Microstructural and mechanical characterization of the Si3N4/Si3N4 joint brazed using Au–Ni–V filler alloys

In this study, two Au–Ni–V filler metals were used to braze Si3N4 ceramic in the form of foils. The effects of brazing temperature and V content in the filler alloy on microstructure and bonding strength of the joint were studied. The results reveal that a VN reaction layer with a thickness about 4 μm was formed at the interface between Si3N4 substrate and filler alloy. With increasing brazing temperature or V content the thickness of VN reaction layer increased. A maximum joint bending strength of 242 MPa was achieved when the joint was brazed at the temperature of 1423 K for 30 min using Au58.7Ni36.5V4.8 filler alloy. The bonding mechanism was discussed with reference to the discovered phases and brazing parameters.