bluuebunny/crossref_metadata_2025_split huggingface dataset:
Additive‐additive and additive‐surface interactions in lubrication
Authors: Spikes H. A. 
Published: July 2006

AbstractCombinations of additives are often found to exhibit antagonistic or synergistic effects compared to the performance of the individual additives. This paper reviews the state of knowledge concerning such effects. Direct interactions, where two additives combine at a molecular level, are distinguished from complementary or exclusary effects where the individual contributions of separate additives enhance or reduce overall performance but with no direct interaction. Additive interactions take place in solution and at surfaces, and both are discussed.
Acceleration of wear of steel with fatty acid and oxygen under rolling with sliding partial EHD conditions
Authors: Masuko M. , Shiomi S. , Okabe H. 
Published: July 2006

AbstractQuantitative evaluation was used to study the effect of surface roughness on wear behaviour of steel under rolling with sliding partial EHD conditions, and to clarify the effect of an additive and operating environment. It was found that the wear behaviour under conditions of lubrication with mineral oil was governed by the oxidation of the surface, regardless of whether the lubricant was formulated was with or and without additive. It was also found that wear was accelerated by the addition of fatty acid in the presence of oxygen, whereas it was not affected for lubrication with additive‐free mineral oil. It is considered that the acceleration of wear by addition of fatty acid is closely related to the oxidation of the surface during friction.
Lubricated wear of PTFE and graphited PTFE
Authors: Sethuramiah A. , Awasthy K. L. , Prakash Braham , Mahapatra P. K. 
Published: July 2006

AbstractTribological behaviour of PTFE and graphited PTFE have been evaluated under lubricated conditions and compared with dry wear. The stress selected is in the range of 0.44 to 1.64 MPa, and the data generated are relevant to conformal contacts. Mineral oil lubrication can reduce wear of PTFE by one to two orders of magnitude. With graphited PTFE the lubricant effect is lower in comparison to that observed with PTFE. Specific wear rates are plotted on a histogram.
The relationship between chemical structure and effectiveness of some metallic dialkyl‐ and diaryl‐dithiophosphates in different lubricated mechanisms
Authors: Born M. , Hipeaux J. C. , Marchand P. , Parc G. 
Published: July 2006

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 the smaller the hy‐.
Influence of different friction conditions on the process of cold backward extrusion of steel
Authors: Plancak M. 
Published: July 2006

AbstractBackward extrusion of steel is a deformation process in which very high forces and tool pressures occur. Reduction of such high forces and tool pressures is possible by using an efficient lubricant. This paper describes an experimental investigation of the influence of different lubricants on the stress‐strain state within the workpiece volume as well as on the stressing of the die. Best results were obtained when a phosphate‐coated specimen was lubricated with MoS2.
Effect of consolidation in boundary lubrication
Authors: Georges J. M. , Mazuyer D. , Loubet J. L. , Tonck A. 
Published: July 2006

AbstractThis paper is concerned with the effects of the colloidal aspect in boundary lubrication. The newly developed method for surface forces measurement has clearly shown the consolidation effect during contact loading.The paper also shows that, in some cases, the friction coefficient varies with the compaction of wear particles in the contact. Friction experiments between a ball and flat (both sapphire) in which the contact is immersed in water, have been performed to understand the effect of compaction of worn material on friction. During friction, wear debris is piled up in the contact and shear behaviour depends on pressure and volume fraction of wear particles.
Soluble molybdenum compound and sulphur ep additive combinations: Synergistic and adverse effects on antifriction and antiwear characteristics
Authors: Sarin R. , Gupta A. K. , Sureshbabu A. V. , Martin V. , Misra A. K. , Bhatnagar A. K. 
Published: July 2006

AbstractAntifriction and antiwear performance of three soluble molybdenum (Mo) compounds (Mo dithiophosphate, Mo dithiocarbamate and Mo amine complex) and four sulphur‐containing EP additives (sulphurised isobutylene, dibenzyl disulphide, sulphurised fat and synthesised ethylene sulphur derivative) have been studied, alone and in combination, using an SRV test rig. The additive behaviour in combination has been found to be selective, and dependent on the chemistry and ratio of the additive components. Certain sulphur EP additives in combination with Mo compounds have exhibited a synergistic effect. The antifriction performance of additives, in general, has been found to be further enhanced at higher test temperatures. However, a reduction in antiwear property has been noticed.
Reliable model of lubricant‐related friction in internal combustion engines
Authors: Benchaita M. T. , Lockwood F. E. 
Published: July 2006

AbstractA linear model of lubricant‐related engine friction was developed. Based on lubrication fundamentals, the technique is comprised of three simple bench tests that respectively operate under thick fluid‐film hydrodynamic lubrication, elastohydrodynamic lubrication, and boundary lubrication. With adequate configuration and appropriate test conditions, these bench tests are seen to simulate major friction losses in a typical internal combustion engine.Lubricant characteristics obtained in the bench tests were combined using SAS linear regression and correlated to ASTM Five‐Car and Sequence VI engine tests. The linear model gave an excellent prediction of engine data. It further showed that hydrodynamic friction losses dominate lubricant‐related engine friction, followed by boundary friction losses, and elastohydrodynamic or mixed friction losses. This simple, reliable, and inexpensive technique can be used as a research tool to study friction characteristics of crankcase lubricants and to develop superior fuel‐efficient engine oils.Major findings from this study can be summarised as follows:

The linear model predicts that 5 to 6% fuel economy improvement over the industry high reference oil HR‐4 is achievable with today's motor oil technology
Hydrodynamic friction losses in both ‘thick' and ’thin' fluid‐film lubrication account for 63% of total friction losses caused by the engine oil while boundary friction losses amount to 37%.
Friction losses in the elastohydrodynamic (EHD) engine are significant, up to 22% of total friction losses. This, combined with the fact that EHD film thickness is the most significant parameter in the linear model, suggests that pressure effects (ie, high‐temperature/high‐shear/high‐pressure viscosity, pressure‐viscosity coefficients) are important.
Increasing fuel economy improvement is in general in the order: SAE 10W–40 < SAE 10W–30 < SAE 5W–30, providing that base stock and additive systems are unchanged.
Computer modeling of rheological properties of base oil compositions with selected additives
Authors: Kajdas Czeslaw , Warsaw Roman Kempinski 
Published: July 2006

AbstractAn analysis of the rheological properties of various oils and their formulations with selected rheological additives (Visconyl‐200 and ECA‐6911) was performed. Base oils (OS and OU) obtained on a large laboratory scale were the primary subject of the investigation. They were produced according to classical and modified base oil technologies. The modification introduced an additional process of mild oxidation of atmospheric residue before vacuum distillation. Other oils, such as aromatic and saturated hydrocarbons separated from the OS and OU oils, as well as oil fractions (1S–5S and 1U‐5U) obtained from the base oils by vacuum distillation, have also been investigated.Using the rheological properties determined for the distillate oil fractions formulated with the Visconyl and ECA additives, the empirical formulae describing the dependence of kinematic viscosity v50, c and v100, c and of the pour point of the compositions, on the basic physico‐chemical properties of the base oils, and on the type and concentration of additive, have been found. The theoretical viscosity index values of the oil compositions were also characterised indirectly by using the empirical formulae describing kinematic viscosities of the compositions at 50 and 100°C. The formulae obtained were successfully tested with several selected base oils.
The characterisation of synthetic sulphonate and phenate detergents by nuclear magnetic resonance and infrared spectroscopy
Authors: van de Ven A. M. C. , Johal P. S. , Jansen L. 
Published: July 2006

AbstractSulphonate and phenate detergents are used in many modern oil formulations. Overbased sulphonates form micelles, whereas in overbased phenates the excess metal carbonate is incorporated in the molecule as a carbonate chain. This is the cause of broad unresolved peaks in the NMR spectra of these detergents. Hydrolysis removes the excess metal carbonate and converts the sulphonates and phenates to sulphonic acids and phenols respectively. Especially in the 1H‐ and 13C‐NMR spectra, a substantial resolution enhancement is achieved after hydrolysis. These spectra reveal much more structural information. One of the features that can be calculated from the 13C‐NMR spectra is the mean alkyl chain length.In this study a number of commercially available sulphonate and phenate detergents have been investigated. For the sulphonates the alkyl chain length was found to range from 17–22 carbon atoms, and for the phenates the alkyl chain length proved to be approximately 9–12 carbon atoms. The phenate alkyl chains showed significantly more branching than those in the sulphonates.In the 1H‐NMR spectra, the position of the acidic proton signals is influenced by the measurement temperature, water concentration and solvent. The effect of these parameters was studied in detail.A combination of sample preparation techniques, such as dialysis, and hydrolysis and spectroscopic techniques, such as IR and NMR, can be used successfully to characterise detergents in terms of their molecular structure.
Friction characteristics of piston rings in a reciprocating engine
Authors: Hamatake T. , Kitahara T. , Wakuri Y. , Soejima M. 
Published: July 2006

AbstractThe performance of a reciprocating engine can be improved by reducing the friction between piston rings and cylinder liner, which significantly contributes to the mechanical friction losses of an engine.The friction force of a piston ring pack is calculated, based on hydrodynamic lubrication theory, for the piston rings. Calculations were carried out for three sets of conditions. Oil starvation is taken into consideration in the calculation of oil‐film behaviour for a ring pack. The friction characteristics of piston rings are evaluated using the frictional mean effective pressure.The friction force of a piston assembly is measured experimentally by an improved floating liner method. The effects of lubricant viscosity and engine speed on friction characteristics are investigated by both calculation and experiment.
Effect of molecular structure of organic borates on their friction and wear properties
Authors: Liu Weimin , Xue Qunji , Zhang Xushou , Wang Hanqing 
Published: July 2006

AbstractSix organic borates of different molecular chain length were synthesised, and the friction and wear properties of these borates as oil additives were evaluated using a Timken Tester. X‐ray photoelectron Spectroscopy (XPS) was used to study the surface composition and valence state of boron on the rubbed surfaces.It was found that the antiwear and friction reduction effects of the borates are significantly influenced by the molecular chain length. The longer the chain length, the lower the friction coefficient and wear, and the higher the failure load. XPS analyses of rubbed surfaces revealed that the binding energy of BIS increased after rubbing, but no pure B(OH)3 and B2O3 was generated. the load‐carrying capacity and the antiwear effect are probably related to the ratio of numbers of carbon atoms to numbers of boron atoms on the rubbed surfaces.
Importance of anionic reactive intermediates for lubricant component reactions with friction surfaces
Authors: Kajdas Czeslaw 
Published: July 2006

AbstractTo understand the chemical behaviour of lubricant components during boundary lubrication, a general concept of negative ionradical reactive intermediates formation for these components has been proposed. The concept is based upon the ionisation mechanism of these compounds caused by the action of electrons of law energy (1–4 eV). Electrons of such energy (exoelectrons) are spontaneously emitted from most fresh surfaces formed during friction. The principal thesis of the model is that lubricant components form anions which are then chemisorbed on the positively charged areas of rubbing surfaces.The formation of negative ions and their decomposition process are simulated by electron attachment mass spectrography. This type of mass spectrography uses electrons of an energy range similar to those of exoelectrons. The proposed model encompasses the following major stages: (a) low‐energy electron emission process and creation of positively charged spots, (b) action of emitted electrons with lubricant components (anion and radical formation), (c) reactions of anions with metal surfaces forming a film protecting the surface from wear, (d) cracking of chemical bonds producing other radicals. The model explains many lubrication phenomena of hydrocarbons, oxygen‐containing compounds, and many types of chemicals used as antiwear and extreme‐pressure additives.
Succinimide phosphoric acid esters as multipurpose additives
Authors: Naga H. H. Abou El , Mohamed M. M. , El Meneir M. F. 
Published: July 2006

AbstractSuccinimide phosphoric acid esters have been synthesised and evaluated as antioxidants and ashless dispersant additives for crankcase lubricating oils. The synthesis is based on reacting succinimides (as prepared by the reaction of polyisobutylene, maleic anhydride and tetraethylene pentamine) with phosphorus pentoxide in the presence of alcohols with different carbon numbers Results showed that the magnitude of the oils' oxidation stability, as well as their dispersive power, are both highly related to the chemical structure of the alcohol used.
Computer simulation of turbine oil oxidation. 2: Consumption of a hindered phenol antioxidant in laboratory oxidation tests and in service
Authors: Igarashi Jinichi , Yoshida Toshio 
Published: July 2006

AbstractThe computer simulation study of consumption of di‐tert‐butyl p‐cresol (DBPC) was extended to the oxidation of hexadecane/tetralin model oils under conditions of laboratory oxidation tests and in service. The oxidation lives of the model oils in the ALCOA oxidation test and the ASTM D2272 rotary bomb and D943 turbine oil oxidation tests were successfully predicted from the simulation study. The oxidation behaviour of the model oils is compared to that of a turbine oil used in actual service units. The model oil having 6 mass % of tetralin showed almost identical oxidation behaviour to the turbine oil when the same amount of DBPC was added (0.6 mass %). The calculation shows that the direct oxidation of antioxidants is the main process of antioxidant consumption in the laboratory oxidation tests as well as in the model oxidation system without metal catalysts. In most of the service units which operated at moderate conditions the calculation shows that the direct oxidation of antioxidants is also the main, process. As a consequence, the rate of antioxidant consumption does not depend much on the tetralin content in the model oils. The oxidation behaviour of the model oils in the service units which operate under severe conditions, such as in the high temperature regions of turbines, is calculated by setting a flow reactor model. The results of this calculation show in this case that the turbine oil degradation occurs mostly in the high temperature regions and that the rate of antioxidant consumption increases with an increased amount of tetralin in the model oils. This strong dependence on base oil composition can be attributed to the increased importance of antioxidant consumption through the inhibition of oxidation.
Laboratory screening tests for low sulphur diesel fuel lubricity
Authors: Cooper D. 
Published: July 2006

AbstractSince the beginning of October 1993, environmental legislation in the USA has required the sulphur content of diesel fuel to be reduced to less than 0.05 wt.% for road vehicles. Pressure for such reductions to be adopted in other markets is growing: notably, sulphur levels as low as 10 ppm are being encouraged in Sweden by the use of tax incentives. However, it is suspected that fuel pumps suffer from lubrication problems with the use of low sulphur diesel (LSD). Additive treatment of fuels and fuel blending is thought to mitigate such problems but there is a need for an industrial method of screening candidate fuel treatments prior to expensive service or rig trials.This paper outlines a test procedure based on the Plint TE‐77 reciprocating test rig. Initial investigations have enabled fuels of known pump performance to be ranked correctly through an assessment of scuffing wear. In this test, scuffing is evaluated by surface profilometry of the flat specimen and the mechanism is verified by the detection of ‘white’ etching layers on surfaces. The test also allows the separate evaluation of mild wear by measurement of the width of the scar generated on the roller by the line contact configuration.
A study of alkylthiomethylbenzotriazoles as multifunctional lubricating oil additives
Authors: Ren Tianhui , Wan Yong , Xue Qunji , Wang Hanqing 
Published: July 2006

AbstractThree new oil‐soluble alkylthiomethylbenzotriazoles were synthesised with the reaction of 1‐chloromethylbenzotriazole and sodium alkyl mercaptan in iso‐propanol at room temperature for 12 h. Their load‐carrying capacity and friction and wear properties when added to liquid paraffin were then evaluated using a Seta‐shell four‐ball machine. Their thermal stability in static air was examined by DSC analysis, and their friction reduction and antiwear mechanisms were investigated using XPS and AES analysis.
Functional mechanism of formation of friction polymer with dihydroxydocosanoic acid
Authors: Hu Zhimeng , Tao Dehua , Wang Ru‐Lin 
Published: July 2006

AbstractThe results of wear tests with a four‐ball machine showed that dihydroxydocosanoic acid has good antiwear properties, comparatively approaching those of zinc dialkyldithiophosphate (ZDDP): the four‐ball wear‐scar diameters, d 30 min/294 N, with dihydroxydocosanoic acid, ZDDP, and 400 neutral base oil are 0.36, 0.35, and 0.62 mm, respectively. In order of effectiveness the antiwear ability of the C22 acids is: 13,14‐dihydroxydo‐cosanoic acid (I) 13(14)‐mono‐hydroxydocosanoic acid (II) docosanoic acid (III), showing that their antiwear properties are remarkably improved after introduction of the hydroxy group into fatty acids. Work on dihydroxy acid as an antiwear agent is not much reported in the literature up to now. In the present work, it was verified with infrared spectroscopy that polyester is formed on the rubbing surfaces with I and II by tribochemical reaction. An oxygen‐rich protective film on the rubbing surfaces was identified with Auger Electron Spectroscopy analysis. These results are identical to the high oxygen‐containing polyester film shown by IR analysis. It is preliminarily confirmed that the functional antiwear mechanism is, principally, the formation of a polymeric friction film on the rubbing surfaces.
Seizure resistance of phosphated coatings: Influence of carbon content and metallurgical structure of plain carbon steels
Authors: Adjerid S. , Hivart H. P. , Bricout J.‐P. , Oudin J. , Traisnel M. 
Published: July 2006

AbstractVariables which affect the seizure resistance of zinc phosphate coatings on steel, as used in cold forging, are studied by considering the influence of carbon content and metallurgical structure of a set of plain carbon steels. A seizure test, that is particularly well suited to evaluating the mechanical strength of phosphate‐stearate coatings, has been previously developed by the authors. Test results based on seizure occurrence are related to the effective phosphate bonding and to lubricant reactive effects. The results obtained show that seizure resistance of annealed plain carbon steel is optimal for carbon contents in the range of 0.38 ˜ 0.48% C. In this case, the phosphate structure is very fine and very dense, and consists of mixed needle and block crystals. Phosphate coating weight is also higher. The studies of metallurgical structures of steel show that highest seizure resistance is obtained for spheroidised structure. In this case, the phosphate coating weight is low and cannot be taken into account in characterising the efficiency of the phosphate coating.
Lubrication modes and the IRG transition diagram
Authors: Schipper D. J. , De Gee A. W. J. 
Published: July 2006

AbstractThe relationship between a Lubrication Mode Diagram (LMD) for concentrated contacts (LCC's) and the ‘IRG transition’ diagram has been studied. In addition, scuffing results, obtained by the IRG (International Research Group) have been analysed, as well as the results of scuffing tests performed by different workers using a two‐disc apparatus.It has been found that in Region I of the IRG transition diagram, three sub‐regions can be distinguished, representing elastohydrodynamic lubrication, mixed lubrication, and boundary lubrication, respectively. Thus, the IRG transition diagram is not comparable to a ‘lubrication mode diagram’. Furthermore, it has been found that failure of LCC's by scuffing most frequently occurs under conditions of mixed lubrication. Therefore, scuffing criteria based upon the assumption that the load at failure is carried entirely by the micro‐contacts are doubtful, and probably wrong.