JOINING OF SI3N4 USING AG57CU38TI5 BRAZING FILLER METAL

Hot-pressed Si3N4 was joined using Ag57Cu38Ti5 brazing filler metal at 1103 to 1253 K for 5 min in a vacuum. The interface reactions between Si3N4 and the brazing filler metal during brazing are reported. An important event is sufficient interface reaction, characterized by the formation of a layer of TiN with an appropriate thickness at the ceramic-filler interface. The joining strength of the butt joint depends on the interface reaction, and a maximum joining strength of 490 MPa measured by the four-point-bend method is achieved for the Si3N4-Si3N4 joint brazed at 1153 K for 5 min. It is also discussed how to design the best brazing filler metal for joining ceramic to ceramic or ceramic to metal. © 1990 Chapman and Hall Ltd.