Formation and Characterization of Monolithic Nanoporous Copper by Chemical Dealloying of Al-Cu Alloys

Monolithic nanoporous copper (NPC) ribbons can be fabricated through chemical dealloying of melt-spun Al-Cu alloys with 33-50 at % Cu under free corrosion conditions. The microstructure of these NPC ribbons was characterized using X-ray, diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and transmission electron microscopy. The experimental results show that the melt-spun Al-Cu alloys with 33-50 at % Cu. are composed of one or a combination of Al2Cu and AlCu intermetallic compounds. Both Al2Cu and AlCu can be fully dealloyed, and the synergetic dealloying of Al2Cu and AlCu in the two-phase Al-Cu alloys results in the formation of NPC with a homogeneous porous structure. The NPC ribbons exhibit an open, bicontinuous interpenetrating ligament-channel structure. NPC is a promising high strength/low density material due to its high porosity and yield strength of 86 +/- 10 MPa. In addition, bulk NPC rods and slices can also be synthesized using the same strategy. These NPC ribbons, rods, and slices can serve as model materials to investigate the mechanical, physical (for example, electrical resistivity), and chemical properties associated with random porous structure of nanoporous solids.