Dorgham Abdel, Parsaeian Pourya, Neville Anne, Ignatyev Konstantin, Mosselmans Fred, Masuko Masabumi, Morina Ardian
Institute of Functional Surfaces, School of Mechanical Engineering, University of Leeds Leeds LS2 9JT UK
Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0DE UK.
RSC Adv. 2018 Oct 4;8(59):34168-34181. doi: 10.1039/c8ra04753g. eCollection 2018 Sep 28.
One of the major obstacles in replacing the widely used zinc dialkyldithiophosphate (ZDDP) antiwear additive with a more environmentally friendly one is the difficulty of time-resolving the surface species resulting from its decomposition mechanism under high contact pressure and temperature. To tackle this issue, a newly developed miniature pin-on-disc tribotester was coupled with synchrotron X-ray absorption spectroscopy (XAS) to perform tribological tests while examining the composition of the formed triboreactive films. The results showed that in the case of bare steel surfaces the initial decomposition products are mainly zinc sulfate species, which with further shearing and heating are reduced to zinc sulfide mixed with metal oxides. The mixed base layer seems to enhance the tenacity of the subsequently formed zinc phosphate layers composing the main bulk of the protective triboreactive film. This base layer was not observed in the case of coated substrates with hydrogenated diamond-like carbon (a-C:H DLC) coating, which results in the formation of less durable films of small volume barely covering the contacting surfaces and readily removed by shear. Comprehensive decomposition pathways and kinetics for the ZDDP triboreactive films are proposed, which enable the control and modification of the ZDDP triboreactive films.
用更环保的添加剂替代广泛使用的二烷基二硫代磷酸锌（ZDDP）抗磨添加剂的主要障碍之一是，难以实时解析在高接触压力和温度下其分解机制所产生的表面物种。为了解决这个问题，一种新开发的微型销盘摩擦磨损试验机与同步加速器X射线吸收光谱（XAS）联用，以便在进行摩擦学测试的同时检测所形成的摩擦反应膜的成分。结果表明，在裸钢表面的情况下，初始分解产物主要是硫酸锌物种，随着进一步的剪切和加热，它们会还原为与金属氧化物混合的硫化锌。混合底层似乎增强了随后形成的构成保护性摩擦反应膜主要部分的磷酸锌层的韧性。在具有类金刚石碳（a-C:H DLC）涂层的涂层基材的情况下未观察到该底层，这导致形成的耐久性较差的薄膜体积小，几乎无法覆盖接触表面，并且容易被剪切去除。提出了ZDDP摩擦反应膜的综合分解途径和动力学，这使得能够对ZDDP摩擦反应膜进行控制和改性。
