Abstract
Although ceramic particle additives in precursor metallic powder compacts may be effective to avoid the collapse of the foams during the heating process, the excessive addition seems to disturb the expansion itself. To establish a method of stabilizing foam structures without losing foamability of the precursor, the effects of granulating SiC particles before addition to the compacts were examined for A1Si7. By adding SiC powder in the form of granules, the limit of SiC contents due to the drop in expansion was extended. The graded foaming of precursor with three-layer structures was also performed with SiC granules. The stability as well as the foamability of the layered foams was increased, and the effectiveness of granulating SiC particles on the graded foaming was confirmed.
