Formation of Sm-Fe Intermetallic Compounds by the Reduction-Diffusion process
In order to clarify the rate and mechanism of the formation of Sm-Fe intermetallic compounds by the reduction-diffusion (R-D) process, three kinds of experiments were carried out:(1) the reduction of pellets of Sm203 powder mixed with CaH2, (2) the R-D reaction for the pellets which were composed of...
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Veröffentlicht in: | Shigen to sozai 1992/02/25, Vol.108(2), pp.95-101 |
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Format: | Artikel |
Sprache: | eng ; jpn |
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Zusammenfassung: | In order to clarify the rate and mechanism of the formation of Sm-Fe intermetallic compounds by the reduction-diffusion (R-D) process, three kinds of experiments were carried out:(1) the reduction of pellets of Sm203 powder mixed with CaH2, (2) the R-D reaction for the pellets which were composed of Sm2O3, CaH2 and Fe (powder or wire) at 1, 300, 1, 400 and 1, 500K, and (3) diffusion experiment by using Sm-Fe diffusion couples with Mo wire as a marker at 963K. The reduction of Sm2O3 uniformly proceeded in the pellets; more than 90% of Sm2O3 was reduced at 1, 400 and 1, 500K in a reaction time less than 1 ks, though about 80% at 1, 300 K at a reaction time of 1 ks. During the R-D reaction, an Sm2Fe17 layer was formed on the Fe surface. The thickness of the Sm2Fe17 layer grew according to a parabolic rate law at 1, 300K. At 1, 400 and 1, 500K, however, the Fe dissolved in a liquid Sm or Sm-Ca melt, since the reduction rate of Sm2O3 was high. The experiment with the diffusion couple revealed that Fe diffused faster than Sm in the SmFe2 layer. |
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ISSN: | 0916-1740 1880-6244 |
DOI: | 10.2473/shigentosozai.108.95 |