High temperature brazing of Si₃N₄ ceramic using Cu-Ti active filler metal

Self-joining of Si₃N₄ using Cu80Ti20 active filler metal was demonstrated under different process parameters. Joints with no defects and cracks were obtained as the holding time is about 5-15 min and brazing temperature is about 1 413-1 493 K. The results shown that the microstructure of the joint can be described as Si₃N₄ ceramic/TiN layer/Cu-Ti solid solution+Ti₅Si₃/TiN layer/Si₃N₄ ceramic. On the condition of 1 413 K/10 min,Element Ti of solid solution diffused to the interface and reacted with ceramic,then compact and continuous reaction layer of thickness about 1 μm formed. The effects of brazing temperature and holding time on the width of the brazing seam,interface layer and the strength of joint were investigated, respectively. On the prescribed experiment condition shear strength of joint was up to 105 MPa.