Vapor Doping Method, a New Effective Method Used in BaTiO_3 Based PTCR Ceramics

Grain boundary effect is one of the characteristics of ceramic materials. Some oxides have high vaporization pressure. Using vapor as doping resource during sintering, the grain boundary behavior can be effectively controlled and the material properties can be improved. The PTCR effect that existed in semiconducting barium titanate based ceramics is a typical grain boundary effect. The experimental results show that materials doped with Sb2O3 or Bi2O3 vapor have high density and homogeneous microstructure with small grain size. The sample with over 8 orders of magnitude degree of resistivity jumping can be obtained. Thus vapor doping method is a new and effective method.