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Master's Dissertation
DOI
10.11606/D.85.2011.tde-17062011-103446
Document
Author
Full name
Tiago Felipe Andrade
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2011
Supervisor
Committee
Muccillo, Reginaldo (President)
Martinelli, José Roberto
Rocha, Renata Ayres
Title in Portuguese
Efeito da adição de óxido de zinco e de óxido de boro nas propriedades de zirconato de bário dopado com ítrio
Keywords in Portuguese
condutor protônico
espectroscopia de impedância
óxido de boro
óxido de zinco
zirconato de bário
Abstract in Portuguese
Compostos condutores protônicos de zirconato de bário dopado com ítrio, BaZr0,8Y0,2O3-δ, preparados por síntese de estado sólido, foram compactados e sinter izados com ZnO e B2O3 como aditivos. Os corpos cerâmicos sinter izados foram analisados por difração de raios X e espectroscopia de impedância. Superfícies polidas e atacadas termicamente foram observadas em microscópio de varredura por sonda. As medidas de densidade mostraram que a maior densificação foi obtida com óxido de zinco nas proporções de 2 e 5 peso%, atingindo aproximadamente 95% da densidade teórica. As medidas de resistividade elétrica evidenciaram a menor resistividade elétrica do composto cerâmico BaZr0,8Y0,2O3-δ, com 5 peso% de ZnO. Os aditivos de sinter ização, óxido de boro e óxido de zinco, foram eficientes para se obter compostos com menores valores de resistividade elétrica que os obtidos em compostos sinter izados sem aditivos.
Title in English
Effect of zinc oxide and boron oxide addition on the properties of yttrium-doped
Keywords in English
barium zirconate
boron oxide
impedance spectroscopy
protonic conductor
zinc oxide
Abstract in English
BaZr0.8Y0.2O3-δ, protonic conductors, prepared by the ceramic route, were pressed and sintered with ZnO and B2O3 sinter ing aids. The sintered pellets were analyzed by X-ra y diffraction and impedance spectroscopy. Polished and thermally etched surfaces of the pellets were observed in a scanning probe microscope. The highest values of apparent densit y, 95%T.D., were obtained with 2 and 5 wt.% ZnO. The lowest value of electr ical resistivit y was obtained in BaZr0.8Y0.2O3-δ, compounds with 5 wt.% ZnO. Boron oxide and zinc oxide sinter ing aids were efficient to improve the apparent densit y as well as the electr ical conductivit y of BaZr0.8Y0.2O3-δ, protonic conductors.
 
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2011AndradeEfeito.pdf (1.46 Mbytes)
Publishing Date
2011-06-22
 
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