Open-porous copper foams with additional strut porosity are manufactured by two
different manufacturing routes. The first is based on the Schwarzwalder sponge
replication technique. The second method is a combination of Schwartzwalder
sponge replication and freezing technique in which an additional strut porosity is
generated inside the struts of the sponge-replicated foams by freezing at 20 C for
24 h and subsequent sublimation. Thermal processing of both types of foams is
conducted at 500 and 900 C for 6 h in a hydrogen-containing atmosphere to
reduce copper oxides and to facilitate the sintering process of the copper powder
particles. Despite significant shrinkage of both foam series after thermal processing,
hollow struts and lamellar pores keep their shape and do not collapse. The
influences of the additional lamellar pores and thermal processing temperature on
the cellular structure, porosity, specific surface area, yield strength, absorbed
energy, and thermal conductivity are studied. The additional strut porosity generated
by the freezing step significantly increases the specific surface area of the
copper foams by a factor of 2 in comparison to the sponge replicated foams.Projekt DEAL 202
