Dinesh Kumar D, Hazra Subhenjit, Panda Kalpataru, Kuppusami Parasuram, Stimpel-Lindner Tanja, Duesberg Georg S
Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India.
Centre of Excellence for Energy Research, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India.
ACS Appl Mater Interfaces. 2022 Jun 8;14(22):26148-26161. doi: 10.1021/acsami.2c03043. Epub 2022 May 29.
Minimizing friction and wear is one of the continuing challenges in many mechanical industries. Recent research efforts have been focused on accelerating the antifriction and antiwear properties of hard coatings through the incorporation of self-lubricant materials or the development of new architectures. In this present study, carbon-rich MoC, MoCN, and multilayer MoC/MoCN coatings were deposited using reactive magnetron sputtering. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used to evaluate their properties, which revealed the presence of ceramic cubic crystallites, covalent bonds between primary elements, and an excess of amorphous carbon (a-C) in all of the coatings. The multilayer architecture and possible segregation of a-C around the ceramic crystallites resulted in improved mechanical properties for all coatings, with MoC/MoCN coatings having a maximum hardness of 21 GPa and elastic modulus of 236 GPa. Friction and wear behavior are initially determined by the structural-composition-property relationships of the respective coatings; later, the tribological characteristics are altered depending on the nature of tribolayer on both mating surfaces at the contact interface. The highest wear resistance of multilayer MoC/MoCN coating (8.7 × 10 mm/N m) and MoC coating (3.9 × 10 mm/N m) was due to the dissipation of contact stress by the tribofilm consisting of carbon tribo products like graphitic sp carbon, diamond-like sp carbon, and pyrrolic-N. On the other hand, MoCN coating depicted a lower wear resistance due to the frequent termination of C-H bonds by N, which restricts the strong formation of tribofilms as well as poor mechanical properties.
在许多机械行业中，将摩擦和磨损降至最低一直是持续存在的挑战之一。最近的研究工作集中在通过加入自润滑材料或开发新结构来提高硬涂层的减摩和抗磨性能。在本研究中，采用反应磁控溅射沉积了富碳的MoC、MoCN和多层MoC/MoCN涂层。利用X射线衍射（XRD）、X射线光电子能谱（XPS）和拉曼光谱对其性能进行了评估，结果表明所有涂层中均存在陶瓷立方微晶、主要元素之间的共价键以及过量的非晶碳（a-C）。多层结构以及a-C在陶瓷微晶周围可能的偏析导致所有涂层的机械性能得到改善，其中MoC/MoCN涂层的最大硬度为21 GPa，弹性模量为236 GPa。摩擦和磨损行为最初由各涂层的结构-成分-性能关系决定；随后，摩擦学特性会根据接触界面处两个配对表面上摩擦层的性质而改变。多层MoC/MoCN涂层（8.7×10⁻⁶ mm³/N·m）和MoC涂层（3.9×10⁻⁶ mm³/N·m）的最高耐磨性归因于由石墨化sp碳、类金刚石sp碳和吡咯-N等碳摩擦产物组成的摩擦膜对接触应力的耗散。另一方面，MoCN涂层的耐磨性较低，这是因为N频繁终止C-H键，限制了摩擦膜的强烈形成以及较差的机械性能。
