Fabrication of high Tc BaTiO3–Bi0.5Na0.5TiO3 positive temperature coefficient of resistivity ceramics using the sol–gelmethod
2013; Elsevier BV; Volume: 96; Linguagem: Inglês
10.1016/j.matlet.2013.01.052
ISSN1873-4979
AutoresHailong Li, De’an Yang, Yuanfang Qu,
Tópico(s)Multiferroics and related materials
ResumoBaTiO3–Bi0.5Na0.5TiO3 (BT–BNT) positive temperature coefficients of resistivity ceramics were successfully prepared by the sol–gel method. The synthesized fine and chemical homogeneous powders could decrease the volatilization of Bi2O3 and Na2O by lowering the sintering temperature. The effect of BNT content on Lg(ρmax/ρmin), the room temperature resistivity, the Curie temperature and the microstructure of the lead-free PTCR ceramics was studied. When BNT ≤4 mol%, the PTCR ceramics sintered at 1250 °C in air atmosphere displayed excellent PTC effect with a resistivity jump of 3–4 orders of magnitude. The room temperature resistivity and the Curie temperature of the sample with 5 mol% BNT were 4.46×106 Ω cm and 148 °C, respectively. However, when the BNT content exceeded 5 mol%, the ceramics displayed dielectric behavior.
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