Dielectric Properties of Basaltic Glass and Glass-Ceramics: Modeling and Applications as Insulators and Semiconductors

Abstract

Sinai basaltic rocks were melted as glass and casted into disc- and rode-shapes and subjected to thermal treatment to induce crystallization as a glass-ceramic. The dominant crystalline phases were assigned as diopside, with some amounts of anorthite and magnetite crystals. Different techniques were used in that study such as differential thermal analysis, X-ray diffraction, SEM and dielectric properties (dielectric constant and loss beside to the electric conductivity). Glass-ceramic samples that were thermally treated at low temperatures (850 ∘ C) gives surface crystalline and coarse-grained textures, while glass-ceramic samples treated at relatively higher temperatures (1000 ∘C) introduced volume crystalline and fine-grained textures. The dielectric constant (e′) was measured at 1000 points in the frequency range 42 Hz up to 8MHz. It decreases with increasing the applied frequency and decreases with increasing the crystallization degree, where it varies between 9.99 at 42 Hz and 7.61 at 8 MHz. The dielectric loss values are relatively low (0.68 at 42 Hz down to 0.03 at 8 MHz), whereas the electric conductivity (σ) values refer to insulator materials (σ < 10− 8 S/m) at low electric frequencies at 42 Hz and to semiconductor materials at high electric frequencies at 8 MHz (10− 8 <σ < 103 S/m). The results show that the glass-ceramic can be used in low dielectric materials in the electronics covering industry.