resumo
High quality factor and a temperature stable resonant frequency make BaLa4Ti4O15 (BLT) ceramics attractive materials for microwave applications. Aiming to exploit the effects of external stresses on the development of textured and anisotropic microstructures to optimise MW properties, the influence of applied external pressure during sintering of BLT ceramics is analysed. HRTEM and geometric phase analysis (GPA) showed that stresses applied during sintering, trigger the nucleation and growth of faults hypothesised to be due to the errors in the AO(3) layer (basal plane) stacking sequence of the hexagonal perovskite structure. The results reveal a strong correlation between the high concentration of structural defects and the development of anisotropic microstructures, which tune the properties of BLT. Stresses applied during sintering are therefore a promising tool to design material properties.
palavras-chave
STRONTIUM-TITANATE; GRAIN-GROWTH; IMAGES; ALUMINA
categoria
Materials Science; Metallurgy & Metallurgical Engineering
autores
Selvaraj, NB; Fernandes, M; Reaney, IM; Abrantes, JCC; Denneulin, T; Snoeck, E; Vilarinho, PM; Senos, AM
nossos autores
Ana Maria de Oliveira e Rocha Senos
Colaborador
João Carlos de Castro Abrantes
Professor Adjunto
Manuela Alexandra Coelho Fernandes
Estudante de doutoramento
Nivas Babu Selvaraj
Bolseiro de pós-Doutoramento
Paula Maria Lousada Silveirinha Vilarinho
Vice-DiretorGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
agradecimentos
The authors acknowledge Fundacao para a Ciencia e a Tecnologia (FCT), Fundo Europeu de Desenvolvimento Regional Portugal (FEDER), QREN-COMPETE Portugal, the Associate Laboratory CICECO (PEst-C/CTM/LA0011/2013) for funding support. NBS acknowledges FCT for financial support (SFRH/BPD/82158/2011). The authors acknowledge the support of European Union seventh framework programme under a contract for an integrated infrastructure initiative (312483-ESTEEM2).