The precise solubility data of a component in high-temperature melts are essential for the design and optimization of various processes including pyrometallurgical and solution growth processes. In this study, we developed an in situ method for measuring the solubility of a component in molten metals and alloys and investigated C solubility in molten Si using a system comprising Si and SiC substrate. The three-dimensional interfacial shape between the SiC substrate and molten Si droplet was analyzed from images captured by interferometry utilizing the internal interference in the SiC substrate. From the changes in interfacial shape, the temperature dependence of C solubility in molten Si up to 1873 K was successfully evaluated in the single experiment. The obtained C solubilities were in accordance with the smallest solubilities ever reported, suggesting a reliable evaluation because overestimations sometimes happen in the conventional point-by-point measurements of quenching samples. In addition, the excess partial molar Gibbs energy of C in molten Si was evaluated thermodynamically. The proposed method enables the in situ and crucible-free quantitative analysis of the solubility of a component in molten metals and alloys in the order of a few tens to hundreds of ppm for various material systems at high temperatures.

高温熔体中组分的精确溶解度数据对于包括火法冶金和溶液生长过程在内的各种工艺的设计和优化至关重要。在这项研究中，我们开发了一种原位测量组分在熔融金属和合金中的溶解度的方法，并使用包含 Si 和 SiC 衬底的系统研究了 C 在熔融 Si 中的溶解度。利用 SiC 衬底中的内部干涉，从干涉测量法捕获的图像中分析 SiC 衬底和熔融硅液滴之间的三维界面形状。从界面形状的变化来看，C 在熔融硅中的溶解度高达 1873 K 的温度依赖性在单个实验中被成功评估。获得的 C 溶解度与有史以来最小的溶解度一致，表明评估可靠，因为在淬火样品的传统逐点测量中有时会发生高估。此外，从热力学上评估熔融硅中 C 的过量偏摩尔吉布斯能。所提出的方法使对高温下各种材料系统的组分在熔融金属和合金中的溶解度的原位和无坩埚定量分析，溶解度为几十到几百 ppm。