Abstract:
In order to solve the problems such as the less addition and agglomeration of enhanced particles, a new composite interlayer was introduced to assist in brazing between SiC and Nb. The composite interlayer was braided by SiO
2-fiber in three dimension with loose and porous structure (3D-SiO
2-fiber). The wettability of 3D-SiO
2-fiber, microstructure and mechanical property of the joints were analyzed by SEM, XRD and electronic universal testing machine. The results show that, when the content of Ti increased from 4.5% to 6.0%, the wetting angle of AgCu-Ti active filler metal on the surface of 3D-SiO
2-fiber interlayer decreased from 90° to 3°. The wettability was significantly improved. Moreover, the immersion depth of AgCu-Ti active filler metal in 3D-SiO
2-fiber interlayer increased continuously. With the increase of brazing temperature (950 ~980 ℃) and holding time (10 ~25 min), the reaction between 3D-SiO
2-fiber and AgCu-6.0Ti active filler metal was gradually full. This method not only ensured that 3D-SiO
2-fiber was able to be added to the filler metal in a large amount, but also Cu
3Si, TiSi, α-Ti and Ti
2Cu particles dispersed in the joint. So, the residual stress was relieved and the shear strength of joint was improved. Then the reliable joint between ceramic and metal was realized.