**3.5 Analysis of Al2O3-SnTi2 joint**

**Figure 22** shows the interface of SnTi2-Al2O3 joint. From the map of planar distribution of elements, it is obvious that the active Ti element significantly contributes in bond formation. It forms a continuous reaction layer, similarly as in the case of SnAg3.5Ti4(Ce,Ga) solder. This reaction layer is formed by Ti reaction with oxygen from ceramics at formation of titanium oxides, which alter the surface tension of ceramics and thus allow its wetting by solder. The effect of other elements (except Ti) upon bond formation was not observed (**Figure 23**).
