The neodymium-gold phase diagram
- Sezione di Chimica Inorganicae Metallurgia, Genova (Italy)
The Nd-Au phase diagram was studied in the 0 to 100 at. pct Au composition range by differential thermal analysis (DTA), X-ray diffraction (XRD), optical microscopy (LOM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Six intermetallic phases were identified, the crystallographic structures were determined or confirmed, and the melting behavior was determined, as follows: Nd{sub 2}Au, orthorhombic oP12-Co{sub 2}Si type, peritectic decomposition at 810 C; NdAu, R.T. form, orthorhombic oP8-FeB type, H.T. forms, orthorhombic oC8-CrB type and, at a higher temperature, cubic cP2-CsCl type, melting point 1470 C; Nd{sub 3}Au{sub 4}, trigonal hR42-Pu{sub 3}Pd{sub 4} type, peritectic decomposition at 1250 C; Nd{sub 17}Au{sub 36}, tetragonal tP106-Nd{sub 17}Au{sub 36} type, melting point 1170 C; Nd{sub 14}Au{sub 51}, hexagonal hP65-Gd{sub 14}Ag{sub 51} type, melting point 1210 C; and NdAu{sub 6}, monoclinic mC28-PrAu{sub 6} type, peritectic decomposition at 875 C. Four eutectic reactions were found, respectively, at 19.0 at. pct Au and 655 C, at 63.0 at. pct Au and 1080 C, at 72.0 at. pct Au and 1050 C, and, finally, at 91.0 at. pct Au and 795 C. A catatectic decomposition of the ({beta}Nd) phase, at 825 C and {approx}1 at. pct Au, was also found. The results are briefly discussed and compared to those for the other rare earth-gold (R-Au) systems. A short discussion of the general alloying behavior of the coinage metals (Cu, Ag, and Au) with the rare-earth metals is finally presented.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 363977
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 5 Vol. 30; ISSN MMTAEB; ISSN 1073-5623
- Country of Publication:
- United States
- Language:
- English
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