Interfacial microstructure and properties of Si_3N_4 joints brazed using TiNi-V eutectic brazing alloy

TiNi-V eutectic brazing alloy was fabricated by vacuum arc melting, and its spreadability on the surface of Si₃N₄ ceramic was investigated.The brazing of Si₃N₄ ceramic was achieved using TiNi-V brazing alloy.The typical interfacial microstructure was Si₃N₄/TiN+Ti-Si compounds/NiV.The effect of brazing temperature on the interfacial microstructure and properties of joints was investigated.The results showed that with the increasing of brazing temperature, the reaction between molten brazing alloy and Si₃N₄ ceramic intensified and the thickness of TiN+Ti-Si compounds layer increased gradually.Moreover, lots of microcracks were formed in the joints due to the residual stress in joints, which deteriorated the joining properties.The highest shear strength of 28 MPa was obtained when the specimen was brazed at 1 200℃ for 10 min.The joint fractured in TiN+Ti-Si compounds layer, which belonged to brittle fracture.