A Novel Tool for Mechanistic Investigation of Boundary Lubrication: Stable Isotopic Tracers

摘要: 1.1 Surface analyses of tribological surfaces It is well understood that lubrication modes can be classified into three categories. Under hydrodynamic conditions, two rubbing are ideally separated by liquid film derived from lubricating oil. Therefore, the surface chemistry parts less importance. When operational conditions become severe, for example, under increased load, come in contact. This defined as boundary condition. these properties solid important. There an intermediate mode between and lubrication; namely mixed lubrication. Direct interaction may occasionally take place conditions. Tribo-chemistry controls performance [1]. Challenges to understanding rubbed tribologists using instrumental started early 1960s. Tribo-active elements such phosphorus sulfur were found electron-probe microanalysis (EPMA) lubricated with mineral oil containing additives [2]. These reports clearly support tribo-chemical reaction anti-wear extreme pressure (AW/EP). In 1970s, Auger electron spectroscopy (AES) was introduced a more sensitive tool tribology [3]. EPMA AES frequently applied tribo-chemistry useful tools. However, elemental identify only exist on surfaces. FeS, FeS2, FeSO4 analyzed, detected sample but could not chemical states found. X-ray photoelectron (XPS) provides different shifts iron sulfide (FeS) sulfate (FeSO4) S 2p spectra [4]. absorption near edge structure (XANES) identifies monosulfide disulfide (FeS2) [5]. mainly detect inorganic compounds. Although carbon detectable, resolution tools always sufficient identifying organic compounds detail. SIMS has been another analysis [6]. Contrary AES, EPMA, XANES, XPS, does provide any information regarding directly [7]. molecular weight substances On other hand, it detects all ionized primary ion. Both analyzed SIMS.