Abstract: Ultralow density ionic material foams, with density approaching 0.1% of the bulk density, and synthesis methods using interconnected metallic nanowires are provided. Nanowires of various sizes and metals are dispersed into a freezable liquid through a suitable fluid exchange. Surface treatments ensure that nanowires remain sufficiently metallic and physically separated. Wire-liquid solutions can be dropped directly into liquid nitrogen in the form of droplets or placed into molds of various shapes. A freeze drying technique is employed to turn the resulting ice-wire mixture into a freestanding, low-density foam composed of interlocked nanowires. Sintering or oxidation and reduction treatment of the foam material at elevated temperatures is used to connect the nanowires into an interconnected metallic foam. Metals of the metal foams are then processed into ionic materials including oxides, nitrides, chlorides, hydrides, fluorides, iodides and carbides.

Abstract: Ultralow density pure metal foams, with density approaching 0.1% of the bulk density, and synthesis methods using interconnected metallic nanowires are provided. Nanowires of various sizes and metals are synthesized by electrodeposition into nanoporous templates such as anodized aluminum oxide or polycarbonate. The templates are etched away and the nanowires are dispersed into water through a suitable fluid exchange. Surface treatments ensure that nanowires remain sufficiently metallic and physically separated. Wire-water solutions can be dropped directly into liquid nitrogen in the form of droplets or placed into molds of various shapes. A freeze drying technique is employed to turn the resulting ice-wire mixture into a freestanding, low-density foam composed of interlocked nanowires. Finally, sintering or oxidation and reduction treatment of the foam material at elevated temperatures is used to connect the nanowires into an interconnected metallic foam, greatly improving the strength of the structure.