Processing of glass-ceramics in the SiO2–Al2O3–B2O3–MgO–CaO–Na2O–(P2O5)–F system via sintering and crystallization of glass powder compacts

Glass-ceramics were produced by crystallization of glasses in the SiO2–Al2O3–B2O3–MgO–CaO–Na2O–F system. The experimental results showed that bulk glasses are prone to surface crystallization. Hence, crystallization of bulk glasses resulted in non-homogeneous crystalline materials, which comprised relatively coarse crystals. Therefore, processing was realized using glass-powder compacts. Maximum densification was reached at 700–750 °C. This interval is positioned at relatively lower temperatures than those often reported for similar sintered glass-ceramics. Doping with P2O5 improved sintering behaviour and broadened sintering temperature range. Sintering between 750 and 800 °C resulted in materials, which exhibited dense crystalline microstructure and the maximum flexural strength.