Thermal and Mechanical Properties of Glass-Ceramics Based on Slate and Natural Raw Materials

In recent years, utilization of raw materials was increased to produce natural low-cost glass-ceramic materials with distinct properties and appropriate for various applications. Therefore, five glass-ceramic samples were prepared using slate and natural raw materials known as limestone, dolomite and silica sand. Sample batches were melted in an electric furnace at temperatures between 1500 and 1550 degrees C for 2-3 h, casted, and heat-treated at 1100 degrees C for 2 h based on the results of differential thermal analysis to induce crystallization. The obtained samples of glass-ceramic were studied using X-ray diffraction, scanning electron microscopy, microhardness and bending strength testing, and thermal expansion analysis. It was found that the glass-ceramic samples mainly comprised of beta- wollastonite, diopside, and anorthite with ultra-fine grains and uniform textures. Furthermore, the fabricated glass-ceramic samples possessed high hardness values ranging from 9720 to 10,052 MPa, bending strengths between 97 and 142 MPa, and thermal expansion coefficients varying from 84.54 x 10(-7) to 68.53 x 10(-7) degrees C-1 in the range of temperature 20-800 degrees C. Thus, the good mechanical properties and thermal expansion coefficients of these natural glass-ceramic samples make them promising and suitable for many civil, engineering and industrial applications.