摘要:

AbstractThe antiwear and extreme‐pressure properties of six different types of additive (molybdenum dialkyldithiophosphate, dibenzyl disulphide, molybdenum dialkyldithiocarbamate, zinc dialkyldithiophosphate, chlorinated paraffin wax, and triaryl phosphate) were evaluated by standard four‐ball friction and wear tests. This was followed by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and X‐ray photoelectron imaging (XPI) analyses of the worn surfaces to determine the structure of the boundary lubrication film and the mechanism of the tribochemical reaction occurring during the friction process. The presence of the additives in the base oil significantly increased the weld load and drastically reduced the wear‐scar diameter, suggesting antiwear and extreme‐pressure properties of the additives. The enhanced antiwear and loadcarrying capacity of the additive‐containing oils was attributed to the formation of a complex boundary lubrication film formed between the surfaces during the friction process as a result of the tribochemical reaction. The antiwear and extreme‐pressure properties of the additives were explained based on the XPS data. The studies indicated that the lubricating properties of the additives depend on their chemical nature and reactivity with

ISSN:1354-4063    

DOI:10.1002/tt.3020090402

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractIn this paper, a recently developed light‐section technique is demonstrated as a viable technique for the measurement of the topography of moving surfaces. The sensitivity and precision of this technique are statically and dynamically evaluated for samples of different roughness. It is shown that an optical system using the light‐section method is not only precise but also immune to the effects of perpendicular and lateral motion of the surface. It is therefore well suited to on‐line monitoring of the change of profile of moving surfaces. The technique, with its ability to measure the topography of moving surfaces without contact, provides a most effective tool for the study of wear and lubrication mechanisms under partial elastohydrodynamic lubric

ISSN:1354-4063    

DOI:10.1002/tt.3020090403

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractThe work reported here used infrared (IR), multinuclear nuclear magnetic resonance (NMR), and chromatographic techniques to identify and characterise a commercial sulphur‐ and nitrogen‐containing ashless multifunctional additive. The proper assignment of signals in the1H/13C NMR and IR spectra of the sample has facilitated the identification of different types of sulphur‐ and nitrogen‐containing components. The methodology involves investigation by NMR and IR spectroscopies, thin‐layer chromatography (TLC) and high‐performance liquid chromatogaphy (HPLC) techniques to elucidate the types of components present. This requires the generation of NMR and IR spectral data for standard compounds of alkyl sulphides with different sulphur content and alkyl chain, and nitrogen and sulphur components such as thiadiazole, imidazoline, triazole, etc., and spectral comparison with the spectra of the unknown sample. Further, these components have been separated by silica/alumina column chromatographic and preparative TLC techniques and subsequently analysed for their exact chemical structure by spectroscopic techniques. The combined spectroscopic and chromatographic analyses have yielded the presence of four types of components: di‐t‐octyl polysulphide, di‐t‐octyl thiadiazole, a component containing amine ether functionality, and alkyl amine salts of mono/dial

ISSN:1354-4063    

DOI:10.1002/tt.3020090404

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractNanoscopic metal contact in the context used in this paper means atomic force microscope (AFM) tips in contact with cleaned, flat, smooth surfaces in ultrahigh vacuum. Such idealised contact conditions are of more and more relevance for technical friction systems despite the fact that for the latter the loads and the velocities are usually higher, the materials used are impure (e. g. alloys) and contaminants or lubricants are present between the sliding surfaces. Sliding contacts in micro‐system technology, which is unequivocally a key technology of the future, will presumably be compared with such idealised conditions. Another important reason for the investigation of nanoscopic contacts is the strong interest in the understanding of the elementary processes and mechanisms causing friction. The investigation of friction systems with a reduced number of influencing parameters offers a chance to gain insight into elementary processes and to compare the results with theoretical models based on physical principles, such as molecular dynamics simulatio

ISSN:1354-4063    

DOI:10.1002/tt.3020090405

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractThe friction behaviour of wet clutches for automatic transmission applications strongly influences the dynamic behaviour of the entire machine or vehicle, including the transmission. The wear, and also the friction curve, determines the life of the clutch.In this research, both SAE II and pin‐on‐disc tests have been used to investigate the wear and friction characteristics of paper friction material. A comparison is made of the friction coefficients and the wear rates obtained on both test rigs. Although the pin‐on‐disc tests failed to reproduce correctly the wear rates of the SAE II tests, they can be used for a qualitative analysis of the influence of material parameters and operating conditions on both friction coefficients and wea

ISSN:1354-4063    

DOI:10.1002/tt.3020090406

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020090407

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020090408

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020090401

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY