Nanoporous foam fabricated by dealloying AgAl thin film through supercritical fluid corrosion

摘要

In this research, nanoporous silver foams are fabricated through dealloying Ag35Al65 (as atomic percentage, at%) thin films in supercritical (SC) carbon dioxide. The supercritical CO2 is mixed with either HCl, water or H2C2O4 aqueous solution as the solute in the reaction chamber. Due to the low tension of the supercritical fluid, under the best operating conditions, the surface area of the as-dealloyed Ag35Al65 can reach 4.6 m(2) g(-1), and the porosity volume fraction value can reach 74%, with a smallest average pore size of around 75 nm. In an optimum supercritical CO2 environment, a lower chemical concentration can be applied and it can take less time to form a uniform nanoporous structure.