摘要:

AbstractComputer simulation of the inhibited oxidation of model hydrocarbon systems representing turbine oils of different composition, hexadecane/tetralin mixtures containing di‐tert‐butyl pcresol (DBPC), has been achieved using the kinetic and mechanistic information obtained from fundamental hydrocarbon autoxidation and inhibition studies. The oxidation life, the time to complete consumption of DBPC and its reactive intermediates, was calculated using previously reported and newly measured absolute rate constants for reaction involved. The results of this calculation of oxidation life were in good agreement with values experimentally determined. The oxidation life has been found to decrease with increasing amount of tetralin in the mixtures. This can be explained by the increased rate of consumption of antioxidants, caused by an increase in the rate of free radical formation, via the direct reaction of hydrocarbons with oxygen, and via the homolytic decomposition of hydroperoxides. The observed decrease in oxidation life, however, is not significant, despite the fact that the addition of tetralin considerably increases the rate of free‐radical formation. The relatively low sensitivity of oxidation life to the rate of free‐radical formation caused by the addition of an easily oxidisable substrate can be attributed to the occurrence of a direct oxidation of antioxidants. That is, kinetic analysis for the consumption of antioxidants disclosed that antioxidant consumption mostly occurred not through the inhibition of oxidation, but through direct oxidation. The direct oxidation of antioxidants obeys the rate equation ‐d[AH]/dt = k6[AH]1.0[O2]1.5where k6can be calculated, at various temperatures, from Arrhenius parameters obtained in this study (log (A/M−1s−1) = 9.6 and Ea = 22

ISSN:0954-0075    

DOI:10.1002/ls.3010070102

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA strong synergism between overbased sulphonate (OBS) and zinc dialkyldithiophosphate (ZDDP) in a proven diesel engine oil formulation has been reported in an earlier communication.1In continuation of these studies, the effect of different types of dispersant, of varying nitrogen content, and an antioxidant, on a synergistic combination of OBS‐ZDDP has been investigated. Both detergency and dispersancy of the optimised formulation were improved with high nitrogen‐content dispersants, which also increased strongly the wear tendencies. The antioxidant, though it improved detergency, did not show any positive effect on antiwear performance. Detailed IR and31p‐NMR spectroscopic analyses on interactive additive pairs, namely, ZDDP‐PIBS and ZDDP‐antioxidant, indicated the formation of association complexes and hydrogen bonding res

ISSN:0954-0075    

DOI:10.1002/ls.3010070103

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper reports on an anti‐adhesive wear lubricant (NL2) used in deep drawing, containing as additives B, N compounds and zinc (cyclic) polymethylenedithiophosphate. It covers the synthesis of these additives, their properties, and the friction and wear mechanism of NL2 in the deep‐drawing process. These are studied by means of a strip bending drawing tester, a four‐ball tester, and IR, SEM, and EDAX analysis. The results show that the new additive gives good adhesive wear protection in deep dr

ISSN:0954-0075    

DOI:10.1002/ls.3010070104

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA sulphur‐containing organic borate (BS‐2) was prepared. Its friction and wear properties when added to n‐tetradecane, and the effect on wear of addition of dodecyl amine to the synthesised S‐containing borate oil, were measured using a Timken test machine. The results were compared with those of tridodecyl borate, and a combination of tridodecyl borate and sulphurised cotton seed oil. X‐ray Photoelectron Spectroscopy (XPS) was used to examine the rubbed surfaces of the test blocks, while Scanning Electron Microscopy (SEM), Energy Dispersion Analysis of X‐ray (EDAX) and X‐ray Diffraction (XRD) were used to study the wear debris.It is found that S‐containing organic borate exhibits a poorer antiwear property than tridodecyl borate but, with the addition of dodecyl amine to the S‐containing borate, its antiwear property can be improved. XPS analyses indicate that sulphur on the rubbed surfaces exists in the forms of organic sulphide and FeSO4, and the addition of amine reduces the adsorption and reaction of sulphur to the rubbing surfaces. SEM analyses revealed that the wear debris was in powder form, and the EDAX and XRD analyses indicated that iron sulphide, iron oxide and elemental iron were contained in the wear debris. A corrosive wear mechanism of steel test blocks lubricated by S‐containing organic

ISSN:0954-0075    

DOI:10.1002/ls.3010070105

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe antiwear and EP properties of certain p‐chlorophenyl groups containing nitrogen and sulphur open‐chain and cyclic compounds, in paraffin oil, were evaluated in a four‐ball test. The performance of the additives were compared with a commercially available sulphur‐phosphorus reference additive. All the additives, in general, exhibited good EP activity at different loads as compared to paraffin oil and the reference additive. However, the cyclic additives, e.g., 2‐phenyl‐3‐phenylimino‐5‐p‐Cl‐phenylamino‐1,2,4‐thiadiazolidine, and 2‐amino‐5‐p‐Cl‐phenylamino‐1,3,4‐thiadiazole, were found to possess good antiwear and EP properties in comparison to the plain paraffin oil, reference additive, and open chain additives. The wear surface tribochemistry and topography were studied using Scanning Auger Electron Spectroscopy (AES) and Scanning Electron Microscopy (SEM) techniques, respectively.A comparative EP activity evaluation of 1‐p‐Cl‐phenyl‐2,5‐dithiohydrazodicarbonamide and 3‐p‐Cl‐phenylimino‐5‐(N‐methylphenyl)amino‐1,2,4‐dithiazoline on steel bearing balls of different composition was undertaken to assess the suitability of replacing chromium alloy steel balls with cheaper carbon steel balls. The additive, 3‐p‐Cl‐phenylimino‐5‐(N‐methylphenyl)amino‐1,2,4‐dithiazoline exhibited its effectiveness on the alloy steel as well as low carbon steel bearing balls.A plausible explanation for the enhanced activity of additives is suggested and eff

ISSN:0954-0075    

DOI:10.1002/ls.3010070106

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe antiwear (AW) and extreme pressure (EP) properties of chlorine, sulphur, phosphorus‐containing organic compounds and zinc dialkyldithiophosphate (ZDDP) oil additives are affected greatly by their reactive ability to the metal surface, as well as by the chemical composition, chemical state, physical and mechanical properties of the protective films formed. Over four decades, research has taken place on boundary lubrication, and a much better understanding of the AW and EP action mechanism of one additive by itself in base oil has been obtained, and much more knowledge on the relationship between wear and decomposition of additives, adsorption and reaction of the additive or its decomposed products with metal, has been gained. A series of analytical methods and a great number of modern surface analytical tools have been set up and used for research in this area. The problems and some suggestions for the future study on boundary lubrication of oil additive are propose

ISSN:0954-0075    

DOI:10.1002/ls.3010070107

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractZDDP reacts with oil‐soluble copper salts to form complex compounds and these compounds can substantially surpass the initial additive in the effectiveness of antiwear and antioxidant action. Application of AES allows us to establish the influence of ZDDP and complex compounds formed by it on the structural state of the friction surfaces. The specific nature of action of these complex compounds lies in minimisation of the oxidation processes in the surface microvolumes of the lubricating medium, the consequence of which is the localisation of tribo‐chemical processes of secondary structure‐film formation in the thinner layers. On the whole, the results obtained offer evidence of the existence of certain interrelations and generality of the processes producing antiwear and antioxidant action by zinc dithiophosphate additives in lubricating l

ISSN:0954-0075    

DOI:10.1002/ls.3010070108

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010070101

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY