Abstract: 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.

Key words: vapor doping, BaTiO₃, PTCR