Joining of Al2O3 to ZTA using a B2O3–Al2O3–SiO2 glass with in-situ precipitated whiskers

Abstract A novel B2O3–Al2O3–SiO2 (BAS) glass filler was first developed to join Al2O3 and zirconia toughened alumina (ZTA) ceramics. The microstructure, crystallization products, and interfacial reaction layer of the joint were all studied. Detailed growth process and the microstructural evolution mechanism of aluminum borate (Al18B4O33 and Al4B2O9) crystal whiskers were revealed through controlling the joining temperature and the holding time. The results showed that the Al18B4O33 and Al4B2O9 whiskers formed at the interfaces and in the joining seam, owing to the reaction between the substrates and the BAS glass system, and the precipitation out of the glass, respectively. Finally, bonded with this BAS glass filler at 1400 °C for one hour, the joints exhibited a maximum shear strength of 42 MPa at room temperature and good mechanical performance after thermal cycling.