Role of initial potassium excess on the properties of potassium tantalate ceramics

• Tipo: Artigo em Revista Científica Internacional
• Data: 2011

Autores

Tkach, A (Autor) Outra; Vilarinho, PM (Autor) Outra; Almeida, A (Autor) FCUP

Revista

Título: Journal of the European Ceramic Society

Vol. 31

Páginas: 2303-2308

ISSN: 0955-2219

Editora: Elsevier

Indexação

ISI Web of Knowledge - 5 Citações

Scopus - 5 Citações

Outras Informações

ID Authenticus: P-002-KCV

DOI: 10.1016/j.jeurceramsoc.2011.06.012

Abstract (EN): Potassium tantalate (KTaO(3) - KT) ceramics with controlled initial K/Ta ratio=1, 1.02 and 1.05 were synthesised by solid-state reaction. Crystal structure and microstructure of the sintered ceramics were examined by XRD and SEM/EDS, respectively. Their dielectric properties were then studied as a function of the temperature over the radio frequency range. Ceramics with K/Ta ratio=1 exhibits potassium-poor secondary phases, in contrast to ceramics with initial K/Ta ratio = 1.05, where no secondary phases are detected. Moreover, the grain size increases dramatically with K/Ta ratio >1. The quantum paraelectric behaviour of KT ceramics is weakly affected by the variation of K/Ta ratio and their dielectric response is well described by Barrett's equation. Though, no anomaly is induced in the dielectric permittivity by potassium excess, it yields an increase of its lowest temperature magnitude up to similar to 4000, which is to the best of our knowledge, the highest value ever reported for KT ceramics.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6