Characteristics of precursor film in the wetting of Zr-based alloys on ZrC substrate at 1253 K

• Wetting with precursor film is one of the typical characteristic of adsorption wetting.
• Formation of precursor film needs relative inertia at liquid–solid interface.
• Formation of precursor film needs strong affinity at liquid–solid interface.

The study of precursor film is crucial to understanding the mechanism of triple line moving for the wetting at high temperatures, however, it remains incomplete. In this work, the wetting of ZrC by Zr-based alloys (Zr50Cu50, Zr50Cu40Al10 and Zr55Cu30Al10Ni5) was studied by a modified sessile drop method at 1253 K. A transition of the precursor film was developed by the addition of constituent elements in the system. Based on the results of a series of wetting systems, the formation condition of the precursor film was proposed, i.e., the occurrence of the precursor film needs to satisfy that active composition has a strong affinity with substrate, and can remain relatively inert. The spreading dynamics were analyzed, which indicated that the wetting with a precursor film was a typical characteristic of adsorption wetting.