Electrical, Microstructural and Physical characteristics of talc-based cordierite ceramics

Abstract

The aim of this work is to study the effect of various talc rocks for the preparation of talc-based cordierite ceramics. Raw talc and sintered cordierite-based ceramic samples (1000-1375ºC for 2h) were characterized using XRD, XRF, TGA-DTG, laser PSDs, Archimedes method, SEM-EDAX and dielectric relaxation spectrometer (DRS). Results show that impurity oxide contents, particle size and mineralogical changes of green batches influenced the microstructure densification and crystallization of orthorhombic and hexagonal cordierite. The complex electric modulus plot shows the existence of two relaxation processes associated with the capacitive contribution grain boundaries and grain at low and high frequencies, respectively. The dielectric loss reached much lower values (0.0004-0.0007) for the ceramics composed of higher cordierite phase composition (87.00 to 92.00wt.%) that sintered at 1350 and 1375ºC. Such ceramics could be promising in electronic applications like capacitors, microwave devices and wireless communication.