Experimental study on drop penetration and wetting characteristics of sintered copper powders with nanostructures

In this study, nanostructures were fabricated on sintered copper powders through alloying-dealloying method for investigating and analyzing drop penetration and wetting characteristics. Based on the high-speed video imaging, the kinetics of droplets immersing process were studied for multi-scale composite compact (MCC), featured with the microns for copper particle sizes and nanometers for the surface structures. The comparisons of various sizes of copper powders and different initial falling heights were conducted to explore the effect of porous structures. The results indicated that the nanostructures, with pore size and ligament size of approximately 30 nm and 50 nm respectively, could effectively enhance the hydrophilic performance for the sintered copper compacts. Moreover, larger powder size could lead to faster penetration, while the higher initial falling height facilitated the increase of the maximum spreading diameter of droplet, resulting in lower penetration time.