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Synthesis, Sintering, and Microwave Dielectric Properties of KTaO 3 Ceramics
Author(s) -
Axelsson AnnaKarin,
Pan Yuya,
Valant Matjaz,
Alford Neil
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03130.x
Subject(s) - materials science , sintering , tetragonal crystal system , ceramic , dielectric , tungsten , potassium niobate , mineralogy , relative density , phase (matter) , dielectric loss , analytical chemistry (journal) , microwave , porosity , microstructure , composite material , ferroelectricity , metallurgy , chemistry , optoelectronics , physics , organic chemistry , chromatography , quantum mechanics
Studies of a synthesis of KTaO 3 displayed a two‐step reaction path with the intermediate formation of K 2 Ta 4 O 11 . Thermal and X‐ray diffraction analysis showed that the synthesis is completed at 900°C. Sintering studies showed that KTaO 3 powder can produce single phase ceramics with 85% of relative density with the addition of 5% of potassium excess when sintered at 1330°C for 1 h. Longer sintering times or higher temperatures result in enhanced potassium loss and consequent formation of K 6 Ta 10.8 O 30 secondary phase with tetragonal tungsten bronze structure. Room‐ and low‐temperature microwave dielectric properties of KTaO 3 ceramics compare well with measurements performed on single crystals. We evaluated the influence of microstructural features (porosity, structural defects, secondary phases) on the dielectric properties of the ceramic samples.