A general strategy towards improving the strength and thermal shock resistance of glass-ceramics through microstructure regulation

Glass-ceramics are usually obtained through controlled crystallization. In this work, we propose a new strategy to add an appropriate amount of oxide particles to the parent glass to improve the performance of glass-ceramics. Different amounts of Al₂O₃ or/and CeO₂ particles were added into a SiO₂-Al₂O₃-ZnO-CaO-ZrO₂-TiO₂ based glass, and crystallization behavior, fracture strength, and thermal shock behavior were systematically evaluated. The results indicate that with the addition of Al₂O₃ or/and CeO₂ particles of moderate amount, the unfavorable needle-like ZrSiO₄, Zn₂SiO₄, and CaTiSiO₅ crystals were largely inhibited when annealed at 900 °C. Accordingly, fracture strength is maintained high after heating at high temperatures. The thermal shock resistance is also enhanced drastically. The additive Al₂O₃ is thermodynamically favorable to react with the glass, forming particulate ZnAl₂O₄ instead of precipitating the needle-like crystals of Zn₂SiO₄ and CaTiSiO₅; while CeO₂ will combine with ZrO₂ to form a solid solution and promote the precipitation of primary crystal CaZrTi₂O₇ that will not transform to ZrSiO₄ with prolonging thermal exposure.