Microstructure and mechanical properties of SiC joint using anorthite based glass-ceramic and first principles calculation of joint interface

Abstract

A specialized CaO–Al2O3–SiO2 (CAS) glass-ceramic was innovated to join SiC ceramics. The crystallization kinetics of the CAS glass was studied, revealing distinct anorthite precipitates in the CAS glass-ceramic. The impact of process parameter variations on microstructure and mechanical properties was studied. It revealed that post-joining crystallization heat-treatment could change the size and the content of crystals and significantly improve the shear strength of the joint. It was duly observed that a remarkable shear strength of 86 MPa was achieved when the joint was formed at the temperature of 1450 °C and treated at 1050 °C for crystallization. Notably, this exceptional mechanical endurance remained impressively high, maintaining a value of 85 MPa at 800 °C. Based on density functional theory calculations, it was confirmed that glass/C–SiC (0001) has a stronger interface bond than glass/Si–SiC (0001), resulting in a reliable joining at the glass/C–SiC (0001) interface for CAS glass and SiC.