Joining Si3N4 to type 405 steel with soft metal interlayers

Abstract

The suitability of four pure metals, Ni, Fe, Ti, and Nb, as interlayers for bonding silicon nitride to type 405 ferritic stainless steel has been examined. Bonding was carried out by hot isostatic pressing at temperatures between 1473 and 1673 K under a pressure of 100 MPa. Of the metals tested, Fe and Nb formed the strongest interfacial bonds with Si₃N₄. To reduce the influence of residual stress in joints, Fe/W and Nb/W laminated interlayers were also examined. The use of W restricted the contraction of Fe or Nb, and the Si₃N₄/steel joints with these interlayers had a tensile strength of more than 50 MN m^?2. A low-pressure (10 MPa) bonding process was also used for the Fe/W interlayer.

MST/470