Structural, dielectric and electrical characterization of (Co)x(Ni/bentonite) composites

Abstract

Based on commercial bentonite (bento) and two metal precursors, including NiCl2 and CoCl2, diverse series of composites were prepared by incipient wet impregnation. The prepared composites were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-Ray spectroscopy. X-ray diffraction studies show that the crystallite size decreased as increasing the wt. % of cobalt. Moreover, the presence of Co in the EDX spectra for all bento concentrations, suggests its successful incorporation and probably the formation of Ni–Co oxide. The dielectric constant ε′, the dielectric modulus (M′, M′′) and the ac conductivity (σac) were also studied. It was found that ε′ decreases with frequency in all samples, a clear dielectric α relaxation observed from dielectric loss M′′. σac decreases by increasing Co content and the conduction mechanism is correlated barrier hopping (CBH). σac(T) is thermally activated and the activation energy Ea decreased with increasing Co content.

Keywords

• bentonite
• ni–co
• dielectric properties
• conductivity