Joining of SiC using CoFeCrNiCuTi high entropy alloy filler by electric current field assisted sintering

Abstract

SiC ceramics were brazed by electric field-assisted sintering technology using CoFeCrNiCuTi high-entropy alloy as joining filler. The effect on the interface microstructure and bend strength of brazed joints at different brazing temperature was systemically studied. The interfacial reaction was controlled by adjusting the brazing temperature. The main components in the brazing seam are high-entropy alloys FCC (HEAF), C, TiC, CrC, and Cr23C6 phase. Furthermore, the maximum bending strength of 54 MPa was found when brazed at a lower temperature of 1125℃. In addition, due to the electric field-assisted sintering technology and the high-entropy effect of the CoFeCrNiCuTi filler, the diffusion of elements and the formation of solid solution were accelerated. This suggests that the current field was beneficial to improve the inter-diffusion between the CoFeCrNiCuTi filler and SiC ceramics. Consequently, the low-temperature rapid brazing of SiC ceramics was realized, and this technology provides a new filler system for ceramic brazing.