Exploring the low friction of diamond-like carbon films in carbon dioxide atmosphere by experiments and first-principles calculations
Exploring the low friction of diamond-like carbon films in carbon dioxide atmosphere by experiments and first-principles calculations
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通过实验和第一性原理计算探索类金刚石碳膜在二氧化碳气氛中的低摩擦性能
DOI：
10.1016/j.apsusc.2017.12.044
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发表时间：
2018-04-01
影响因子：
6.7
通讯作者：
Wang, Liping
中科院分区：
文献类型：
--
作者：
Huo, Lei;Wang, Shunhua;Wang, Liping
DLC膜在CO2气氛中的摩擦行为及其机理研究较少，这是制约DLC膜在CO2环境中应用的重要因素。在这里，实验和第一性原理计算进行同时调查这一主题。我们发现，DLC膜在CO2气氛中表现出惊人的低摩擦系数相比，在环境空气和真空气氛。XPS和拉曼光谱分析表明，在剪切界面处可能存在CO2分子的活化，这可能是DLC膜在CO2气氛中获得低摩擦的关键。计算结果表明，CO2分子在DLC表面的水平化学吸附过程中容易形成内酯基团，这种吸附过程是一个高能的过程，在界面应力的作用下是一个有利的过程。由于内酯基团的孤对的存在，内酯封端的表面似乎是负责在CO2气氛中的DLC膜的低摩擦。这些研究可能为DLC薄膜在火星应用中的应用开辟了可能性。(C)2017爱思唯尔B.V.保留所有权利。
The friction behavior and the mechanism of DLC films in CO2 atmosphere are rarely explored, which is a significant obstacle for the potential practical application of DLC films in primarily CO2 environment. Here, the experiments and first-principles calculations are performed to simultaneously investigate this theme. We find that DLC films in CO2 atmosphere exhibit astoundingly low friction coefficient compared with in ambient air and vacuum atmospheres. The XPS and Raman spectrums demonstrate the possibly activation of CO2 molecule in the shearing interfaces, which may be critical for the low friction of DLC films in CO2 atmosphere. The calculated results reveal that the lactone groups can easily form during the horizontally chemisorption of CO2 molecule on the DLC surface, which is energetic and is a favorable process under the interfacial stress. Because of the presence of the lone-pairs of the lactone group, the lactone-terminated surfaces appear to be responsible for the low friction of DLC films in CO2 atmosphere. The studies may open up the possibility for DLC films usage in Mars applications. (C) 2017 Elsevier B.V. All rights reserved.