Brazing Si3N4 ceramic to AISI 5140 steel under pressure

Pressures (0 to 40 MPa) were applied to the joints of Si3N4 ceramic to 5140 steel during vacuum brazing with Ag-Cu-Ti active filler metal. Pressurization started at various temperatures (873,973, and 1073 K) and ended at room temperature during cooling. Results show that there is an optimum starting temperature to pressurize, at which the maximum room temperature shear strength of the joint is obtained.