Wettability and joining of SiC by Sn-Ti: Microstructure and mechanical properties

Wei Fu¹，Xiaoguo Song^1,2，Ruichen Tian²，Yuzhen Lei²，Weimin Long³，Sujuan Zhong³，Jicai Feng^1,2

1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology2. Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai3. State Key Laboratory of Advanced Brazing Filler Metals and Technology, Zhengzhou Research Institute of Mechanical Engineering

摘 要：Reliable Si C/Sn-Ti/Si C joints were obtained by brazing（950?C/10 min） and soldering（250?C/2 min） following premetallization depend on the wettability of Sn-Ti on Si C. The microstructures of Sn-Ti/Si C interface were characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscopy, and the mechanical properties of joints were evaluated by shear tests. Active Ti enhanced the wettability of Sn on Si C with the decrease of contact angle from 150?to 20?. Ti direct reacted with Si C to produce Ti C and combines with released Si forming Ti₅Si₃. Much lower Ti concentration per contacting area in brazing and metallization, compared to wetting, resulted in defective bonding of Sn-Ti/Si C and few amounts of interfacial products（thin Ti C layer or partial covered Ti C layer with Ti₅Si₃）. All of the Si C/Si C joints possess a similar shear strength of 27–32 MPa and rupture through ?-Sn matrix in ductile fracture.

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