Joining of alumina using a V-Active filler metal

Alumina joints can be produced by brazing with the commercial Au-Ni-V-Mo filler metal, Nioro ABA. Optimum brazing conditions and surface preparation of the workpieces lead to Al sub 2 O sub 3 /Al sub 2 O sub 3 joints with strength distributions similar to that of the monolithic ceramic. Of more significance is the fact that these joints retain measurable strengths up to 900 deg C and after 100 h oxidation. A reaction layer between the ceramic and braze alloy could not be found with the analytical techniques employed. The filler metal was used also to join Al sub 2 O sub 3 to Fe-42% Ni alloy. Iron and Ni dissolve in the filler metal extensively, with no apparent effect on the brazing process. Despite the relatively small thermal expansion mismatch between Al sub 2 O sub 3 and Fe-42% Ni, residual stresses play a role in the quality of these joints.