センパーム合金に現われる3元化合物σ相の結晶構造について

抄録

In the previous papers, it was reported that in alloys of Fe-Ni-Si system a ferromagnetic ternary compound σ-phase is formed and its chemical formula is inferred to be Fe₁₁Ni₅Si₄ (60.2%Fe, 28.8%Ni, 11.0%Si). In the present paper, the crystal structure of this σ-phase has been studied by X-ray diffraction technique with powder camera and Geiger-counter spectrometer. Through interpretation of powder-pattern photographs and recording charts, as well as measurement of density of an alloy almost consisting of σ-phase by pycnometer method, the following results have been obtained: (1) The σ-phase has crystal structure of simple cubic type with lattice parameter a₀=6.148 Å. (2) Its measured density is 7.30 g/cc (at 17°C). (3) It contains 20 atoms, or one molecule of Fe₁₁Ni₅Si₄ in its unit cell.