In this study, the effect of Nb2O5 and sintering time on the positive temperature of coefficient of resistivity (PTCR) behavior of lead free Ba0.99(Bi0.5Na0.5)0.01TiO3 (BBNT) ceramics were investigated in order to fabricate a PTC thermistor with high Tc temperature more than 140℃. In particular, BBNT ceramic doped with 0.1mol% Nb2O5 and sintered at 1350℃ for 4 h has significantly increased Curie temperature (Tc) of about 200℃, showed good PTCR behavior of room-temperature resistivity (ρrt) of 40 Ω·㎝, a high ρmax/ρmin ratio of 43.78×103 and a large resistivity temperature factor (α) of 16.1%/℃. With increasing addition of Nb2O5 content, the ρrt decreased to a minimum value of 40 Ω·㎝ at 0.1mol% Nb2O5 and the ρrt increased for x value over 0.1 mol%.
