Papers by Keyword: Zr-Doped

Abstract: Zr_xNi_1-xO was prepared by conventional solid state reaction. The properties of undoped and ZrO₂ doped NiO ceramics have been studied. The raw mixture of ZrO₂ and NiO were ball milled for 24 hours. The samples were calcined at 1000°C for 2 hours, pressed into pellet shape at 200 MPa and sintered at 1300°C for 10 hours. The sintered samples were subjected to XRD, Scanning Electron Microscopy (SEM) and Impedance Analyzer for phase identification, microstructural observation and dielectric analysis. The grains size decrease with the increment of dopant amount. Enhanced dielectric constant was observed in the ZrO₂ doped NiO with x= 0.02 for the frequency range from 1MHz to 1GHz. The dielectric constant of sintered Zr_xNi_1-xO decreased with an increasing frequency. The result indicates that Zr ions have effectively changed the dielectric properties of NiO.Keywords: NiO, Zr-doped, XRD, SEM, Dielectric.

Abstract: CaCu3(Ti1-xZrx)O12 ceramics (x = 0.02, 0.04, 0.06, 0.08) were prepared by the conventional solid-state reaction method. Phase compositions, microstructure and dielectric properties were examined by XRD, SEM and impedance spectroscopy, respectively. The experimental results indicated that there is no obvious effect on microstructure characteristic by substituting Zr4+ for Ti4+. It was found that the values of the dielectric constant for all of the samples dropped into the order of 102, which is significantly lower than the order of 105 that of normally reported in the literature. It was suggested that the presence of impurity phases played an important role for the degeneracy of dielectric properties.