Effects of chemical compositions of adhesive and joining processes on bondstrength of Si3N4/Si3N4 joints

Silicon nitride ceramics were pressurelessly joined using glass adhesives w ith different alpha-Si3N4 powder additions at the temperatures ranging from 1450 to 1750 degrees C for 10-120 min. The bond strength of the joint decr eased sharply with increasing alpha-Si3N4 content in the adhesive. An optim um strength, 400 MPa, was obtained when joining was performed at 1650 degre es C for 30 min. The results of the microstructural analysis showed that an intimate and glass-filled bond was produced where thermal cracks were also found clearly. (C) 1999 Elsevier Science Limited and Techna S.r.l. All rig hts reserved.