning wolastonite and cristobalite phases were found in all compositions, as well as a characteristic hexagonal boron nitride peak in compositions containing h-BN. The high relative apparent porosity values found in all compositions determined the low relative dielectric constant values (between 1.99 and 2.35), In general, the obtained compositions showed low dielectric losses, mainly in the samples containing h-BN, and this was evident in a wide frequency range, from 0.1 GHz to 1.5 GHz. The composition containing 5 wt. % h-BN showed dielectric losses in the order of 10-4 , thus having great potential for application as a high frequency substrate.

BANKING MEMBERS:
Externa à Instituição - Ana Paula da Silva Peres - UFRN
Externo à Instituição - Antonio Carlos Silva da Costa - UFRN
Presidente - 1149564 - WILSON ACCHAR