Boundary lubricating films: formation and lubrication mechanism
Boundary lubricating films: formation and lubrication mechanism
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DOI：
10.1016/j.triboint.2004.08.021
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发表时间：
2005-03-01
影响因子：
6.2
通讯作者：
Gates, RS
中科院分区：
文献类型：
--
作者：
Hsu, SM;Gates, RS
边界润滑膜是发动机部件有效润滑的关键。由于缺乏对基础油和抗磨添加剂的分子结构如何共同作用的理解，它们的形成机理尚未完全了解。本文研究了基础油的分子结构及其对高分子量有机金属化合物生成反应速率的影响。用液相色谱法将三种基础油分离成饱和分、芳烃分和极性分子，并对这些馏分进行了微氧化试验。有机化合物检测耦合凝胶渗透色谱-原子吸收光谱法。极性分子的有机金属化合物生成速率最高，饱和度最低。对磨损样品和发动机部件的薄膜进行分析，证实了类似的有机金属化合物的存在。当与来自抗磨添加剂如二烷基二硫代磷酸锌（ZDDP）的反应膜组合时，软有机金属化合物提供容易剪切的牺牲层，并且无机磷酸盐玻璃状结构提供承载能力。所得的边界膜更坚固且耐用。这一认识为未来边界膜的设计提供了指导。(C)2004爱思唯尔有限公司保留所有权利。
Boundary lubricating films are critical in effective lubrication of engine components. Their formation mechanism is not fully understood due to the lack of understanding of how molecular structures of the base oils and the antiwear additives work together. This paper examines, the base oil molecular structures and their influence on the reaction rates leading to the formation of high molecular weight organometallic compounds. Three base oils have been separated into saturates, aromatics, and polar molecules by liquid column chromatography and these fractions are studied in a micro-oxidation test. Organometallic compounds were detected by a coupled gel permeation chromatograph-atomic absorption spectroscopy. Polar molecules show the highest organometallic compound formation rate while saturates the lowest. Analysis on films from worn samples and engine components confirmed the presence of similar organometallic compounds. When combined with reaction films from antiwear additive such as zinc dialkyl dithiophosphate (ZDDP), the soft organometallic compounds provide an easily shearable sacrificial layer and the inorganic phosphate glassy structure provides the load carrying capacity. The resultant boundary film is stronger and durable. This understanding provides a design guideline for future boundary films. (C) 2004 Elsevier Ltd. All rights reserved.