Joining ceramic products made of magnesium and aluminum oxides is a difficult task due to the significant difference in the values of the coefficient of thermal expansion (CTE) of the materials. The actual difference in CTE of the articulated components is 5 · 10 K. In this paper, the possibility of using silicate glasses to connect ceramic products based on magnesium oxide and aluminum oxide is investigated, since the properties of glasses can be adapted to specific materials by selecting the appropriate components and their proportions. Glass-based sealants are cheap to manufacture, demonstrate acceptable stability in oxidizing and reducing environments, and have good adhesion and wettability. Four glass compositions with additives of alkali and alkaline earth metal oxides have been developed to combine ceramic products made of magnesium oxide and aluminum oxide. Their coefficient of thermal expansion, glass transition and softening temperatures are determined. The glass transition temperature is in the range of 458–613°C. The glass softening temperature ranged from 504°C to 687°C. The operating temperature of the ceramic joint is 650°C, so the glass must have a softening temperature (T) in the range 650–680°C. The glass sealant 930 and 6515 have a low softening temperature and cannot be used at an operating temperature of 650°C. Experimental gluing of samples from AlO and MgO using glasses 508 and 509 was carried out. The connection of ceramic parts made of aluminum oxide and magnesium using glass sealant 509 showed unsatisfactory results. It has been established that the hermetic connection of the articulated components is possible using glass sealant 508 with additives of alkali and alkaline earth metal oxides.
Nikonorova et al. (Wed,) studied this question.