On the possible role of triboplasma in friction and wear of diamond-like carbon films in hydrogen-containing environments
On the possible role of triboplasma in friction and wear of diamond-like carbon films in hydrogen-containing environments
复制标题
DOI：
10.1088/0022-3727/42/7/075307
复制
发表时间：
2009-04-07
影响因子：
3.4
通讯作者：
Nakayama, K.
中科院分区：
文献类型：
--
作者：
Matta, C.;Eryilmaz, O. L.;Nakayama, K.
当在惰性和/或高真空环境中测试时，无氢类金刚石碳（DLC）膜（无定形（a-C）和四面体无定形碳（ta-C）两者）遭受高摩擦和严重磨损损失。然而，它们在测试环境中存在氢气、水蒸气和酒精分子的情况下提供异常的超低摩擦和磨损系数。在本文中，我们使用这样的薄膜在一个系统的研究，以进一步证实，氢确实在其摩擦和磨损行为中起着重要的作用。为了研究氢的影响，我们在含氢的试验室中进行了滑动试验，并使用飞行时间二次离子质谱仪分析了滑动接触表面的化学性质。显然，在含氢室中的摩擦学测试之后，碳膜的滑动接触区域变得非常富含氢。在试图了解所涉及的基本摩擦化学机制，我们进行了额外的测试，这些DLC膜使用高度仪表化的摩擦计，使我们的可视化的摩擦等离子体产生在或附近的滑动表面。在该测试系统中，我们证实了DLC膜的接触区域内的摩擦等离子体的形成，如特征UV辐射所证明的。基于这些观察结果，我们认为，这些DLC膜的接触区域内的摩擦等离子体的形成可能引发了其滑动表面上的氢原子和碳原子之间的独特摩擦化学反应，从而在含氢环境中的测试期间导致非常低的摩擦和磨损。
Hydrogen-free diamond-like carbon (DLC) films (both amorphous (a-C) and tetrahedral amorphous carbon (ta-C)) suffer high friction and severe wear losses when tested in inert and/or high vacuum environments. However, they provide anomalous superlow friction and wear coefficients in the presence of hydrogen gas, water vapour and alcohol molecules in the test environment. In this paper, we used such films in a systematic study to further confirm that hydrogen indeed plays an important role in their friction and wear behaviours. To study the effect of hydrogen, we conducted sliding tests in a hydrogen-containing test chamber and analysed the chemistry of their sliding contact surfaces using a time-of-flight secondary ion mass spectrometer. Clearly, the sliding contact regions of the carbon films became very rich in hydrogen after tribological tests in the hydrogen-containing chamber. In an attempt to understand the fundamental tribochemical mechanisms involved, we performed additional tests on these DLC films using a highly instrumented tribometer that permitted us the visualization of triboplasmas generating at or in the vicinity of the sliding surfaces. In this test system, we confirmed the formation of a triboplasma inside the contact area of the DLC films as evidenced by the characteristic UV radiation. Based on these observations, we believe that the formation of such triboplasmas within the contact zones of these DLC films may have triggered unique tribochemical reactions between hydrogen and carbon atoms on their sliding surfaces and thus resulted in very low friction and wear during tests in hydrogen-containing environments.