BRAZING OF SILICON-NITRIDE CERAMICS

Through a thermodynamic modelling of the reaction at ceramic/metal interface, wetting of a sintered silicon nitride containing alumina, yttria, and aluminum nitride as sintering additives was investigated with a series of Ni-based brazing alloys without addition of active elements. The alloys to wet Si3N4 were then employed for fabrication of Si3N4/Si3N4 joints. The room-temperature four-point bend strength of the joints was Found to be approximate to 120 MPa, whereas a strength of 220 MPa was achieved when the joints were tested at 900 degrees C.