Method for the preparation of a spongy metallic body

摘要

The invention provides an improved method for the preparation of a porous spongy body of a metal or alloy having an open cell structure. The basic principle of the method is the pressurized casting of a melt of the metal or alloy with a preheated powder compact of an inorganic compound soluble in a solvent to fill up the pores and dissolving away the inorganic compound with a solvent after solidification of the melt. The improvement comprises forming interconnections bridging the particles in the powder compact and, different from conventional methods in which the preheating temperature is higher than the solidification temperature of the melt, preheating the powder compact at a temperature lower than the solidification temperature of the melt but higher than a critical preheating temperature defined as a function of the solidification temperature of the melt, latent heat of solidification of the melt, density of the metal or alloy, volume fraction of the inorganic compound in the powder compact under casting, specific heat of the inorganic compound and true density of the inorganic compound.