Reactive air wetting and brazing of Al ₂O ₃ ceramics using Ag–Nb ₂O ₅filler: Performance and interfacial behavior

Abstract

We firstly performed the reactive air wetting and brazing of Al 2 O 3 ceramics using Ag-(0.5-12)Nb 2 O 5 fillers, where Nb 2 O 5 can react with liquid Ag and O 2 from air to generate AgNbO 3 . The contact angle of the Ag-Nb 2 O 5 /Al 2 O 3 system almost linearly decreases from ~71.6° to 32.5° with the Nb 2 O 5 content increasing, and the joint shear strength reaches the maximum of ~65.1 MPa while employing the Ag-4Nb 2 O 5 filler, which are mainly related to the formation and distribution of the AgNbO 3 phase at the interface. Moreover, the interfacial bonding and electronic properties of related interfaces were investigated by first-principles calculations. The calculated works of adhesion (W a ) of Ag( 111)/Ag-O-AgNbO 3 (001) and AgNbO 3 (001)/Al 2 O 3 (100) interfaces are higher than that of the Ag(111)/Al 2 O 3 (110) interface, indicating good reliability of the Ag/AgNbO 3 /Al 2 O 3 structure. The relatively large interfacial charge transfer indicates the formation of Ag-Ag, Al-O, and Ag-O bonds in the Ag/AgNbO 3 /Al 2 O 3 structure, which can contribute to the interfacial bonding.