Ceramic Matrix Composites (CMCs) are high-temperature and corrosive-resistant materials with excellent thermo-mechanical properties in extreme production conditions. The EU CEM-WAVE project (G.A. 958170) will develop CMCs to be used in radiant tube furnaces for the steelmaking industry. This work focuses on the joining process of oxide/oxide ceramic matrix composites (Al₂O_3f /Al₂O₃-ZrO₂), which are distinguished by their intrinsic oxidation resistance and good thermal shock resistance. The main requirements for their use as radiant tube furnace components come from the extreme operating conditions such as high temperatures, corrosive environment, high levels of humidity, and flame exposure.
Two Y₂Ti₂O₇ based glass-ceramics systems are proposed as joining materials with specific and optimized properties to withstand severe operating conditions, including temperatures up to 900 °C. Their compositions are formulated, fulfilling criteria of wettability, coefficient of thermal expansion matching and thermomechanical compatibility with the oxide/oxide CMC. The joints showed an apparent higher shear strength than the interlaminar shear strength of the composites, which led to failure of the composites during the single-lap offset tests.
Excellent adhesion of the glass-ceramics to the CMC substrate, as well as no microstructural changes in the glass-ceramic seal, were observed after direct flame exposure with a 900 °C flame and thermal cycling between 400 °C and 900 °C.
The research carried out to write this article was funded under the CEM-WAVE project. This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 958170. This document only reflects the authors’ view. The European Commission is not responsible for any use that may be made of the information it contains.