ECR离子照射可控制造纳米结构碳膜及其摩擦特性研究

发布时间：2018-11-26 12:28

【摘要】：随着机械工程技术的发展,人们对零件的耐磨性和低摩擦特性要求不断提高,而纳米表面涂层技术是改善零件表面性能最简单最直接的方法。纳米涂层不仅能够进一步提高零件的低摩擦和耐磨特性,而且能够保持零件基体的高韧性,是目前表面防护和功能涂层技术领域的研究热点。石墨烯已经被证明是一种极好的固体润滑剂材料,当纳米石墨烯晶体嵌入碳膜中,纳米石墨烯晶体将对碳膜涂层的摩擦行为产生显著影响,因此,通过调控碳膜中嵌入的石墨烯结构可以使纳米碳膜达到极低的摩擦系数,对改善纳米碳膜的摩擦磨损特性具有重要研究意义。针对以上研究背景,我们开展了“ECR离子照射可控制造纳米结构碳膜及其摩擦特性研究”的工作。本研究利用ECR电子回旋共振中的发散型磁场离子照射进行加工。首先,改变电子回旋共振等离子体溅射系统中的基片偏压、微波功率和工作气压控制离子照射能量和密度。利用朗缪尔探针对等离子体进行诊断发现:离子照射能量随基片偏压增加而增加,离子照射密度随功率的增加而增加。通过调节离子照射能量和密度,可控制造纳米结构碳膜。利用透射电子显微镜(TEM),拉曼光谱和原子力显微镜(AFM)来表征纳米碳膜中的纳晶尺寸和表面粗糙度。实验结果表明,离子照射能够形成石墨烯纳米结构。离子照射密度增加和离子照射能量的减少会致使碳膜中含有的石墨烯晶粒尺寸变大。离子照射加工碳膜的表面光滑,表面粗糙度随照射能量和密度变化较小,在0.1nm左右。最后,利用球盘式摩擦磨损试验机对碳膜摩擦特性进行评价,得到碳膜的摩擦系数在0.07~0.13内变化,并且摩擦系数随着石墨烯晶粒尺寸的增加而降低。石墨烯纳晶结构碳膜展现出良好的耐磨特性,摩擦寿命在10000圈以上。为了阐明石墨烯纳晶碳膜的摩擦机理,通过高分辨金相显微镜和拉曼光谱对碳膜磨痕表面和对磨件氮化硅球的表面进行了表征分析。澄清了在相同条件下石墨烯纳晶碳膜低摩擦的机理是在摩擦接触界面形成3nm左右的石墨烯纳晶转移膜,同时接触面积较小使界面剪切强度降低。
[Abstract]:With the development of mechanical engineering technology, the requirements of wear resistance and low friction properties of the parts are constantly improved, and nano-surface coating technology is the simplest and most direct method to improve the surface properties of parts. Nanocrystalline coating can not only improve the low friction and wear resistance of the parts, but also maintain the high toughness of the substrates. It is a hot spot in the field of surface protection and functional coating technology. Graphene has been proved to be an excellent solid lubricant. When nano-graphene crystals are embedded in carbon films, nano-graphene crystals will have a significant effect on the friction behavior of carbon film coatings. By regulating the structure of graphene embedded in the carbon film, the friction coefficient of the nano-carbon film can reach a very low level, which is of great significance in improving the friction and wear characteristics of the nano-carbon film. In view of the above research background, we have carried out the work of "ECR Ion irradiation controlled Fabrication of Nanostructured carbon Films and their tribological Properties". In this study, ECR electron cyclotron resonance (ECR) was fabricated by irradiation of divergent magnetic field ions. Firstly, the substrate bias, microwave power and working pressure in the electron cyclotron resonance plasma sputtering system are changed to control the energy and density of ion irradiation. Using Langmuir probe to diagnose the plasma, it is found that the ion irradiation energy increases with the increase of substrate bias, and the ion irradiation density increases with the increase of power. Nanostructured carbon films can be produced by adjusting the energy and density of ion irradiation. The nanocrystalline size and surface roughness were characterized by transmission electron microscopy (TEM) (TEM), Raman spectroscopy and atomic force microscope (AFM). The experimental results show that the graphene nanostructures can be formed by ion irradiation. The increase of ion irradiation density and the decrease of ion irradiation energy will increase the grain size of graphene in carbon film. The surface of carbon film prepared by ion irradiation is smooth, and the surface roughness changes slightly with the irradiation energy and density, about 0.1nm. Finally, the friction characteristics of carbon film were evaluated by ball disk friction and wear tester. The friction coefficient of carbon film varied within 0.07 ~ 0.13, and the friction coefficient decreased with the increase of graphene grain size. Graphene nanocrystalline carbon film shows good wear resistance and its friction life is more than 10000 circles. In order to elucidate the friction mechanism of graphene nanocrystalline carbon film, the wear surface of carbon film and the surface of silicon nitride ball were characterized by high resolution metallographic microscope and Raman spectroscopy. It is clarified that the mechanism of low friction of graphene nanocrystalline carbon film under the same conditions is that the graphene nanocrystalline transfer film about 3nm is formed at the frictional contact interface, and the interface shear strength is decreased when the contact area is small.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4

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