Brazing of silicon carbide ceramics with Ni-Si-Ti powder mixtures

In many industrial applications, large-sized SiC components are increasingly desired through a conventional and pressureless brazing method. In present study, Ni-Si-Ti powder mixtures containing 0 similar to 10 wt.% Ti were used to braze SiC ceramics. Differential thermal analysis (DTA) and wetting tests were carried out to determine the appropriate joining temperature to be at 1450 degrees C. Microstructure, phase constituents, and mechanical strength of the prepared SiC joints were characterized. For a brazing composition without Ti addition, the interlayer primarily consists of NiSi and Ni3Si2 phases. With the addition of Ti, Ni49Ti14Si37 phase is newly formed within the interlayer besides the Ni-Si compounds. The bending strengths of SiC joints locate in 66 similar to 75 MPa as brazed at present conditions and the specimens generally fracture from the interface between alloy interlayer and SiC substrate.