SOLID-STATE BONDING OF SILICON-NITRIDE CERAMICS WITH NICKEL CHROMIUM-ALLOY INTERLAYERS

Si3N4 ceramics with Al2O3 and Y2O3 as additives were joined with an 80 wt% Ni‐20 wt% Cr alloy sheet as an insert layer. Joining was performed by hot‐pressing between 1000° and 1350°C in argon, and under uniaxial pressures in the range of 50 to 100 MPa. The average joint strength, evaluated by four‐point bending, was large enough (>300 MPa) for some industrial applications. However, the scatter in strength was relatively large, because of the formation of interfacial pores, which were not distributed uniformly at the bond interface. The effects of joining pressure and N2 gas partial pressure on the formation of the pores were confirmed microscopically. Cr coating on the Si3N4 ceramic before joining contributed to reduce the joint strength scatter. The major interfacial reaction products were Cr nitrides. Copyright © 1990, Wiley Blackwell. All rights reserved