Enstatite–celsian glass ceramics

Celsian–enstatite-containing glass ceramic was prepared from Egyptian talc to be used as a substrate for magnetic storage media. The phase mixture was produced in a one-step heat treatment of 1200 °C. Celsian and hexacelsian phases are found in two of three experimental mixtures. Due to the effect of B2O3 in decreasing the viscosity of the glass, these phases did not form in the third mixture. TiO2 and ZrO2 insure adequate nucleation and improve the glass stability in the current MgO-containing talc. The thermal expansion coefficient is found to be between 50 and 80 × 10− 7/°C. The hexacelsian phase has rounded grains of less than 1 μm. Celsian grains have well-developed faces and a grain size in the range of 1–2 μm.