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

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