%0 Journal Article
%A Löhnert, Romy
%A Schmidt, Rainer
%A Töpfer, Jörg
%T Effect of sintering conditions on microstructure and dielectric properties of CaCu3Ti4O12 (CCTO) ceramics
%D 2015
%@ 1385-3449
%U https://hdl.handle.net/20.500.14352/24315
%X The influence of sintering temperature and dwell time on the microstructure formation and dielectric properties of CaCu_(3)Ti_(4)O_(12) ceramics was investigated. For sintering temperatures of 1050 and 1100 °C significant differences in the CaCu_(3)Ti_(4)O_(12) ceramic microstructure and the segregation of a CuO_(x)-rich phase towards the grain boundary (GB) areas were observed with increasing dwell time. In addition to the formation of a semiconducting bulk and insulating grain boundary phase the segregated CuO_(x) forms an intergranular phase, and the effects of this phase on the dielectric properties are rather intriguing. At sintering temperature below 1050 °C only small amounts of CuO_(x) segregate, whereas sintering above 1050 °C (e.g., 1100 °C) leads to increased evaporation of the CuO_(x). Therefore, the effects of the CuOx-rich intergranular phase upon the dielectric properties are felt strongest in samples sintered at 1050 °C. Such effects are discussed in terms of microstructural variations due to liquid phase sintering behavior facilitated by the TiO_(2)-CuO_(x)-eutectic, which appearsto be melted at high sintering temperature prior to evaporation of CuO_(x) at prolonged dwell times at the highest sintering temperatures(1100 °C).
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