Role of oxygen at the grain boundary of metal oxide varistors: A potential barrier formation mechanism

• DOI: 10.1063/1.1378051
• Publication Date: 2002-07-26T13:26:45Z
• Authors: P. R. Bueno; E. R. Leite; M. M. Oliveira; M. O. Orlandi; E. Longo
• Keywords: Varistor

A model is proposed here to explain how the chemical features of metal oxide varistors can alter their nonohmic physical behavior, based on similarities in electrical properties ZnO- and SnO2-based varistors. The explains before after thermal treatments oxygen- nitrogen-rich atmospheres, which cause similar changes feature these polycrystalline ceramics with greatly differing compositions microstructures. key role that oxygen plays varistor grain boundaries, independently type ceramic system (ZnO-, SnO2- or even SrTiO3-based varistors) involved.