Sintering and dielectric behavior for doped cordierite by xCuO within MgO (1-x)–Al2O3–SiO2 ceramics

Abstract

Crystalline structure, morphology, quantitative chemical constitution and dielectric properties of pure cordierite ceramic (CC) bodies and these doped with xCuO in formula MgO(1-x)Al2O3SiO2 (x = 0, 0.02, 0.04 and 0.06 wt%), prepared by a conventional solid state ceramic process, were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray fluorescence (XRF) and broadband dielectric spectrometer (BDS), respectively. Experimental results showed that doping with CuO results in lowering sintering temperature, lowering porosity, increasing bulk density and formation of copper magnesium silicate (CuMgSi2O) phase. CuMgSi2O which was formed with the highest content of CuO (0.06 wt %) increases the glassy phase, i.e. crystalline phase decreases of CC. Accordingly, the dielectric properties of CC found to be affected by CuO content. For instance, the permittivity and loss tangent slightly increased upon doping with 0.02 wt % CuO and then considerably decreased for sample doped with 0.06 wt % CuO due to formation of CuMgSi2O phase. Particularly, the loss tangent attained much lower values (0.003 at 25 °C) upon doping with 0.06 wt% CuO. Interestingly, such materials of very low loss can be used as candidates for wireless communication systems as well as in several electronic devices.