高周波グロー放電発光分析法を用いた鉄固溶体におけるホウ素の固溶限測定

• Published in: 鉄と鋼 Vol. 106; no. 6; pp. 292 - 301
• Main Authors: 宮城, 俊美, 木村, 勇太, 関戸, 信彰, 小山内, 匠, 吉見, 享祐, 沼倉, 宏
• Format: Journal Article
• Language: Japanese
• Published: 一般社団法人 日本鉄鋼協会 2020
• Subjects: boron; diffusion-couple method; phase diagram; radio-frequency glow-discharge optical emission spectroscopy; solubility
• ISSN: 0021-1575; 1883-2954
• DOI: 10.2355/tetsutohagane.TETSU-2019-114

The solubility of boron in α- and γ-iron solid solutions was investigated by diffusion-couple experiments in the Fe-B, Fe-Ni-B, and Fe-Si-B systems. Diffusion couples composed of iron foils and Fe2B bulk specimens were annealed at various temperature between 750ºC and 1100ºC, and the concentration profile of boron from the end-surface of the iron part were measured by the radio-frequency glow-discharge optical emission spectroscopy (rf-GD-OES). It was found that rf-GD-OES was effective in analyzing boron of low concentrations in iron. The solubility limit of boron in α- and γ-iron determined by analyzing the concentration profiles in the diffusion couples was found to agree with that reported by Cameron and Morral for α-iron, and that by Brown et al. for γ-iron. It was also suggested that the invariant reaction between α-iron, γ-iron and Fe2B was a eutectoid reaction, as had been indicated by Cameron and Morral.