Nanoporous Copper Micro-structure And Density Control

Porous metal materials consist of a certain scale metal particle or fiber and microporosity which can be utilized as new functional materials. Nanoporous metals have attracted considerable attention for a wide range of applications due to their low density. In inertial confinement fusion (ICF) target research, porous metal materials as a target material or target parts, mainly used in the double-shell target. They are also particularly attractive to serve as base materials in research fields such as catalysis, filtration, sensors and biotechnology.Dealloying occurs when an alloy is immersed in an electrolyte under a driving force such that the more reactive component dissolves, and the more noble component remains stable in metallic form. With different traditional metallic foams, nanoporous metals prepared by this method have a uniform structure, high purity, continuously adjustable pore size from several nanometers to several microns, tunable materials shape and size (film or bulk material) and so on.In this paper, a comprehensive introduction of nanoporous copper, various growth techniques, and the research background had been reviewed. Nanoporous copper with the different morphology can be synthesized by free corrosion dealloying in dilute HCl solution with Zn-Cu film and Mn-Cu alloys. The X-ray Diffraction (XRD), the Scanning Electron Microscopy (SEM), the Energy Disperse Spectroscopy (EDS) and the X-ray Photoelectron Spectrometry (XPS) were employed to characterize the crystalline and microstructure.The effects of dealloying parameters, such as initials alloy composition, acid concentration, dealloying time and dealloying temperature have been studied on microstructure and density of nanoporous copper. The results indicate the best threshold of alloy composition is 32at. %～23at.%. However, the homogeneity and stability of the nanoporosity strongly depends on acid concentration. Larger pore size with the dealloying time increased and coarsening of ligaments occurs in nanoporous copper. With optimal etching conditions, the dealloying time can be shorten by controlling the dealloying temperature. In addition, the influence of dealloying parameters on the density of nanoporous copper is also investigated. In order to obtain low-density nanoporous copper, the key points are reduction of residual Mn content and restraint of volume shrinkage.