Homogeneously bimodal nanoporous copper by laser processing-dealloying approach

Bimodal nanoporous structure shows great potential in a wide variety of applications. So far, however, a scalable fabrication method for bimodal nanoporous structure with controllable morphology and size remains a critical challenge. Herein, we prepare a homogeneously bimodal nanoporous copper which consists of nanoslit and nanopore through combined laser processing and dealloying. The nanoslit and nanopore size can be easily altered by simply controlling the laser processing parameters. With decreased heat input during laser processing, the width of nanoslit decreases from 200 nm to 100 nm and the average size of nanopore decreases from 23.7 to 14.0 nm. The bimodal nanoporous copper is found to be principally influenced by metallurgical reaction during laser-material interaction. Compared with equilibrium-solidified as-cast alloy, phase separation and refined microstructure induced by non-equilibrium solidification through laser processing facilitates corrosion rate during dealloying and induces bimodal nanoporous structure after dealloying.