Alumina Ceramics Joined With Screen-Printed B2o3 By Spark Plasma Sintering

The alumina ceramics were joined by spark plasma sintering (SPS) at 1000 degrees C for 10 min under an applied pressure of 30 MPa using the screen-printed B2O3 as the joining material. The thickness of the interlayers after joining was approximately 5 mu m. The average shear strength measured of the joint was 141.9 +/- 4.1 MPa, which was the highest value of joined alumina ceramic using B2O3 only ever reported in the open literatures. The presence of Al4B2O9 whiskers formed by the in-situ reaction between B2O3 and Al2O3 was assumed to contribute to the strong joint. A sample with extra holding at 400 degrees C for 10 min before 1000 degrees C was conducted to investigate the suppression effect of joining parameter on the volatilization of B2O3. The average shear strength was 104.2 +/- 9.4 MPa, which implied that low-temperature holding step promoted rather than suppressed B2O3 volatilization, resulting in lower shear strength.