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传统上，低摩擦和耐磨材料的开发是由高度特定的工业应用驱动的，例如加工，冲压和形成工具[1]。亚博网站下载现在，这些涂料也在更广泛的产品中产生影响，包括剃须刀，磁性硬盘，关键发动机零件，机械面部密封，耐刮擦的玻璃，侵入性和可植入的医疗设备以及微电力机械系统（MEMS）[2] [2]。
Low-friction, low-wear and anti-adhesion properties are the highly desirable characteristics of these coatings, which include diamond-like carbon (DLC) coatings as well as nanostructured metal nitrides, such as molybdenum nitride and titanium nitride [2][3]. Nanocomposite coatings are now becoming commonplace for the protection of the contact surfaces of mechanical systems as they allow higher speeds, increase lifetime, and improve corrosion resistance [1][2].
钻石状碳涂料（DLC）
许多DLC膜非常硬，并且提供了接近90 gigapascals（GPA）的硬度数据。超硬材料的定义为40 亚博网站下载GPA的硬度[4]。同时，从摩擦学的角度来看，它们提供了一些最低的已知摩擦和磨损系数。
出色的光学和电气性能以及酸性和盐水介质中腐蚀性和氧化攻击的化学惰性使DLC独特。了解动态润滑机制在DLC表面运行的方式仍处于起步阶段，并且已经假定研究来检查DLC和润滑剂之间的化学相互作用如何影响摩擦学[3] [5]。一些研究人员认为，氢钝化了DLC表面上的“悬挂键”，以降低摩擦系数。尽管其他研究研究了DLC与水的相互作用，并提出亲水性羟基在减少DLC表面的摩擦中起作用。可以得出结论，DLC表面上未被广告的Sigma和PI键的存在是摩擦增加的主要原因[3]。
酒精和脂肪酸相互作用
2013年的一项研究检查了使用原子力显微镜（AFM）和摩擦学测试的六烷醇与DLC表面的相互作用。AFM表示表面覆盖量，即酒精分子吸附岛的大小和密度。然后进行摩擦学测试，将磨损和摩擦行为与表面上的分子吸附相关。该研究表明，醇在物理和化学上都吸附在DLC表面上，并且很可能充当DLC涂层的边界润滑化合物。酒精吸附到DLC表面上可以减少涂层的磨损，但在进一步减少DLC的摩擦方面的有效性较小。提出的吸附机制暗示了温度效应和摩擦摩擦效应，并表明DLC表面和羟基氢之间的氧化物之间的键合成氧化物，因此长长的烷氧基链（Hexyl）链向外朝外并能够参与润滑过程。
酒精以其润滑特性而闻名[3]。一项研究[6]比较了DLC上己二烷酸和己醇的吸附特性，表明酒精和脂肪酸都可以为DLC表面提供磨损保护，尤其是在80°C以上的温度下。同样，由于DLC涂层的固有低摩擦特性，摩擦均无原来的减少。但是，与醇相比，在低浓度（2至5 mmol/L）的脂肪酸方面，脂肪酸的磨损较低，证明了酸的吸附能力增强。在DLC表面的吸附也被认为不仅是由于钝化键的形成（在酸和乙醇的情况下是酯的形成），而且还归因于从自由离子和电子产生促进有利乳化化学化学化学化学化学化学的分子植物的发展过程[6]。
Metal Nitride Coatings
由于其高硬度，低摩擦因子，对不同钢的优异粘附以及优质的热和化学稳定性，因此基于氮化物的硬涂层在钢上的应用正在增加。
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图片来源：photostock10/shutterstock.com
The thermal stability of single-layer coatings of TiN and MoN is not very high. At temperatures of 550–600°C, these coatings begin to oxidize, and consequently theirhardness is severely decreased [7, 8]. Therefore, multilayer nanostructured composites of metal nitrides showing improved physical, chemical, and tribological properties are being used for a range of applications. Such metal nitride multilayer nanocomposite materials were recently examined in Poland [7] using a universal mechanical testing jig for a ball-on-plate sliding mode. The study showed that the wear, friction, and load-carrying properties of multi-layered composites of TiN and MoN varied with their grain size.
It was concluded that decreasing monolayer thickness resulted in an increased hardness and smaller grain structure. An additional study on the effect of nano-layer thickness [8] revealed that nanostructured multilayer coatings, obtained by ARC/PVD methods, with layer thickness between 10 and 20 nm produced a friction coefficient in the range of 0.09 to 0.12. A 2015 study [9] reported that the use of cathode-arc evaporation (vacuum-arc method) for producing TiN/MoN alternating layers with superior tribological and physico-mechanical properties. The elemental and phase compositions, tribological properties, hardness and elastic modulus of such coatings show promises for their use as protective coatings for cutting tools, turbine blades, walls of chemical and nuclear reactors [9]. The deposition methods were followed by an annealing process that reduced the grain size of the coatings to impart such superior tribological and mechanical properties.
Universal Mechanical Testing
Mechanical testers are the key means of acquiring good data about the mechanical and tribological properties of both DLC coatings and nanocomposites. Development of stronger, harder, low friction, and inert materials leads to the development of technology that provides lighter, stronger, and less expensive tools, construction materials and consumer products.布鲁克的UMT Tribolab（图1）是一种最先进的通用机械测试仪，可以提供全范围的摩擦学和机械测试[10]来评估此类涂层。UMT Tribolab测试平台提供：
- Easy transformation from rotary to reciprocating motion
- 亚牛顿到牛顿牛顿力量测量
- 从周围到1000°C的温度进行环境测试
- A motor that accommodates the full range of speeds and torques
- 四个可互换的机械驱动器
- Wide selection of configurations including rotary, reciprocating, block-on-ring, linear tribology and scratch-test
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图1。布鲁克的UMT Tribolab
References
- S. Veprek and M. J.G. Veprek-Heijman, Industrial applications of super hard nanocomposite coatings, Surface & Coatings Technology 202 (2008) 5063–5073
- A. Erdemir and C. Donnet, Tribology of diamond-like carbon films: recent progress and future prospects, J. Phys. D: Appl. Phys. 39 (2006) R311–R327
- M. Kalin and R. Simiˇ Atomic force microscopy and tribology study of the adsorption of alcohols on diamond-like carbon coatings and steel, Applied Surface Science 271 (2013) 317– 328
- S. Stupp，《材料研究年度评论》，第31卷，年度亚博网站下载评论，2001年9月1日，科学，P2亚博老虎机网登录
- Erdemir A和Donnet C 2000 Modern Tribology手册，Ed B Bhushan（Boca Raton，FL：CRC出版社）pp 871–908
- R.Simič和M. Kalin，《 AFM研究的氢化DLC涂料的酒精和脂肪酸吸附的比较》，《机械工程杂志》 59（2013）12，707-718
- A Pogrebnjak et al, Structure and properties of multilayer nanostructured coatings TiN/MoN depend on deposition conditions, Acta Physica Polonica A, 2014, vol 125, no6, p1280-1283
- B. O. Postolnyi和A Pogrebnjak等人，纳米层厚度对多层锡/莫尼涂层的结构和特性的影响；2014年MAR，第1卷40，第3期，P215
- O. V. Bondar B. A. Postol’nyi。M. Beresnev，《锡，单层和锡/蒙蒙多层涂料》的构图，结构和三重技术特性，2015年1月，超级材料杂志亚博网站下载
- 布鲁克 - 摩擦学和机械测试人员
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