Melting temperatures of Sn-Ag-Cu (SAC) alloys in the Sn-rich corner are of interest for lead-free soldering. At the same time, nanoparticle solders with depressed melting temperatures close to the Sn-Pb eutectic temperature have received increasing attention. Recently, the phase stability of nanoparticles has been the subject of plenty of theoretical and empirical investigations. In the present study, SAC nanoparticles of various sizes have been synthesized via chemical reduction and the size dependent melting point depression of these particles has been specified experimentally. The liquidus projection in the Sn-rich corner of the ternary SAC system has also been calculated as a function of particle size, based on the CALPHAD-approach. The calculated melting temperatures were compared with those obtained experimentally and with values reported in the literature, which revealed good agreement. The model also predicts that with decreasing particle size, the eutectic composition shifts towards the Sn-rich corner.

中文翻译：

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Sn-Ag-Cu纳米焊料：在三元系统的富Sn角中的熔融行为和相图预测。

对于无铅焊接，在富锡拐角处的Sn-Ag-Cu（SAC）合金的熔化温度非常重要。同时，熔化温度降低到接近Sn-Pb共晶温度的纳米颗粒焊料受到越来越多的关注。近来，纳米颗粒的相稳定性已成为大量理论和经验研究的主题。在本研究中，已通过化学还原合成了各种尺寸的SAC纳米粒子，并通过实验确定了这些粒子的尺寸依赖性熔点降低。基于CALPHAD方法，还计算了三元SAC系统中富Sn角的液相线投影与粒径的关系。将计算出的熔融温度与通过实验获得的熔融温度进行比较，并与文献中报道的值进行比较，这表明一致性良好。该模型还预测，随着粒径的减小，共晶成分会向富锡角移动。