Influence of Brazing Process on Microstructure and Properties of SiC/Kovar Vacuum Brazed Joint

SiC ceramic was brazed to Kovar alloy with Ag-Cu-Ti/Cu/Ag-Cu soft compound interlayer solder.The influence of the brazing temperature(810-900℃)and holding time(5-30 min)on the microstructure and me-chanical properties of the joins were studied. The results demonstrated that with the increase of the brazing tempera-ture,the thickness of the ceramic interface reaction layer would increase. The increase of the brittle compounds inthe joint was not conducive to the release of residual stress. The shear strength of the brazed joints was reduced.With the increase of the holding time,the shear strength of brazed joints first increased and then decreased. Whenthe brazing temperature was 810 ℃ and the holding time was 15 min,the maximum shear strength of the brazedjoint was 33 MPa. The typical microstructure of SiC/Kovar joint was:SiC ceramic/Ti C/Cu(s,s)+Ag(s,s)/Fe₂Ti+Fe₃Si/Kovar alloy.