Joining particulate and whisker ceramic composites by plastic flow

Joining of bulk ceramics by plastic flow has been demonstrated for several fine-grained ceramics. We have joined, for example, submicrometer 3 mol% Y2O3 partially stabilized ZrO2 (YSZ) and YSZ-toughened Al2O3. The interlayers in these cases consisted of dense, submicrometer-grain-sized pieces of ceramics that have been shown to exhibit superplastic flow. We have extended the joining work to include incorporation of 15 vol.% SiC or 20 vol.% TiC whiskers within the bond layer. Unlike YSZ/Al2O3, because of the presence of the whiskers, YSZ/Al2O3/SiC and YSZ/Al2O3/TiC do not deform superplastically. However, virtually perfect YSZ/Al2O3 joints with and without whiskers could be made by compressing at 1300–1350 °C and stresses of <20 MPa.