Among other applications, open cell foams are used as catalyst supports and (active) filters due to a high thermal conductivity and high fluid permeability in combination with a low relative density. The most important manufacturing process for open cell foams is the sponge replication technique established by Schwartzwalder and Somers; this technique is widely applied in the fabricating of ceramic foams and it allows to obtain high porosity foams. However, for the manufacturing of open cell metal foams investment casting, casting around hollow spheres, metal injection molding and space holder methods are currently applied instead of the sponge replication technique.
In this study the manufacturing of open cell aluminum foams by the sponge replication technique using 20 ppi polyurethane foam templates and an aqueous aluminum slurry is presented. The influence of the template burnout temperature and the sintering conditions (temperature and atmosphere) on the strut microstructure, porosity, compressive strength and thermal conductivity of the obtained foams are investigated and the most relevant process-structure relations are discussed.