Effect of the Cell Count on Geometrical, Mechanical, and Thermal Properties of Hierarchical‐Porous Reticulated Copper Foams from a Combination of Sponge Replication and Freeze‐Drying Techniques

Copper foams are manufactured from polyurethane template foams with a cell size of 10 and 30 ppi using two techniques: Sponge replication and a combination of sponge replication with additional freezing steps to obtain lamellar strut pores. The total porosity of foams is approximate to 93% with and approximate to 87% without additional freezing, respectively. The foams possess randomly oriented lamellar pores with a thickness of 40-56 mu m. The thickness of the material lamellae is 72-80 mu m. The specific surface area is increased by the additional lamellar pores; this value ranges from 24 to 42 cm(2) g(-1) for the 10 ppi templated foams. The influence of the cell size of the template foams and the lamellar pores within the struts on the (strut) porosity, the mechanical properties and the thermal conductivity is investigated.