MICROANALYSIS ON FUNCTIONAL CERAMICS: COMPLEMENTARY INVESTIGATION TECHNIQUES ON ZnO-BASED VARISTOR CERAMICS

摘要

ZnO-based varistor ceramics exhibit exceptionally high non-linear current-voltage characteristics caused by so-called double Schottky barriers at the grain boundaries. There are many influencing quantities on the properties of these potential barriers, which are responsible for the behaviour of whole components. Combined electrical and microstructural analyses were performed on Pr-doped ZnO samples to find the main correlation factors for the height of potential barriers in a ceramic microstructure. Modelling the material on a micromechanical approach supports the interpretation of the experimental findings.