Ceramics-Silikáty 53, (3) 171 - 179 (2009)

The crystallization behaviour of some glasses in the CaO–ZnO–Al₂O₃–SiO₂ system was investigated using different heattreatment parameters. Cr₂O₃ and CaF₂ were used as nucleating agents. Differential thermal analysis, X-ray diffraction, dilatometry and scanning electron microscopy were used in this study. Melilite, α- and β-willemite, anorthite, wollastonite, pseudowollastonite and petedunnite phases developed in the investigated glasses. The formation of compatible and incompatible phase assemblages and the effect of Cr₂O₃ and CaF₂ are illustrated. Glass-ceramics with fine-grained microstructures and CTE values ranging from 36 to 73 × 10⁻⁷ K⁻¹ in the 20-700°C range were obtained.