Central Glass and Ceramic Research Institute, Khurja Centre, Khurja-203 131, UP, India
Department of Material Science, Jadavpur University, Calcutta-700 032, India
Abstract:
Both quartz and feldspar were progressively replaced by ground sillimanite sand and glass-ceramics in a classical porcelain composition and the effect of these replacements on the vitrification behaviour and mechanical and thermal properties in relation to the microstructure of specimens has been investigated. Progressive additions of sillimanite sand and crystallising glasses leading to the complete replacement of quartz and feldspar increased the strength, toughness and modulus significantly, and drastically reduced the per cent thermal expansion in the composition. The improvement in the properties is attributed to dramatic changes in the microstructural features as a result of significant reduction in the content of glassy phase and the simultaneous increase in crystalline phases such as mullite, sillimanite and cordierite.