Vacuum brazing of Al₂O₃ ceramic using Au-based brazing filler

First, surface metallization of Al₂O₃ ceramic was carried out at 880℃ heat treatment for 10 min using AgCuTi as active brazing filler, and then, vacuum brazing of the ceramic was performed at 980℃ for 10 min using two Au-based brazing fillers. The results showed that a thin diffusion layer containing TiO₂ and Al₂O₃ was formed at the Al₂O₃/Au-Ni/Al₂O₃ joint interface close to Al₂O₃ side. In Al₂O₃/Au-Cu/Al₂O₃ joint, besides Ti-O compound, Ti-Au compound existed in the diffusion layer. The test results at room temperature showed that the shear strength of two ceramic joints were 95.5 MPa and 102.3 MPa, respectively.