Department of Control Engineering, Faculty of Electrical Engineering , Czech Technical University in Prague , Karlovo námestí 13 , 121 35 Prague 2 , Czech Republic.
Istituto Italiano di Tecnologia-IIT , Via Morego 30 , 16163 Genova , Italy.
ACS Appl Mater Interfaces. 2018 Mar 14;10(10):8937-8946. doi: 10.1021/acsami.7b17960. Epub 2018 Mar 1.
Molybdenum disulfide (MoS) is a well-known and effective lubricant that provides extremely low values of coefficient of friction. It is known that the sliding process may induce structural transformations of amorphous or disordered MoS to the crystalline phase with basal planes oriented parallel to the sliding direction, which is optimal for reducing friction. However, the key reaction parameters and conditions promoting this structural transformation are still largely unknown. We investigate, by employing reactive molecular dynamics simulations, the formation of MoS layers from an amorphous phase as a function of temperature, initial sample density, and sliding velocity. We show that the formation of ordered crystalline structures can be explained in the framework of classical nucleation theory as it predicts the conditions for their nucleation and growth. These results may have important implications in the fields of coating and thin-film deposition, tribology, and in all technological applications where a fast and effective structural transition to an ordered phase is needed.
二硫化钼（MoS）是一种众所周知且有效的润滑剂，其摩擦系数极低。已知滑动过程可能会导致非晶态或无序 MoS 转变为具有基面平行于滑动方向的晶相，这对于降低摩擦是最理想的。然而，促进这种结构转变的关键反应参数和条件在很大程度上仍然未知。我们通过使用反应分子动力学模拟，研究了在温度、初始样品密度和滑动速度的作用下，非晶相形成 MoS 层的过程。我们表明，有序晶体结构的形成可以用经典成核理论来解释，因为它预测了它们成核和生长的条件。这些结果在涂层和薄膜沉积、摩擦学以及所有需要快速有效地向有序相转变的技术应用领域中可能具有重要意义。
