Structural and electrical characterization of semiconducting barium-lead-titanate ceramics

BaTiO3 is usually doped to achieve the temperature stability required by de vice applications, as well as to obtain a large positive temperature coeffi cient anomaly of resistivity (PTCR). Uniform distribution of dopants among the submicron dielectric particles is the key for optimal control of grain size and microstructure to maintain a high reliability. The system Ba0.84Pb 0.16TiO3 was synthesized from high purity BaCO3, TiO2, PbO oxide powders as raw materials. Sb2O3, MnSO4 and ZnO were used as dopants and Al2O3, TiO2 a nd SiO2 as grain growth controllers. Phase composition was analyzed by usin g XRD and the microstructure was investigated by SEM. EDS attached to SEM w as used to analyze phase composition specially related to abnormal grain gr owth. Electrical resistivities were measured as a function of temperature a nd the PTCR effect characterized by an abrupt increase on resistivity.