2011 Volume 119 Issue 1395 Pages 828-831
BaTiO3–(Bi1/2Na1/2)TiO3 (abbreviated as BT–BNT) solid solution semiconducting ceramics, as a candidate for a lead-free PTC (Positive Temperature Coefficient of resistivity) thermistor usable over 130°C, were synthesized by adding CaO into the calcined powder. The CaO added BT–BNT ceramics showed semiconducting behavior with the resistivity at room temperature ρRT = 103 Ω cm and a resistivity change near Curie temperature. Chemical composition analysis suggested that Ca2+ acted as a donor by substituting for Na+ in the BT–BNT ceramics.