Atomic-level wear behavior of sliding between silica (010) surfaces
Atomic-level wear behavior of sliding between silica (010) surfaces
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DOI：
10.1016/j.apsusc.2017.07.055
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发表时间：
2017-12-15
影响因子：
6.7
通讯作者：
Duan, Fang-Li
中科院分区：
文献类型：
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作者：
Wang, Ming;Duan, Fang-Li
反应分子动力学（ReaxFF）模拟被用来寻找原子级磨损机制发生在完全羟基化的二氧化硅（010）作为界面水量的函数的滑动界面。结果表明，表面硅氧烷键的断裂行为有两种。一种是由表面硅氧烷键和水之间的水解反应产生的。另一种也是由水解反应引起的，但由界面硅氧烷键辅助。这两种断裂行为直接导致二氧化硅表面的摩擦化学磨损。在小于一个完整的单层水的存在下，仅由水解反应引起的磨损程度的影响，由增加的水分子引起的界面剪切作用的变化。然而，由界面硅氧烷键辅助的磨损程度与界面水在界面硅氧烷键中的双重作用有关。还应注意，摩擦化学磨损的发生是由界面硅氧烷键的形成引起的，其与载荷相关的概率范围为18%至37%。此外，机械磨损，其特征在于在次表面的局部晶格畸变，也观察到在我们的模拟。这项研究表明，即使没有界面硅氧烷键形成，二氧化硅的摩擦化学磨损仍然可以发生由于应力腐蚀，并提供了进一步的见解二氧化硅的磨损机理。(C)2017 Elsevier B.V.版权所有。
Reactive molecular dynamics (ReaxFF) simulations were used to find the atomic-level wear mechanisms occurring at the sliding interface of fully hydroxylated silica (010) as a function of an interfacial water amount. The results showed that there were two kinds of rupture behaviors of surface siloxane bonds. One is resulted from only hydrolysis reaction between surface siloxane bonds and water. The other is also caused by the hydrolysis reaction, but is assisted by the interfacial siloxane bonds. Both rupture behaviors directly lead to tribochemical wear on silica surfaces. In the presence of less than a full monolayer water, the degree of wear induced only by hydrolysis reaction is affected by the change of interfacial shearing actions caused by increasing water molecules. However, the degree of wear assisted by interfacial siloxane bonds is related to the dual role of interfacial water in interfacial siloxane bonds. It is also noted that the load-dependent probability that the occurrence of tribochemical wear is caused by the formation of an interfacial siloxane bond ranges from 18% to 37%. In addition, mechanical wear, characterized by the local lattice distortion at subsurface, was also observed in our simulations. This study shows that even though no interfacial siloxane bond is formed, tribochemical wear of silica can still occur due to stress corrosion, and provides further insights into the wear mechanism of silica. (C) 2017 Elsevier B.V. All rights reserved.