摘要:

AbstractZinc dithiophosphates (ZnDTPs) have been used extensively as anti‐wear agents for over 30 years. The mechanism of action of these remarkable materials is not fully understood. In particular, the molecular composition of the antiwear film produced by the ZnDTPs remains an area requiring investigation.In this paper, the molecular composition of adsorbed ZnDTPs on aluminium oxide (Al2O3) surfaces has been studied using Inelastic Electron Tunnelling Spectroscopy (IETS), a highly sensitive molecular spectroscopy specifically applicable to surface species at low coverages. As such, it complements other surface science techniques for determining surface compositions. A vibrational spectroscopy, IETS utilises the literature on group characteristic frequencies available from the very extensive correlations developed for infrared and Raman spectra. Thus, functional groups may be identified that are formed by the reaction of a lubricating oil additive with a metal surface covered by a native oxide.Using IETS, we show that ZnDTP aryl esters are dissociatively chemisorbed, and do not appear to form P=S groups bonded to the surface. By contrast, primary and secondary ZnDTPs retain the phosphate ester groups and bond to the surface by the P=S bond to different degrees. These spectral differences are qualitatively correlated with the observed antiwear performance of these material

ISSN:1354-4063    

DOI:10.1002/tt.3020030202

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDetailed knowledge about static friction materials is required for the accurate calculation of the braking torque needed to hold a load at rest. This is particularly important for brakes in cranes, elevators, hoists and mining winding machines, which must meet specifications such as the definite value of the static safe braking factor. The study of static friction is also a useful supplement to the dynamic testing of brake friction materials. In such a study, precise control of the temperature on the surfaces is possible, as well as surface roughness, and existence of the third‐body can be accurately identified. It is an important fact that the coefficient of static friction, μs, is not an invariant, and it cannot be adequately represented in many engineering applications as a single number. The study of static friction dependence upon factors such as stationary contact time, rate of tangential loading, and surface temperature, contributes to a better understanding of friction phenomena.In this paper, a test apparatus is presented, and a series of experiments is described. The experiments reveal the static friction characteristics of some brake friction materia

ISSN:1354-4063    

DOI:10.1002/tt.3020030203

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA study was conducted to determine the effect of amplitude and test time on surface damage in metal‐to‐metal contact under lubricated conditions. The test set up consisted of a ball loaded against a flat disc, with an external drive imparting a linear oscillatory motion to the ball on the flat. The materials were steel AISI 52100/AISI 52100, and the lubricant was ISO VG 220. Damage characteristics were defined for amplitudes in the range of 5 to 50 microns and for test times of 10 to 360

ISSN:1354-4063    

DOI:10.1002/tt.3020030204

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA transfer film plays a very important role in the sliding wear process. This paper discusses a factor, ‚adhesive energy’︁, which affects the formation of transfer film on the ceramic's surface during sliding friction of ceramics against metals. On the basis of both a theoretical evaluation of adhesive energies, and experimental results, it can be concluded that the adhesive energy between ceramics and metals is the controlling factor in the formation of transfer film on the ceramic surface. A new semi‐quantitative method to determine the relative thickness of transfer film on ceramic surface with EDAX is di

ISSN:1354-4063    

DOI:10.1002/tt.3020030205

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPlasma sprayed ceramic coatings are used in a number of industries in which surface modification of components to compare tribological properties is important: so hence, are evaluations of their tribological properties. This paper presents a study on the wear behaviour of three ceramic coatings — Al2O3, TiO2and Al2O3‐TiO2combination — in the load and speed ranges of 5 to 50 N, and 0.3 to 10 m/s, respectively, on which few data are available in the literature. The tests were carried out using a standard dry sand rubber wheel abrasion test and a pin‐on‐disc machine under dry sliding conditions. It was found that a stick‐slip effect seems to occur at low sliding speeds, and transition takes place at a sliding speed of around 4 m/s. Of the three ceramic coatings, TiO2was found to be the most wear resistant, with the least friction coefficient, although it is less hard than the Al2O3coatings. Scanning electron microscopy of the surface shows evidence of wear mechanisms such as plastic deformation, transfer‐film formation, micro cracks, and grain pull‐out

ISSN:1354-4063    

DOI:10.1002/tt.3020030206

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper proposes an approach to the problems of simulation and description of tribosystems, based on an investigation of various fundamental aspects of tribosystem operation. A complex of parameters to be measured in testing, and characteristics analysed after the tests, are selected, using the authors' experience in tribotesting. Methods of processing experimental data and their interpretation are discussed. The approach described here has been successfully used for solution of various practical problems.

ISSN:1354-4063    

DOI:10.1002/tt.3020030207

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020030208

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020030209

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020030201

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY