Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures
Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures
复制标题
由 SiC 自生成的三个摩擦层分别用于减少不同接触压力下的摩擦
DOI：
10.1021/acs.jpcc.1c07668
复制
发表时间：
2022
期刊：
影响因子：
3.7
通讯作者：
M. Kubo
中科院分区：
文献类型：
--
作者：
Y. Ootani;J. Xu;F. Nakamura;M. Kawaura;S. Uehara;Y. Wang;N. Ozawa;K. Adachi;M. Kubo
碳化硅（SiC）/水系统的低摩擦被理解为是通过摩擦化学反应产生的自形成二氧化硅基摩擦层的结果。虽然一些实验研究表明，这种基于二氧化硅的摩擦层含有大量的碳，但摩擦层的详细结构及其在提供低摩擦方面的作用仍不清楚。在这里，我们进行了反应分子动力学滑动模拟的非晶SiC（a-SiC）/水系统，以阐明原子尺度的结构的自形成摩擦层及其形成的机制。我们发现，水选择性地氧化在a-SiC的表面的Si原子，导致其去除的SiO2磨损颗粒。其中一些磨损颗粒溶解在水中，导致形成胶体二氧化硅，而另一些则沉积在a-SiC表面，在那里形成一层二氧化硅水合物。同时，碳原子保留在a-SiC表面并形成富C层，这对应于非晶碳层形成的初始过程。基于我们的研究结果，我们提出，胶体二氧化硅，二氧化硅水合物，和无定形碳作为单独的摩擦层，以减少摩擦，在低，中，高接触压力的地区，分别。在低接触压力区域，水主要分离表面，并且二氧化硅水合物由于其高亲水性而将水保持在滑动界面处，从而增加水的承载能力。在中等接触压力区域，水不能分离表面，但胶态二氧化硅层可以，因为它的高粘度。在高接触压力区域，水和硅基层被破坏，无定形碳层作为固体润滑剂。因此，三个自形成摩擦层一起产生SiC/水系统所特有的低摩擦。
The low friction of silicon carbide (SiC)/water systems is understood to be the result of a self-forming silica-based tribolayer that is produced by tribochemical reactions. Although several experimental studies have revealed that this silica-based tribolayer contains a considerable amount of carbon, the detailed structure of the tribolayer and its role in providing low friction remain unclear. Here, we conducted a reactive molecular dynamics sliding simulation of an amorphous SiC (a-SiC)/water system to elucidate the atomic-scale structure of the self-forming tribolayer and the mechanism underlying its formation. We found that the water selectively oxidized Si atoms at the surface of the a-SiC, resulting in their removal as SiO2wear particles. Some of these wear particles dissolved in the water, resulting in the formation of colloidal silica, whereas others were deposited on the a-SiC surface, where they formed a layer of silica hydrate. Meanwhile, carbon atoms remained at the a-SiC surface and formed a C-rich layer, which corresponds to the initial process of an amorphous carbon layer formation. Based on our findings, we propose that colloidal silica, silica hydrate, and amorphous carbon act as individual tribolayers to reduce friction in the low-, intermediate-, and high-contact-pressure areas, respectively. In the low-contact-pressure area, water mainly separates the surfaces, and the silica hydrate holds the water at the sliding interface because of its high hydrophilicity, increasing the load-carrying capacity of the water. In the intermediate-contact-pressure area, the water cannot separate the surfaces, but the colloidal silica layer can because of its high viscosity. In the high-contact-pressure area, where the water and silica-based layers are broken, the amorphous carbon layer works as a solid lubricant. Thus, the three self-forming tribolayers together produce the low friction that characterizes SiC/water systems.
登录
查看更多内容
影响因子：
16.6
作者：
Berman D;Narayanan B;Cherukara MJ;Sankaranarayanan SKRS;Erdemir A;Zinovev A;Sumant AV
通讯作者：
Sumant AV
影响因子：
6.7
作者：
Wang, Ming;Duan, Fang-Li
通讯作者：
Duan, Fang-Li
通过微结构配方和固液润滑在真空下在 SiC 上实现低摩擦碳化物衍生碳涂层
DOI：
--
发表时间：
2014
期刊：
Tribology letter
影响因子：
--
作者：
Fuyan Liu;Hui Guo;Wen;J. Sui;Le Sun;Junhu Meng;Qihua Wang;Jin
通讯作者：
Jin
影响因子：
3.7
作者：
Ootani, Yusuke;Xu, Jingxiang;Kubo, Momoji
通讯作者：
Kubo, Momoji