New Manufacturing Method of lron Foam using Precursor Made of Iron, Graphite and Hematite Powders

摘要

Iron based metal foam has several advantages over aluminum alloy foam such as high strength, high energy absorbability and low cost. However, it is hard to manufacture iron foam using conventional foaming agents because of a significant difference between their decomposition temperatures and melting point of iron. In this study, a new manufacturing method of iron foam in use of CO and CO_2 gases as foaming agents was studied, which was generated by reduction of iron oxide by carbon contained in iron melt. In this method, the cold-pressed precursor made of pure iron, graphite and hematite powders is heated at temperatures between solidus and liquidus in Fe-C binary system. The powder size and the amount of hematite used to make a precursor markedly affected the porosity and pore size of iron foam. Iron foam with the porosity of approximately 55 percent was obtained using the precursor with the composition of Fe-3.1 percent C-10 percent Fe_2O_3.