Caracterização de vidros niobofosfatos para aplicação em selagem em célula a combústivel de óxido sólido / Characterization of niobophosphate glasses for solid oxide fuel cell (SOFC) sealing

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/03/2010

RESUMO

Solid oxide fuel cells (SOFC) are devices which generate d.c. power by the oxidation of hydrogen molecules. These devices can have a multilayer plane design containing a cathode, an anode, a solid electrolyte, and a sealing material. The sealing, which is the subject of this study, has to be chemically stable at relatively SOFC operational condition in oxi-redox atmospheres, electrical insulator, with a thermal expansion coefficient matching other components, and, in of glass, the viscosity must be relatively high. The aim of the present work is to characterize niobophosphate glasses which will be used as sealant precursors of Solid Oxide Fuel Cell with a plane design. Niobophosphate glasses, named Nb30, Nb37, Nb40, and Nb44 according to the niobium content, were investigated for this purpose. The sealing was performed by mixing glass powder with ethanol which was applied over the substrate. Later, a heat treatment was performed to consolidate the sealing. Glass powder and devitrified glass pellets were characterized by different techniques. The thermal expansion coefficient, electrical resistivity, and the X-rays diffraction pattern were determined for these materials. Scanning electron microscopy was also used to visualize the sealing/ substrate interface, and to evaluate the adhesiveness, wetability, apparent mechanical resistance in alumina substrates and in other SOFC components. The sealants were tested in SOFC, and also submitted to simulating thermal cycles.

ASSUNTO(S)

célula a combustível de óxido sólido (sofc) niobophosphate glasses sealing selagem solid oxide fuel cells (sofc) vidros niobofosfato

Documentos Relacionados