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O. V. Savvova, H. K. Voronov, O. I. Fesenko, V. D. Tymofieiev, and О. І. Pylypenko
Influence of the Nano- and Submicron Structure of Magnesium–Aluminosilicate Glasses on the Crack Resistance of High-Strength Glass-Ceramics
0667–0681 (2022)

PACS numbers: 61.43.Fs, 64.70.ph, 64.75.Lm, 68.37.Hk, 81.05.Je, 81.05.Pj, 81.40.Np

The main directions of the development of glass-ceramic materials for technical purposes, which are distinguished by a complex of high physicochemical, technological and operational properties, reduced cost and can be obtained using energy-saving and resource-saving technologies, are analysed. A detailed analysis of the state of development of cordierite glass-ceramic materials and the principles of their design made it possible to establish the possibility of developing high-strength materials on their base characterized by the formation of a dissipative nanostructure in the process of directed crystallization. The composition of magnesium–aluminosilicate glass is optimized by introducing a combined crystallization catalyst (ZrO₂, TiO₂, Sb₂O₅, ZnO, CeO₂, P₂O₅) to ensure the nucleation process and the formation of crystalline phases in the low-temperature range as well as the formation of a sitalized structure of a glass-ceramic material by the phase separation mechanism. As found, ensuring phase separation (800–850°С) by the spinodal mechanism for experimental magnesium–aluminosilicate glass in the pre-crystallization period is an important stage in the formation of solid solutions with a high-temperature quartz structure in the low-temperature region (850–900°С), spinel crystallization (900–1000°С), α-cordierite (980–1050°С) and recrystallization of α-cordierite to mullite at 1050–1100°С. The main conditions for the formation of a self-organized sitalized nano- and submicron structure of glass-ceramic materials based on mullite are determined as follow: the content of phase-forming oxides Σ(MgO, Al₂O₃, SiO₂) is of 87.0 wt.%; type and content of crystallization catalysts Σ(TiO₂, ZrO₂, СеО₂, P₂O₅) is of 8.0 wt.% and content of modifying additives Σ(SrO, CaO, B₂O₃) is of 5.0 wt.%; low-temperature synthesis and three-stage heat treatment (melting at 1550°C, 6 h; I stage at 800°C, 2 h; II stage at 900°C, 2 h; III stage at 1100°C, 1 h). As established, ensuring a high index of crack resistance (K_1C = 6.5 MPa·m^1/2), Young’s modulus of elasticity (E = 350 GPa) and low weight (ρ = 2800 kg/m³) simplifies the technology by reducing the temperature and allows it to compete successfully with cost-effective ceramic counterparts.

Key words: glass-ceramic materials, magnesium–aluminosilicate glasses, phase separation, cordierite, mullite.

https://doi.org/10.15407/nnn.20.03.667