Phase diagram investigation of the Cu–Sn system was carried out on twenty Cu-rich samples by thermal analysis (DTA), metallographic methods (EPMA/SEM-EDX) and crystallographic analysis (powder XRD, high temperature powder XRD). One main issue in this work was to investigate the high temperature phases beta (W-type) and gamma (BiF3-type) and to check the phase relations between them. In the high temperature powder XRD experiments the presence of the two-phase-field between the beta- and the gamma-phase could not be confirmed. Detailed study of primary literature together with our experimental results leads to a new phase diagram version with a higher order transformation between these two high temperature phases. The present work is designated as part I of our joint publication. The new findings described here have been included into a completely new thermodynamic assessment of the Cu–Sn phase diagram which is presented in part II.

中文翻译：

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Cu-Sn 相图，第一部分：新的实验结果

通过热分析 (DTA)、金相方法 (EPMA/SEM-EDX) 和晶体学分析 (粉末 XRD、高温粉末 XRD) 对 20 个富铜样品进行了 Cu-Sn 系统的相图研究。这项工作的一个主要问题是研究高温相 β（W 型）和 γ（BiF3 型）并检查它们之间的相关系。在高温粉末 XRD 实验中，无法确认 β 相和 γ 相之间存在两相场。对原始文献的详细研究以及我们的实验结果导致了在这两个高温相之间具有更高阶转变的新相图版本。目前的工作被指定为我们联合出版物的第一部分。