Fabrication of Lead-Free Semiconducting Ceramics Using BaTiO₃-(Bi_1/2Na_1/2)TiO₃ System by Sintering in Air Atmosphere

Abstract:

BaTiO₃–(Bi_1/2Na1/2)TiO₃ (abbreviated as BT-BNT) solid solution ceramics, as a lead-free PTC (Positive Temperature Coefficient of resistivity) thermistor material usable over 130°C, were synthesized in air atmosphere. By conventional processes, La-doping was not effective in giving semiconducting property to the BT-BNT ceramics because of volatilization of sodium and bismuth during sintering. By preventing the volatilization by lowering the sintering temperature using very fine TiO₂ powder and by adding calcium oxide to calcined BT-BNT powders, we obtained BT-BNT semiconducting ceramics which shows a resistivity change near Curie temperature.

• Periodical: Key Engineering Materials (Volume 485)
• Pages: 245-248
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.485.245
• Online since: July 2011
• Authors: Takashi Tateishi, Han Joong Sang, Hiroaki Takeda, Takuya Hoshina, Spela Kunej, Takaaki Tsurumi
• Keywords: Barium Titanate (BT), Bismuth Sodium Titanate, Lead-Free, Semiconducting Ceramics

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