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°C to 950°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.