Abstract
In this work net-donor doped barium titanate ceramics were studied with impedance spectroscopy in the temperature range of 50 – 400 °C, SEM-EDX, XRD and TG-MS. A modified solid oxide route was applied to synthesize disk like ceramic samples showing a micro-scale microstructure and the PTCR-effect. PTCR-curves were measured with impedance spectroscopy, which led to a good separation of bulk-resistivities, grain boundary-resistivities and grain boundary capacitances. A variation of the DC-bias and the AC-amplitude showed the dependence of the electrical resistance of the samples on the applied electric field. Impedance spectroscopy was also applied on industrial PTCR ceramic samples. A variation of DC-bias, AC-amplitude, geometry, sinter-parameters, pO2 and reduction-oxidation experiments led to further insight to the characteristics of the material. The last part of the work dealt with the synthesis of submicron ceramic samples via a nanoscale precursor obtained by an oxalate precipitation route and low temperature calcination. This product was characterized in a temperature range of 50 – 400 °C. No PTCR-effect could be found in this oxalate-precursor product. However, the trapping energy for the Manganese dopant could be determined.
Translated title of the contribution | Synthese, Struktur und Elektrische Eigenschaften von Donor Dotierten Bariumtitanat Keramiken |
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Original language | English |
Qualification | Dr.mont. |
Supervisors/Advisors |
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Publication status | Published - 2016 |
Bibliographical note
no embargoKeywords
- Donor doped barium titanate
- Impedance spectroscopy
- PTC-effect
- Interfacially controlled electroceramics
- Grain boundaries
- Electrical properties
- Nanosynthesis
- Oxalate route
- Solid oxid route