Banca de DEFESA: ANDRÉ BARONI JERMOLOVICIUS
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : ANDRÉ BARONI JERMOLOVICIUS
DATA : 12/08/2021
HORA: 14:00
LOCAL: modo remoto por videoconferência: meet.google.com/xhv-fhse-dxr
TÍTULO:
EFFECTS OF COMPOSITION, TEMPERATURE AND TIME OF HYBRID MICROWAVE SINTERING ON THE MICROSTRUCTURE AND PROPERTIES OF A TRANSLUCENT PORCELAIN
PÁGINAS: 165
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Cerâmicos
RESUMO:
The results of a statistically designed experiment using the central composite design (CCD) method for hybrid sintering with microwave of translucent porcelain to establish a relationship between the independent variables are presented: a) mass ratio between kaolin and potassium feldspar, b) sintering temperature, c) holding time at the sintering temperature and the properties and characteristics of the sintered product. The properties analyzed were: bulk density, water absorption, light transmittance, and dielectric properties. Also, the microstructure evolution of the translucent porcelain was analyzed by scanning electron microscopy coupled with energy dispersion spectroscopy. Initial tests were performed to determine the extreme values of the three variables studied in the CCD. Specimens prepared by uniaxial pressing were sintered in a microwave oven equipped with a firing chamber with a silicon carbide susceptor. In initial tests, the relevance of using intermediate preheating steps rather than a single microwave heating cycle was determined. With the results obtained with the CCD, analysis of variance with factorial data and multilinear and quadratic regressions were performed. Quadratic equations for density, water absorption, and dielectric properties were obtained. For transmittance, multilinear equations were obtained. From the numerical results, the following stand out: the maximum density at 1252 °C with 3 min of holding time (2.44 g/cm3), the minimum water absorption at 1248 °C with 3.8 min (0.41%), the highest light transmittance value was at 1274 °C with 6.4 min (23.9%), and the highest values of dielectric constant and loss tangent occurred, respectively, at 1248 °C (3.81) and 1244 °C with a soaking time of 3 min (0.24). For comparison, firings were carried out in a conventional electric furnace. As a result, it was observed that microwave sintering produced porcelain with higher density and lower water absorption compared to conventional sintering.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1671394 - HUMBERTO NAOYUKI YOSHIMURA
Membro Titular - Examinador(a) Externo à Instituição - ROMUALDO RODRIGUES MENEZES - UFCG
Membro Titular - Examinador(a) Externo à Instituição - ANDRÉ LUIZ MOLISANI
Membro Suplente - Examinador(a) Interno ao Programa - 1948454 - VANIA TROMBINI HERNANDES
Membro Suplente - Examinador(a) Externo à Instituição - EDUARDO VICTOR DOS SANTOS POUZADA - IMT