Effects of Dy2O3 on the Electrical Properties of a (Nb2O5-Dy2O3-SiO2) Co-doped TiO2 Varistor

Rutile-TiO2 ceramics are very promising electronic ceramic materials which can be applied in varistors because of their good electrical properties. In this work, Dy2O3 was used to improve the properties a TiO2 varistor doped with 0.60 mol.% Nb2O5 and 0.30 SiO2. Results showed that possessed optimal nonlinear coefficient ( $$ \alpha = 5.7 ), low breakdown voltage E_{\text{B}} 1.34\;{\text{V}}\,{\text{mm}}^{ - 1} ) colossal dielectric constant \varepsilon_{\text{r}} 8.01 \times 10^{5} ). The microstructural analysis after incorporation into varistor, grains tended more semiconducting due defect carriers derived from substitution Dy3+ for Ti4+. Meanwhile, moderate dopant also increased grain size narrow boundary. Consequently, decreased, while improved.