Abstract: The buffer layer material itself may be influential to the bond strength between active brazing filler and ceramics.For Ag_(57)Cu_(38)Ti_5 filler metal,Cu or Ta is excellent buffer layer material, but Kovar or Ni-15Cr-15Co is worse.It was important to design a layer of soft buffer,such as Cu,to relax interfacial stress rather than hard buffer layer,such as Mo,to avoid stress. There is an optimum thickness range of soft buffer layer,saying h/L=0.02—0.1. It was a good solution to the interfacial stress problem to use soft/hard buffer layer to increase metal/ceramics joint strength.Finally,an idea of designing gradual materials as buffer layer between metal and ceramics was suggested.

Key words: ceramic/metaljointing, Sialon, steel 40Cr, active brazing, interlayer