Joining of Cf/SiBCN composite with two Ni-based brazing fillers and interfacial reactions

C-f/SiBCN ceramic composite was joined using Ni-19Cr-10Si (BNi5) and Ni-33Cr-24Pd-3.5Si-0.5B filler alloys at 1170 degrees C for 10 min. Two kinds of Ni-based filler alloys exhibited good wettability on the C-f/SiBCN composite, with a contact angle of 13 degrees and 4 degrees, respectively. The microstructures of the brazed joints were investigated by electron-probe microanalysis (EPMA), and three-point bend test was conducted for the joints at room temperature. When being brazed with BNi5 filler alloy, no evident reaction layer was observed at the surface of the joined composite, and the joint microstructure was characterized by Ni2Si matrix with scatteringly distributing mixture compounds of Cr23C6, Ni2Si and CrB. While Ni-Cr-Pd(Si,B) brazing alloy was used, a Cr23C6 reaction layer with a thickness of 11 mu m was formed at the surface of the base composite. In the central part of the brazed joint, the phases were composed of Ni(Cr,Si) solid solution and complex compounds including Pd2Si, (Ni,Pd)(2)Si and Ni-B. The strength of C-f/SiBCN joint brazed with BNi5 filler alloy was 62.9 MPa at room temperature, whereas that with Ni-Cr-Pd(Si,B) filler alloy was at the same level. Copyright (C) 2017, The editorial office of Journal of Materials Science & Technology. Published by Elsevier Limited.