Insight into the wetting behavior of AgCu-xTi on ZrO2: Spreading and microstructural evolution

Understanding the wetting behavior is significant to the fabrication of ceramic/ceramic (or metal) components. Here, the typical AgCu-xTi/ZrO2 system is selected and its wetting behavior is studied by improved sessile drop method for various Ti content (x = 1, 2, 3, 4, wt%) at temperature range of 800 degrees C to 950 degrees C. The spreading of AgCu-xTi melt on ZrO2 substrate consists of two stages: (I) rapid-spreading stage and (II) sluggish-spreading stage. The spreading is determined by the interfacial interactions. Two kinds of products, TiO and Cu3Ti3O, nucleate and grow at the interface. Because of their metallic property, the wettability of AgCu-xTi/ZrO2 is significantly improved. Before continuous layer forms, the transportation of reactive mass is fast. Therefore, plenty of interfacial products precipitate at the interface resulting in the rapid spreading of AgCu-xTi melt on ZrO2. After that, the formed continuous acts as barrier suppressing interfacial reactions, thereby a sluggish-spreading stage is followed. This work provides insights into the interfacial microstructure inducing spreading of the AgCu-xTi/ZrO2 system.