Adhesion, friction and tribochemical reactions at the diamond-silica interface
Adhesion, friction and tribochemical reactions at the diamond-silica interface
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DOI：
10.1016/j.carbon.2022.11.074
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发表时间：
2022-12-12
期刊：
影响因子：
10.9
通讯作者：
Righi, Maria Clelia
中科院分区：
文献类型：
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作者：
Cutini, Michele;Forghieri, Gaia;Righi, Maria Clelia
金刚石基涂层由于其出色的机械性能、生物相容性和化学稳定性而被用于多种技术应用中。重要的相关性是与氧化硅的界面，其中粘附、摩擦和磨损的现象可以显著地影响涂层的性能。在这里，我们实时监测这样的现象，在摩擦学条件下进行大规模从头算分子动力学模拟。我们考虑了许多相关因素，可以发挥作用，即金刚石表面取向和重建，硅烷醇密度，以及钝化物种的类型和浓度。大的系统尺寸和长的模拟时间，使我们的工作处于目前完全从头算分子动力学所能做的前沿。我们的工作结果表明，氢化作为一种有效的方法，以减少摩擦和磨损的所有金刚石表面，而石墨化是有竞争力的，只有在（111）表面。总的来说，我们希望我们的观察将有助于改善二氧化硅-金刚石界面起关键作用的技术应用。此外，我们证明了现实和准确的硅实验是可行的，现在利用HPC资源和HPC优化软件，铺平了道路，更全面地了解表面化学和纳米尺度摩擦学之间的关系。
Diamond-based coatings are employed in several technological applications, for their outstanding mechanical properties, biocompatibility, and chemical stability. Of significant relevance is the interface with silicon oxide, where phenomena of adhesion, friction, and wear can affect drastically the performance of the coating. Here we monitor such phenomena in real-time by performing massive ab initio molecular dynamics simulations in tribological conditions. We take into account many relevant factors that can play a role, i.e. the diamond surface orientation and reconstruction, silanol density, as well as, the type and concentration of passivating species. The large systems size and the long simulations time, put our work at the frontier of what can be currently done with fully ab initio molecular dynamics. The results of our work point to hydrogenation as an effective way to reduce both friction and wear for all diamond surfaces, while graphitization is competitive only on the (111) surface. Overall we expect that our observations will be useful to improve technological applications where the silica-diamond interface plays a key role. Moreover, we demonstrate that realistic and accurate in silico experiments are feasible nowadays exploiting HPC resources and HPC-optimized software, paving the way to a more general understanding of the relationship between surface chemistry and nanoscale-tribology.