Effect Of Donor And Na_0.5Bi_0.5TiO₃（NBT） Dopants On Element’s Curie Temperature Of PTCR

Effect of donor Nb, La and Y and Na0.5Bi0.5TiO3(NBT) dopants on element’sCurie temperature during PTCR fabricating procedure was discussed in this study.Appropriateddoping mole ratio of Nb2O5is0.118%—0.144%and element’s Curietemperature showed a decrease(112℃+2℃) with increase of Nb addition.Appropriateddoping mole ratio of La2O3is0.097%—0.160%and element’s Curietemperature showed a decrease(96℃+2℃) with increase of La addition. Appropriatedoping mole ratio of Y2O3is0.140%—0.191%and element’s Curie temperature showeda increase(125℃+2℃) with increase of Y addition. Meanwhile, all the Nb, La orY-doped elements are well semi-conducted. Furthermore, the dependence of resistivityat room temperature with doping mole concentration for all the Nb, La or Y-dopedelements exhibit U-type curve.In comparison with the Curie temperature of the basic formula, addition of NBTwithout pre-sintering could improve element’s Curie temperature by20℃, and theaddition of NBT after pre-sinter could improve element’s Curie temperature by24℃.Meanwhile, the addition of NBT with pre-sinter or without pre-sinter could bothincrease elements’ resistivity at room temperature. The function of NBT after pre-sintercould be concentrated in grain boundaries and performed higher Curie temperature shiftefficiency than adding NBT before pre-sinter.