Synthesis of open-cell copper foam using friction sintering

Abstract

A technique for doing solid-state sintering on friction stir welding or milling machines is developed. Heat and pressure needed for sintering are generated using a rotating tool with a flat shoulder. The developed process results in fast heating and cooling rates, sharply reducing sintering time. Sintered parts can be extracted within minutes from end of sintering. The process is cost-effective and can be used to produce large, three-dimensional sintered parts. The technique is used to fabricate open-cell copper foam using sintering and dissolution process with NaCl particles as space holders. Microstructural features of fabricated foam are studied using scanning electron microscopy, microcomputed tomography, and optical microscopy. Its mechanical properties are studied using compression tests. Plateau stress, compressive strength, energy absorption density, and thermal conductivity of obtained foam are on par with those reported in literature for foams obtained using furnace sintering and friction compaction methods. The developed foam has three-scale microstructure and could be used in heat exchanger, sound absorption, catalysis, boiling, and filtration applications.