Studies on grain-boundary chemistry of perovskite ceramics as CO gas sensors

The sensing phenomena and mechanism of ceramic chemical sensors are based on the chemical defect structure and its behavior in environmental atmospheres. The surfaces of the grain boundaries act as a uniform source and sink for vacancies, and the lattice defects play a positive role for the sensing effect in the perovskite ceramics. The role of defects in an environmental atmosphere of CO gas for La doped BaTiO3 based PTCR ceramics is investigated. (C) 2003 Elsevier Science B.V. All rights reserved.