Interfacial microstructure of partial transient liquid phase bonding of Si3N4 to nickel-base superalloy using Ti/Au/Ni interlayers

The Si3N4 ceramic was joined to DZ483 superalloy by partial transient liquid phase bonding using Ti/Au/Ni/Ti multi-interlayers. The interfacial microstructure and crystallographic orientations between the Si3N4 ceramic and the Ni interlayer were analyzed by scanning and transmission electron microscope. The results indicated that the interfacial microstructure of the joint consists of three main phases: a TiN reaction phase, an Au-rich phase, and a lamellar Ni-rich phase distributed homogenously in the Au-rich phase. The nano-scale wavy interface was observed at the Si3N4/TiN interface, which was thought to provide high mechanical strength. A possible mechanism for the formation of interfacial structure observed was discussed.