Novel SnO2 ceramic surge absorbers for low voltage applications

• Single phase SnO2 varistor with coarse-grained microstructure obtained by Bi2O3 addition.
• Low breakdown field (0.5 kV/cm) and high nonlinearity (22) obtained for SnO2 varistor doped with 0.15 mol% Bi2O3.
• Low voltage SnO2 varistors exhibit a suitable surge-withstand capability.

To make SnO2–CoO–Nb2O5–Cr2O3–Y2O3–Bi2O3 ceramics suitable for low voltage varistor applications, the amount of Bi2O3 addition to a well-known SnO2-based composition for high voltage varistors was optimized. The addition of 0.15 mol% Bi2O3 has resulted in a single phase ceramic material with the average grain size of 30 μm and electrical properties useful for low voltage varistors. The obtained SnO2 low voltage varistors exhibit excellent electrical properties as surge absorbers.

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