| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === Pb(Fe2/3W1/3)O3(PFW) is one of the classic relaxors, with the phase transition temperature of -90℃. Since the phase transition temperature of the PbTiO3-PT is 490℃, the phase transition temperature can be adjusted to higher temperature in need by increasing the x ratio for the (1-x)PFW-xPT solid solution.
In present work, the (1-x)PFW-xPT relaxor system is synthesized with the conventional solid solution. The dielectric loss decreases and the dielectric diffusion property increases as doping the dopant MnO for the (1-x)PFW-xPT. Although, the broader peak dielectric constant is obtained as doping MnO, the improvement is not sufficient for the application of capacitor. A great improvement on the temperature dependence of the dielectric constant has been done by using the temperature-compensation method, where the two-layer-structure capacitor is stacked with two heterogeneous dielectric materials of 0.8PFW-0.2PT-0.15w%MnO and 0.7PFW-0.3PT-0.15w%MnO ceramics.
According to the experimental results, the very lower dielectric loss is observed as doping 0.15w% MnO. The smoothest dielectric constant in the temperature range between -10℃ and 40℃ has been accomplished for the two-layer-structure capacitor with the weight ratio of 2:1 the0.8PFW-0.2PT-0.15w%MnO and the 0.7PFW-0.3PT-0.15w%MnO.
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