Reactive wetting and interfacial characterization of ZrO2 by SnAgCu-Ti alloy

The reactive wetting behavior of zirconia with SnAgCu-x%Ti (SAC-x%Ti, wt%, x?=?1, 4) alloy was investigated via the sessile drop method in isothermal experiments. As temperatures elevated, the final contact angle decreased and the minimum contact angle of 21° and 7° were obtained at 1000?°C for SAC-1%Ti and SAC-4%Ti droplets, respectively. Kinetic calculations indicated that the spreading of SAC-Ti droplets on zirconia was controlled by interfacial reaction and the wetting activation energy was 108.8?kJ/mol. The reaction products distribution and morphology in droplets were influenced vastly by the addition of Ti. Along with the increase of Ti content from 1% to 4%, a great deal of Ti-Sn intermetallic compounds (IMCs) were generated in droplets, thereby the outline of droplets were transformed from hemispherical into similar trapezoidal due to the limited spreading and fluidity of droplets. Owing to the interfacial reaction between active elements Ti and zirconia and the subsequent formation of the Ti-O layer, the wettability of SAC-Ti/zirconia was greatly promoted. According to transmission electron microscopy (TEM) analysis, the thin Ti-O reaction layer consisted of the Ti₂O, Ti₄O₇, Ti₇O₁₃ and TiO₂ phase.