VITREOUS JOINING PROCESS OF SICF SIC COMPOSITES/

The reactive joining of an SiCf-/SiC composite with a zinc borate glas s was studied at various temperatures, in order to optimize the joinin g process and to fully understand the reactivity between glass and com posite. A temperature-dependent gas-producing redox reaction between Z nO and SiC was found to give gradual disappearance of the bubbles and crystallites always present in the range from 700 to 1200 degrees C, a nd to yield a highly amorphous, bubble-free joint. This study permitte d us to prepare single lap shear test specimens with minimal void cont ent 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 roo m temperature. Copyright (C) 1996 Elsevier Science Ltd