Xia Xinsheng, Van Hoesen D C, McKenzie Matthew E, Youngman Randall E, Kelton K F
Institute of Materials Science and Engineering, Washington University, St. Louis, 63130, MO, USA.
Department of Physics, Washington University, St. Louis, 63130, MO, USA.
Nat Commun. 2021 Apr 1;12(1):2026. doi: 10.1038/s41467-021-22161-9.
For over 40 years, measurements of the nucleation rates in a large number of silicate glasses have indicated a breakdown in the Classical Nucleation Theory at temperatures below that of the peak nucleation rate. The data show that instead of steadily decreasing with decreasing temperature, the work of critical cluster formation enters a plateau and even starts to increase. Many explanations have been offered to explain this anomaly, but none have provided a satisfactory answer. We present an experimental approach to demonstrate explicitly for the example of a 5BaO ∙ 8SiO glass that the anomaly is not a real phenomenon, but instead an artifact arising from an insufficient heating time at low temperatures. Heating times much longer than previously used at a temperature 50 K below the peak nucleation rate temperature give results that are consistent with the predictions of the Classical Nucleation Theory. These results raise the question of whether the claimed anomaly is also an artifact in other glasses.
四十多年来，对大量硅酸盐玻璃中成核速率的测量表明，在低于峰值成核速率的温度下，经典成核理论出现了失效。数据显示，临界团簇形成功并非随着温度降低而稳步下降，而是进入一个平稳期，甚至开始增加。人们提出了许多解释来解释这种异常现象，但都没有给出令人满意的答案。我们提出了一种实验方法，以5BaO∙8SiO玻璃为例明确证明，这种异常现象并非真实存在，而是低温下加热时间不足导致的假象。在比峰值成核速率温度低50K的温度下，采用比以前长得多的加热时间，得到的结果与经典成核理论的预测一致。这些结果引发了一个问题，即其他玻璃中声称的异常现象是否也是一种假象。
