Fabrication of high Tc BaTiO₃–Bi₀.₅Na₀.₅TiO₃ positive temperature coefficient of resistivity ceramics using the sol–gelmethod
2013
Li, Hailong | Yang, De'an | Qu, Yuanfang
BaTiO₃–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 ≤4mol%, 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 5mol% BNT were 4.46×10⁶Ωcm and 148°C, respectively. However, when the BNT content exceeded 5mol%, the ceramics displayed dielectric behavior.
显示更多 [+] 显示较少 [-]