Fabrication of copper foams by powder metallurgy

ABSTRACT A method for the fabrication of copper foams by powder metallurgy, employing carbamide beads as space holders, is presented. These are removed by water dissolution before sintering the compact. The method allows for a precise control of the cell characteristics (size, shape and distribution) within an interconnected porosity. The use of metal powder promotes the formation of an inherent porosity in the cell walls that affects their mechanical properties, producing failure at a lower than expected tension. Optimization of the method was achieved by selecting the sintering parameters (compaction pressure, temperature and atmosphere). The mesostructure and microstructure of the samples were characterized by traditional microscopy (scanning electron microscope SEM) and x-ray tomography. The latter technique allows a 3D visualization of the cell distribution, a complete characterization of the mesostructure, the evaluation of the porosity and to follow the cell evolution during compression tests.