Improved interfacial mechanical properties of the Ag film metallized AlN substrate through an in-situ formed g-C3N4 nano-interlayer

In this work, a nanocrystalline/amorphous graphitic carbon nitride (g-C 3 N 4 ) nano-interlayer was formed in-situ between AlN substrate and Ag film through ultrasonic spraying combined with subsequent heat treatments . The interface mechanical behavior and failure mechanism of the novel AlN/Ag structures with different thicknesses of g-C 3 N 4 nano-layers were investigated using experimental and numerical simulation methods. Following four-point bending test, the debonded surfaces of Ag film and AlN were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrated that the in-situ-formed g-C 3 N 4 nano-interlayer significantly improved the mechanical properties of the AlN/Ag interface due to the mechanical interlocking effect combined with the strong interfacial bonding strength . The g-C 3 N 4 nano-interlayer effectively relieved stress concentration near the Ag film and delayed the interfacial damage in the AlN/Ag structure, leading to significant improvement in interfacial fracture toughness . The thickness of g-C 3 N 4 nano-layers played a critical role in determining the mechanical performance of the AlN/Ag structure. Specifically, the structure with 90 nm thick g-C 3 N 4 interlayer exhibited the highest critical fracture energy G IC and maximum interfacial peeling stress σ max , with increases of 442 % and 132 %, respectively, compared with that without g-C 3 N 4 .