Theoretical Investigations on Interfacial Behavior of Ag–Cu–Ti/Si3N4 Wetting System

The wetting interface of Ag–Cu–Ti alloy on Si3N4 ceramic was researched by the sessile drop method, and a uniform TiN–Ti5Si3 mixed layer of ˜ μm was formed at the interface. The work of adhesion (Wa), interfacial energy and electronic properties of Ag(111)/Si3N4(0001), Ag(111)/TiN(111) and Ag(111)/Ti5Si3(0001) interfaces were studied by DFT calculations to investigated the mechanisms lying behind the excellent bonding strength of Ag–Cu–Ti/Si3N4 wetting system. The computational outcome shows that the Ag(111)/N-terminated TiN(111) interface presents the maximum Wa, and the interfacial energy of the Ag(111)/Si3N4(0001) interface is higher than those of the Ag(111)/TiN(111) and Ag(111)/Ti5Si3(0001) interfaces, indicating that the TiN–Ti5Si3 mixed layer formed at the interface does play a positively role in enhancing the interfacial strength of Ag–Cu–Ti alloy on Si3N4 ceramics. And the electronic properties reveal that an existence of charge transfer between Ag and N atoms leads to the ionic bond formation at the Ag/AlN interface.