Glass-ceramics for joining oxide-based ceramic matrix composites (Al2O3/Al2O3-ZrO2) operating under direct flame exposure

This work focuses on the joining processes of oxide-based ceramic matrix composites (Al2O3f /Al2O3-ZrO2), which are used as radiant tube furnace components in the steel industry. These components have to operate in harsh environments, and under high temperatures, and they therefore have to resist corrosion, humidity, and combustion. Two glass-ceramics systems, which have Y2Ti2O7 as their main crystalline phase, as well as specific and optimized properties to withstand severe operating conditions, including temperatures of 900 ◦C, are here proposed as joining materials. The adhesion of the glass-ceramics to the composite was found to be excellent after mechanical and thermal tests in which they were in direct contact with a 900 ◦C flame and thermal cycling of between 400 ◦C and 900 ◦C.