resumo
Two examples were selected to emphasize the potential of grain boundary engineering in the performance design of heterogeneous ceramics. Gadolinium-doped ceria-based powders were co-fired with additions of silica, and silica and lanthanum oxide, to test the silica scavenging role of lanthanum. The formation of one ionic conducting secondary phase, instead of an insulating phase, was attempted. The structural, microstructural, and electrical characterization of these samples confirmed the formation of one apatite-type lanthanum silicate-based phase and a significant enhancement of the grain boundary conductivity of these materials. One second approach addressed the formation of one mixed conductor, with electronically conductive grain boundaries, surrounding the grains of one lanthanum gallate-based electrolyte (core-shell type microstructure). Fe-doped grain boundaries were formed by selective Fe-diffusion (thermally assisted) from lanthanum ferrite screen printed layers. Combined microstructural and electrical characterization showed that the adopted solution was also effective.
palavras-chave
MODIFIED BARIUM-TITANATE; CORE-SHELL STRUCTURES; ELECTRICAL-PROPERTIES; MECHANICAL-PROPERTIES; IONIC-CONDUCTIVITY; OXYGEN PERMEATION; MIXED CONDUCTION; ZIRCONIA; OXIDE; MICROSTRUCTURE
categoria
Chemistry; Electrochemistry; Physics
autores
Ivanova, D; Lima, EMCLGP; Kovalevsky, A; Figueiredo, FML; Kharton, VV; Marques, FMB
nossos autores
Andrei Kavaleuski
Investigador principal
Fernando Manuel Bico Marques
Professor Catedrático
Filipe Miguel H Lebre R Figueiredo
Investigador Principal
Vladislav Kharton
Investigador Principal Covidadoagradecimentos
Grants were provided by the Erasmus Mundus Joint Masters Programme, CEC-Brussels (D. Ivanova) and PRODEP Programme, Portugal (E. Gomes). Financial support from FCT (Portugal) and CEC-Brussels (NoE FAME) is greatly appreciated.