Low temperature brazing nickel with Ag nanoparticle and Cu-Ag core-shell nanowire nanopastes

Ag nanopastes and Cu-Ag core-shell nanowire nanopastes were used for brazing Ni 200. The influences of the brazing temperature and brazing pressure on the mechanical properties and microstructure of joints were investigated. The results show that the shear strength of joint was significantly improved from 12 MPa to 46 MPa with increasing the brazing temperature from 300 °C to 850 °C and brazing pressure from 7 MPa to 26 MPa. It is indicated that both a high brazing pressure and brazing temperature are beneficial for the diffusions between adjacent nanoparticles and nanowires, the seam and based materials and thereby improve the shear bonding strength. Successful joints of 40.6 MPa bonding strength were achieved with 700 °C brazing temperature, which indicated that silver nanopaste can be used for brazing Ni at a lower brazing temperature than that of commercial BAg-8 brazing filler metals.