Abstract:

In order to investigate the effect of CIγstal defect on the electrical properties of ceramics in a microcosmic scale , BaPbO₃ and BaTiO₃ polycrystalline ceramics were used as two objects to investigate the relationship between their conductive properties and crystal defect structures by studying the defect structure and roonHemperature conductivity of the ceramics sintered in different firing atmospheres. The results show that the difference in electrical properties between BaPbO₃ and BaTiO₃ ceramics mainly results from the difference in the defect structure. As the BaPbO₃ sample is of a shallow acceptor energy level , high conductivity can be achieved after sintering in oxidizing condition because the cavities trapped in the acceptor center are easy to transit to the valence band to form conductive carriers. However , the BaTi03 sample with a deep acceptor energy level turns into an insulator after sintering in oxidizing condition.

Key words: barium plumbate, barium titanate, defect structure, conductivity