The detailed analysis of newly found concentration fluctuations near the eutectic point in the homogeneous liquid phase of eutectic systems

本研究者发现在共晶系统的均相液相中，在共晶点附近存在浓度波动。本研究的目的是建立这种浓度涨落的严格证据，并提出详细的看法，在Spring-8的液态深共晶系统，Au-Ge的EXAFS实验，显示了这种浓度涨落的存在的一些证据。“深共晶系统”，Au-Si，Au-Ge，Ag-Si，Ag-Ge系统的电阻率的精确测量显示了大的浓度波动，其量为7体积%。对液态“多共晶点共晶系统”的精确电阻率测量表明，在均匀液相中，每一个共晶组分周围都有异常行为。共晶成分均匀液相中的浓度波动可能表现为微观预凝固现象。这 关于我们 这意味着均匀液体的过冷倾向在低共熔组成下必须最小。这一观点与普遍认为的共晶液体具有最大的过冷倾向和玻璃形成能力的观点不同。通过对以往文献中关于某些共晶系均匀过冷现象的分析，发现在共晶成分处，均匀液相的过冷倾向最小。因此，本文通过DSC实验研究了Au-Ge液态深共晶体系的过冷行为。当然，过冷趋势是最小的共晶成分。这有力地支持了在均匀液相中低共熔组合物周围存在浓度波动。今后，详细的结构分析必须通过大规模的计算机模拟来进行。必须确认的是，在离子液体、水溶液等多种共晶液体中，均相液相中的共晶组分周围普遍存在浓度波动。

The present investigator has found the existence of concentration fluctuations near the eutectic point in the homogeneous liquid phase of eutectic systems. The purposes of this research program are to establish the rigorous evidences for this concentration fluctuation and to present the detailed view about it. The EXAFS experiment in the Spring-8 for liquid deep eutectic system, Au-Ge, showed some evidence for the existence of such a concentration fluctuation. The precise measurements of electrical resistivity for "deep eutectic systems", Au-Si, Au-Ge, Ag-Si, Ag-Ge systems, showed the large concentration fluctuations, which amounts to 7 vol.%. The accurate electrical resistivity measurements for liquid "eutectic systems with multi eutectic points" showed an anomalous behavior around every eutectic composition in homogeneous liquid phases. The concentration fluctuation in the homogeneous liquid phase of eutectic composition may appear as the microscopic presolidification phenomena. This … More implies that the supercooling tendency of homogeneous liquids must be smallest at the eutectic composition. This proposal is different from the prevailing common sense about the eutectic liquids, which tells us that the eutectic liquid has the largest supercooling tendency and glass forming ability. The analysis of previous literatures about the homogeneous supercooling in some eutectic systems showed that the supercooling tendency of homogeneous liquid phase is smallest at the eutectic composition. Therefore, the supercooling behavior was investigated by the DSC experiments for liquid deep eutectic system, Au-Ge. Surely the supercoling tendency is smallest at the eutectic composition. This strongly supports the existence of concentration fluctuations around the eutectic composition in the homogeneous liquid phase. In future, the detailed structure analysis must be performed by the large scale computer simulations. It must be confirmed that the concentration fluctuations exist around the eutectic composition in the homogeneous liquid phase universally in various eutectic liquids of many kinds, such as ionic liquids, water solutions, etc. Less