GLASS FORMATION AND PROPERTIES OF CORDIERITE COMPOSITIONS FROM TALC-BASED NATURAL RAW MATERIALS WITH BORON OXIDE ADDITION

In this study, the glass forming behaviour of cordierite compositions in MAS (MgO-Al2O3-SiO2) system with added B2O3 content up to 3% were studied by melting the natural raw materials such as; talc, kaolin, alumina and boric acid as the source of MgO, SiO2, Al2O3 and B2O3 respectively. XRD analysis revealed the glass formation. Optical properties of the glasses were measured using UV-VIS spectrophotometer and structural changes were monitored by using FT-IR spectrometer. Physical properties such as density, colour, thermal expansion coefficients and hardness were measured according to the standard test methods. Glasses with a green colour were produced and this was attributed to the Fe content in the glass up to 0.5% coming from talc and kaolin. The addition of B2O3 to the glasses increased the glass transition temperatures (Tg) values and reduced the thermal expansion coefficient values of the glasses from 5.2226 to 5.0072oCx10-6, for MAS-T-0 and MAS-T-3, respectively.