Preparation and performances of nanoporous copper for low temperature bonding

Nanoporous metals fabricated by dealloying have been utilized in a wide variety of applications including catalysis, sensors and actuators as well as low temperature bonding. In this work, nanoporous copper (NPC) for low temperature bonding was prepared by selectively dissolving Zn atoms from the Cu-Zn alloy, and the influences of electroplating time of Zn and dealloying duration on the characteristics (surface morphologies, pore or ligament size) of nanostructures were investigated. After electroplating Zn for 2 minutes to 15 minutes, nano-sized porous structures can be formed in all samples and with increasing electrodeposition time of Zn, the pore sizes of NPC decreased from 52nm down to 26nm. Moreover, slight coarsening occurred to the ligaments as the etching time extended. All the surface morphologies and microstructures of the samples were examined by means of optical microscope and scanning electron microscopy (SEM). The suitable electrodeposition time was suggested for 12 minutes and the appropriate dealloying duration was 10 minutes.