Joining Of The Sicf/Sibcn Composite With Conipdnbcr Filler Alloy And The Control Of The Interfacial Reactions

The joining of the SiCf/SiBCN composite was difficult due to the undue reactions between the SiCf/SiBCN composite and the common Ni- or Co-based filler alloy. In this paper, a new filler alloy with the nominal composition of Co-20Ni-12Pd-18Nb-15Cr (wt.%) was newly designed to join the SiCf/SiBCN composite. Compared with the BNi-5 filler alloy, the periodic banded structure in the reaction layer was eliminated. During the brazing process, the element Cr played an active role in the interfacial reactions and formed Cr23C6 layer at the surface of the SiCf/SiBCN composite. The interfacial reaction layer could inhabit the diffusion of the elements Co and Ni to the SiCf/SiBCN substrate. And then the interfacial reactions were controlled well. Under the brazing condition of 1200 degrees C/10 min, the average joint strength was increased from 18.2 to 54.9 MPa.