Reactive brazing Cf/SiC to itself and to Mo using the NiPdPtAu-Cr filler alloy

The NiPdPtAu-Cr filler alloy was proposed for joining C-f/SiC composites. The wettability on C-f/SiC composite was studied by the sessile drop method at 1200 degrees C for 30 min. Under the brazing condition of 1200 degrees C for 10 min, the C-f/SiC-C-f/SiC joint strength was only 51.7 MPa at room temperature. However, when used a Mo layer, the C-f/SiC-Mo-C-f/SiC joint strength was remarkably increased to 133.2 MPa at room temperature and 149.5 MPa at 900 degrees C, respectively. At the interface between C-f/SiC and Mo, Mo participated in interfacial reactions, with the formation of Cr3C2/Mo2C reaction layers at the C-f/SiC surface. The improvement in the joint strength should be mainly attributed to the formation of MoNiSi. The C-f/SiC-Mo joint strength was 86.9 MPa at room temperature and 73.7 MPa at 900 degrees C, respectively. After 10 cycles of thermal shock test at 900 degrees C the C-f/SiC-Mo joint strength of 71.6 MPa was still maintained. (C) 2017 Elsevier Ltd. All rights reserved.