Microstructure and Properties of SiC Ceramics Connected by Ni-Ti-Mo Filler

To alleviate the residual stress in SiC ceramic brazing joints and enhance their mechanical properties at room temperature, a Ni-Ti-Mo brazing filler was employed to join SiC ceramics. The results demonstrate that the SiC/Ni-Ti-Mo/SiC joint exhibits excellent bonding, with a dense and pore-free weld. The joint consists of two distinct regions: the interface reaction area and the weld center area. The microstructure of the interface reaction area is characterized by the (Ti, Mo)C phase, while the weld center area comprises Ni₂Si and Ni₃Si₂ phases, along with a significant amount of (Ti, Mo)C particles. The (Ti, Mo)C phase, which is extensively formed in the joint, has a thermal expansion coefficient similar to that of the SiC ceramic base material. This reduces the residual stress of the joint and improves its mechanical properties. The average shear strength of the joints is 176 MPa at room temperature, with fractures occurring within the base metal.