レア・アース・メタル処理鋳鉄溶湯中への黒鉛の成長について

抄録

  Interfacial energies between molten iron containing rare earth metals and specific planes of graphite crystal were measured using the sessile drop technique. And Ni-C alloy sticks with spheroidal or flaky graphite structure were put into molten irons treated and untreated with rare earth metal. Graphite grows from the graphite in the stick into molten iron. Condensation of Ce only increases the international energy of molten iron/prism plane of graphite in the similar manner of Mg-treated iron. Single crystalline flake graphite is more stable than polycrystalline in irons containing less Ce, while polycrystalline spheroidal graphite is more stable in irons containing more of Ce on the basis of interfacial free energy ratio. Graphite grows into molten iron in the form of spheroid, C/V or flake depending on properties of molten iron regardless of the shape of graphite substrates. The graphite morphology depends on the interfacial energy of molten iron/specific planes of graphite.