Preparation of Metallic Porous Materials by Oxide-Reduction Liquid Phase Sintering of Fe-SnO₂ Mixture

Abstract

Green compacts of mixture of iron and tin oxide powders were heated at 773–973 K in a hydrogen atmosphere to produce a metallic porous material. Tin oxide in a green compact was not reduced sufficiently to tin after 3.6×10³ s at 673 K. Even at 773 K, some tin oxide was not reduced to tin by reduction after 3.6×10³ s. At 873 K, a sintered body with sufficient strength was obtained using the reduction processing for 3.6×10³ s, and fine FeSn crystals were generated on the iron powder surface. The compression strength of the sintered body obtained at 873 K was 45.1 MPa. It was confirmed that the FeSn crystals connected the each iron powder particles. At 973 K, although a sintered body was obtained, it had low strength because the FeSn on the iron powder surface grew to form large crystals. Results demonstrated that the open porous metal can be manufactured through tin-oxide reduction liquid phase sintering for 3.6×10³ s at 873 K.