Metal foam with self-formed skin fabricated by electroforming method

• A novel vacuum-induced electroforming technique is proposed, the vacuum negative pressure drives electrolyte flow through narrow and tortuous micro-channels to achieve electroforming thickening on the struts of open-cell metal foam. • The vacuum-induced electroforming technique was employed to generate a skin on one side of the open-cell metal foam. This skin layer grows synchronously with the strut electroforming, ultimately yielding an integrated foam-skin structure. • Both simulation and experimental results demonstrate that the electroformed layer’s inhomogeneity increases with electroforming time, while reducing current density proves more effective than adjusting anode-to-cathode distance for improving thickness uniformity. • Mechanical testing reveals that skin layers exceeding 34.6 μm in thickness substantially enhance the foam’s mechanical properties, attributable to the establishment of sufficient interfacial bonding sites between the foam struts and skin layer. A metal foam with the interface-free connection to its skin offers excellent heat transfer, superior mechanical strength and high microstructural stability. This study presents an innovative vacuum-induced electroforming system and a corresponding methodology for fabricating conformal skins on metal foam. The investigation combines COMSOL simulation, experimental characterization, and mechanical property evaluation to elucidate the evolution of electroforming layer distribution and its impact on structural performance. The results demonstrate that extended electroforming duration leads to progressively greater thickness nonuniformity, while reducing current density proves more effective than adjusting anode-to-cathode distance for improving deposition uniformity. Mechanical testing reveals that skin layers exceeding 34.6 ± 2.4 μm in thickness substantially enhance the foam’s mechanical properties, attributable to the establishment of sufficient interfacial bonding sites between the foam struts and skin.