Study of the electrical conductivity of calcium sulfate dihydrate (CaSO4·2H2O) and its potential applications in electronics

Le résumé fourni par la source

This work is devoted to a comprehensive study of the structural and electrophysical properties of citrogypsum, a high-tonnage byproduct of biochemical citric acid production. Compacted test samples were fabricated via cold isostatic pressing. The chemical and phase compositions of the investigated anthropogenic raw material were determined using X-ray fluorescence and X-ray powder diffraction analyses. The surface morphology and textural characteristics were investigated by scanning electron microscopy and gas adsorption methods. The temperature dependence of the electrical conductivity of the samples was studied by broadband impedance spectroscopy in the frequency range of 200 Hz to 5 MHz under high vacuum conditions (10-3 mmHg) at temperatures of 250 K and 300 K using a Janis vacuum cryostat. It was established that at 300 K in the high-frequency region (330 kHz – 5 MHz), the complex impedance plot (Nyquist plot) is completely governed by the contribution of grain boundaries. The presence of two relaxation regions on the plot is attributed to the bimodal nature of the differential particle size distribution (~80 and ~500 μm), which is strictly confirmed by laser diffractometry data. Decreasing the temperature to 250 K leads to a transformation of the impedance profile in the low-frequency region (600 Hz – 1.1 kHz), manifested by the appearance of a linear diffusion contribution transitioning into a bulk transport arc; this behavior is successfully described by an equivalent circuit with a parallel combination of the grain bulk resistance (Rg) and capacitance parameter (Cg). The revealed features of electrical transport substantiate the potential of using modified citrogypsum matrices as functional dielectric media for the components of solid-state electronics.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.