Alumina ceramics joined with screen-printed B2O3 by spark plasma sintering

The alumina ceramics were joined by spark plasma sintering (SPS) at 1000 °C for 10 min under an applied pressure of 30 MPa using the screen-printed B 2 O 3 as the joining material. The thickness of the interlayers after joining was approximately 5 μm. The average shear strength measured of the joint was 141.9 ± 4.1 MPa, which was the highest value of joined alumina ceramic using B 2 O 3 only ever reported in the open literatures. The presence of Al 4 B 2 O 9 whiskers formed by the in-situ reaction between B 2 O 3 and Al 2 O 3 was assumed to contribute to the strong joint. A sample with extra holding at 400 °C for 10 min before 1000 °C was conducted to investigate the suppression effect of joining parameter on the volatilization of B 2 O 3 . The average shear strength was 104.2 ± 9.4 MPa, which implied that low-temperature holding step promoted rather than suppressed B 2 O 3 volatilization, resulting in lower shear strength.