The role of wettability in metal–ceramic joining

The effects of oxygen, applied DC voltage and surface orientation on the wettability of ceramics by liquid metals are clarified and new methods for metal–ceramic joining are proposed based on information from wetting experiments, using three examples. The strengths of Ni–Al2O3 joints obtained at very low oxygen potentials are higher than in high oxygen potential environments. Applying a DC voltage to the interface between metals and partially stabilized zirconia is shown to improve the strength of metal–zirconia joints. Cu and SiC can be strongly joined without using active elements such as Ti and Zr by controlling the joining conditions.