Bonding mechanisms and shear properties of alumina ceramic/stainless steel brazed joint

Al ₂O ₃ ceramic/stainless steel joints were fabricated by activated molybdenum-manganese (Mo-Mn) sintering metallization plus vacuum brazing using Ag-28 wt.% Cu alloy. The bonding mechanisms including metallization and interfacial bonding were analyzed and discussed by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD). Tests were also carried out to examine the influence of brazing on joint shear strength. The metallization mechanisms of glassy phase migration and chemical reaction were confirmed experimentally, while Ni coating was found to play a key role in the joining of metallized ceramic to metal via the Ag-Cu filler layer. As a result of the joining, the average shear strength of the joints exceeds 95 MPa, with the maximum reaching 110 MPa.