Vitreous joining process of SiCf/SiC composites

The reactive joining of an SiCf-/SiC composite with a zinc borate glass was studied at various temperatures, in order to optimize the joining process and to fully understand the reactivity between glass and composite. A temperature-dependent gas-producing redox reaction between ZnO and SiC was found to give gradual disappearance of the bubbles and crystallites always present in the range from 700 to 1200 degrees C, and to yield a highly amorphous, bubble-free joint. This study permitted us to prepare single lap shear test specimens with minimal void content in the joint, i.e. a fully reacted and amorphous joint. The shear strength value obtained for these joints was higher than 15 MPa at room temperature. Copyright (C) 1996 Elsevier Science Ltd