| Summary: | 碩士 === 國立臺南大學 === 材料科學系碩士班 === 96 === This research is composed of two parts. First, the ceramics of Ag1-xLixNbO3（ALN） solid solution were sintered for Li concentration range 0≦x≦0.1. We investigate the phase transition behavior and dielectric properties of Li-doped with different concentration by using XRD、SEM、DSC、dielectric constant and Raman scattering. As a result, with increasing lithium contents, the phase transition of M1-M2 was shifted to lower temperature while the phase transition of M3-O1 was shifted to higher temperature. The orthorhombic symmetry was changed to tetragonal symmetry when x is greater than 0.05. The maximum value of the dielectric constant at x＝0.05 was 400, and the dielectric loss value was controlled below 5%. Second, the ceramics of Ag1-yBiy/3NbO3 solid solution were sintered for Bi concentration range 0≦y≦0.15. Using the same analytic instruments, we investigate the phase transition behavior and dielectric properties of Bi-doping with different concentration. Room and high temperature phase transition were shifted to lower temperature by Bi-doping. Phase transition points were shifted to become fast and the phase structure was changed toward tetragonal symmetry after y>0.15. In addition, the value of dielectric loss was controlled below 0.2% from 250K to 450K.
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