Influence of the Nano- and Submicron Structure of Magnesium–Aluminosilicate Glasses on the Crack Resistance of High-Strength Glass-Ceramics

Abstract

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 glassceramic 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 magnesiumaluminosilicate glass is optimized by introducing a combined crystallization catalyst (ZrO 2 , TiO 2 , Sb 2 O 5 , ZnO, CeO 2 , P 2 O 5 ) 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), -cordierite (980-1050С) and recrystallization of -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 (MgO, Al 2 O 3 , SiO 2 ) is of 87.0 wt.%; type and content of crystallization catalysts (TiO 2 , ZrO 2 , СеО 2 , P 2 O 5 ) is of 8.0 wt.% and content of modifying additives (SrO, CaO, B 2 O 3 ) is of 5.0