摘要:

AbstractAshless dispersants of the type of alkenyl‐succinic anhydride derivatives were prepared. The resistance of these compounds to oxidation and thermal decomposition was investigated by thermoanalytical methods. Results were compared to those obtained in a panel coking test of these additives at 300°C in a multifunctional package. It was found that data obtained by DSC could be used for rating the stability of polyisobutenyl‐succinimides against thermo‐oxi

ISSN:0954-0075    

DOI:10.1002/ls.3010040202

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe antiwear (AW) and extreme‐pressure (EP) properties of some metallic dialkyl‐ and diaryldithiophosphates (MDTP), including zinc, have been studied in different metal/metal contact conditions: four‐ball and FZG rigs.It was noted that with pure dialkyldithiophosphates of different divalent metals (Zn, Cd, Cu, Pb, Ni, Co), prepared from the same alcohol, four‐ball, EP results, expressed in terms of load‐wear index, show that the highest performances are obtained with ZnDTP, but, statistically, the higher the ionic radius of the metal, the better the performance, while EP results, expressed in terms of weld load, do not show any difference between the MDTPs. Four‐ball AW results, expressed in terms of wear scar, show that the highest performances are obtained with ZnDTPs; beyond a certain value these performances with Zn and Pb are almost independent of the concentration. For the other metallic DTPs, there is a very close relationship between performance and concentration.On the FZG gear rig, EP‐AW results, expressed in terms of failure load stage and specific wear, show that statistically, the higher the ionic radius of the metal, the better the performance. With ZnDTP four‐ball, EP results, expressed in terms of load wear index, do not depend on the chemical structure of the alcohol used for synthesised ZnDTP, but, if results are expressed in terms of weld load, better performances are obtained with ZnDTP synthesised from secondary alcohols. AW results show that the effectiveness of ZnDTP from secondary alcohols is slightly higher when the alcohols used contain less than six carbon atoms. Beyond six carbon atoms in primary or secondary alcohol molecules, performances decrease. FZG, EP‐AW results show that performance does not depend on the primary or secondary nature of the alcohols used, and that th

ISSN:0954-0075    

DOI:10.1002/ls.3010040203

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThin‐layer transducers, which are mainly used for the measurement of the EHD contact parameters, have to be attached to an isolating layer separating it from the steel roller. The isolating layer, made of SiOxor Al2O3,disturbs heat flow in relation to the real contact. This paper presents a solution for the system of two heat conduction equations for a two‐layer body: SiOx‐steel. The boundary conditions reflect the real situation during the measurements carried out by means of these transducers. The solution was obtained for an assumed temperature distribution of the isolating layer surface. Computation results for two different temperature distributions of the surface and for various values of the SiOx‐layer thickness are also pr

ISSN:0954-0075    

DOI:10.1002/ls.3010040204

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractChemiluminescence is reviewed as a method of characterising different behaviour of lubricating oils. This includes mineral oils containing additives such as zinc dialkyl‐dithiophosphates, sulphonates, succinamides. alkylphenols and polymers. Using a chemiluminescence apparatus and manometric apparatus, various lubricant oil fractions blended with additives were examined. The basic emitters of chemiluminescence are excited carbonyl compounds, and results are presented showing the measurement of chemiluminescence at elevated temperature

ISSN:0954-0075    

DOI:10.1002/ls.3010040205

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractExtending automotive engine drain intervals requires a good knowledge of the antiwear aspect of lubricant performance, which is often closely linked to the oxidative degradation of the oils. In this paper, we report the physicochemical analyses and tribological tests carried out on several oils oxidised by laboratory oxidation tests at different stages. An interesting correlation was found between the antiwear efficiency and some characteristics of the eletrochemical impedance spectra of such oxidised lubricants. A promising way of understanding the mechanisms of wear mitigation by aged engine oils is proposed.

ISSN:0954-0075    

DOI:10.1002/ls.3010040206

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010040201

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY