Lead-free high-temperature barium titanate-based PTCR ceramics and its electrical properties

The (1−x)BaTiO3-x{Na,K}0.5Bi0.5TiO3 solid solutions have been synthesized by solid-state reaction technique. The parameters of the crystal structure of the ceramic samples were determined by means of Rietveld full-profile X-ray analysis. With increasing x, the values of ρmax and ρmin increase due to the growth of potential barrier at grain boundaries. It has been found that in (1−x)BaTiO3-x{Na,K}0.5Bi0.5TiO3 system the grain boundary and the outer layer region make a contribution to the PTCR effect.