Phase diagram of the Nd₂Fe₁₄B-Sm₂Fe₁₄B pseudo-binary system

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• 作者：Ch. F. Xu ; K. H. Chen ; Z. F. Gu ; L. Y. Cheng ; D. D. Ma ; G. Cheng ; G. H. Rao and Q. R. Yao
• 关键词：phase diagrams ; Nd2Fe14B&ndash ; Sm2Fe14B system ; X-ray powder diffraction ; differential thermal analysis
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：49
• 期：1
• 页码：64-68
• 全文大小：901K
• ISSN：1600-5767

文摘

The phase relations in the (1−x)Nd₂Fe₁₄B–xSm₂Fe₁₄B system over the whole concentration range have been studied by means of X-ray powder diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Crystal structure parameters for all studied compositions of (Nd_1−xSm_x)₂Fe₁₄B have been determined by full-profile Rietveld refinements. These results revealed that all intermediate alloys of (Nd_1−xSm_x)₂Fe₁₄B are similar to the end member of the investigated system, Nd₂Fe₁₄B, with a tetragonal structure (space group P4₂/mnm). The formation of continuous solid solutions has been found in this system. The normalized lattice parameters and unit-cell volumes of (Nd_1−xSm_x)₂Fe₁₄B solid solutions decrease linearly with increasing Sm content. The DTA measurements show that the melting temperature of (Nd_1−xSm_x)₂Fe₁₄B increases linearly with increasing Sm content and no metastable phases were detected. Based on the DTA data and XRD results, a tentative phase diagram for the pseudo-binary system Nd₂Fe₁₄B–Sm₂Fe₁₄B has been constructed.