Synergistic regulation of molten metals/ceramic wetting by high magnetic fields and active element addition

Conventional methods for controlling the wettability between molten metals and ceramics often modify the intrinsic reaction characteristics of the system or result in inadequate joint quality and service reliability. To address this, we propose a coupled strategy that combines a high magnetic field with a minor addition of an active element to regulate wetting. The wetting of molten Al- x wt.%Cu ( x = 0, 1, 2) on R-plane α-Al 2 O 3 substrates was systematically investigated under high magnetic fields. By integrating interfacial microstructural characterization with theoretical analysis, the mechanism of wetting control was clarified. After applying a 6 T magnetic field and adding 2 wt.%Cu, the wettability of the Al/α-Al 2 O 3 system was significantly improved, with the contact angle decreasing from 127.6° to 74.1° (-41.2%) and the spreading diameter increasing from 2.2 mm to 4.3 mm (+95.9%). Microstructural observations confirmed that no interfacial reaction occurred after wetting. The fundamental cause of the enhancement is the field-induced formation of ordered Al atomic layers epitaxially aligned with the substrate and coherently matched intermetallic phases at the interface. This interfacial ordering substantially lowers the solid–liquid interfacial energy, thereby significantly improving wettability. The proposed wetting-control method offers a viable route to further improve the fabrication quality of metal/ceramic composites.