Interfacial microstructure and mechanical property of brazed copper/SiO2 ceramic joint. (July 2017)

• Record Type: Journal Article
• Authors: Song, Y.Y.; Li, H.L.; Zhao, H.Y.; Liu, D.; Song, X.G.; Feng, J.C.
• Is Part Of: Vacuum. Volume 141(2017)
• Page Start: 116
• Page End: 123
• Publication Date: 2017-07
• Subjects: Copper -- SiO2 electroceramics -- Brazing -- Microstructure -- Mechanical properties; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2017.03.037
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Vacuum brazing of copper to SiO2 electroceramics was carried out using commercially obtained Ag-Cu-Ti filler alloy. The effects of brazing temperature and bonding time on the interfacial microstructure and mechanical properties were investigated. The microstructure observation revealed that the typical interfacial structure could be expressed as SiO2 ceramic/Ti5 Si3 + Ti4 O7 /Ti2 Cu + Ti3 Cu3 O/Ag (s, s) + Cu (s, s)/Copper. The migration of Ti in brazing seam, which promoted the reaction of Ti with the SiO2 ceramic, was a positive factor on the interfacial microstructure and mechanical properties. With increased the brazing temperature or holding time, the thickness of Ti5 Si3 + Ti4 O7 reaction layer thickened, meanwhile, the amount of AgCu eutectic structure decreased. The shear strength firstly increased and then decreased with brazing temperature increasing or bonding time prolonging. The maximum shear strength of 22 MPa was obtained at 850 °C for 5 min. Its fracture occurred both along the ceramic substrate adjacent to the bonding interface and along the reaction layer, showing a mixture fracture mode. Highlights: SiO2 ceramic and copper were successfully brazed with Ag-Cu-Ti filler alloy. Brazing temperature and holding time had influence on the interfacial microstructure and joint properties. Interfacial reaction mechanism of brazed joints was expounded. The optimal shear strength of joints reached 22 MPa when brazed at 850 °C for 5 min.