Preparation of Ni-based pasty filler and its application in C/C composites brazing

A spherical Ni-based filler metal powder with fine particle size and a uniform distribution was prepared by vacuum melting inert gas atomization method. At the same time, an organic binder carrier suitable for pasty filler metal was prepared. A Ni-based pasty filler was prepared by mixing the filler metal powder with a binder and stirring at a high speed. The C/C composites were jointed using the prepared pasty filler. Subsequently, the strength of the joint was tested, and the interface characteristics of the brazed joint were analyzed by scanning electron microscope, EDS spectrum analyzer, x-ray diffractometer and metallographic microscope. The results show that pasty filler can increase the contact area before brazing, which is beneficial to increase the metallurgical bonding strength of the joint. Under suitable brazing conditions, a gradient buffer structure can be constructed to reduce thermal mismatch and increase joint strength. (paper)