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Influence of Oxygen Substoichiometry on the Dielectric Properties of BaTiO 3‐δ Nanoceramics Obtained by Spark Plasma Sintering
Author(s) -
Voisin Christophe,
GuillemetFritsch Sophie,
Dufour Pascal,
Tenailleau Christophe,
Han Hyuksu,
Nino Juan C.
Publication year - 2013
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.12058
Subject(s) - spark plasma sintering , materials science , barium titanate , dielectric , ceramic , oxygen , sintering , annealing (glass) , ceramic capacitor , grain boundary , capacitor , chemical engineering , composite material , metallurgy , microstructure , optoelectronics , chemistry , electrical engineering , organic chemistry , voltage , engineering
Oxygen‐deficient BaTiO 3‐δ nanoceramics were prepared by spark plasma sintering. Partially reduced raw nanopowders led to unusual dielectric properties. A short postsintering treatment was performed to reach a high ε r /tan δ, which makes them attractive for industrial applications such as low‐frequency capacitors. Surprisingly, our ceramics also remained black even after annealing for 5 days at 850°C in air, indicating the presence of barriers against oxygen diffusion. This exceptional behavior in pure barium titanate was consistent with a core–shell structure made of semiconductive grains and insulating grain boundaries, due to the presence of Ti 3+ /Ti 4+ and oxygen vacancies.