bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis and tribological behaviour of boron‐nitrogen‐modified fatty acid water‐based lubricant additives
Authors: Hua Fang Jin , Bo‐Shui Chen , Lin Dong , Jiu Wang , Wei‐Jiu Huang 
Published: July 2006

AbstractA new type of boron‐nitrogen‐midified fatty acid as a water‐based lubricant additive was prepared and the chemical structure characterised by infrared spectroscopy. The tribological properties of the additive in water were evaluated using friction testers. The morphologies and tribochemical species of worn surfaces were analysed by means of X‐ray photoelectron spectroscopy (XPS). The results show that the additive is very good at increasing the losdcarrying capacity and the antiwear and friction‐reducing properties of wter. A lubrication mechanism is inferred in which a lhigh‐strength adsorption film and a tribochemical reaction film form on the rubbing surfaces as a resuly of the carrier effect of long‐chain fatty acid molecules, the high reaction activities of nitrogen, and the electron deficiency of boron, as well as the interactions of these factors.
Synergistic effect of antiwear additives and antioxidants in vegetable oil
Authors: Minami I. , Mimura K. 
Published: July 2006

AbstractCertain vegetable oils have been recognised as promising candidates for environmentally friendly lubricants. Their lubricity can be optimised using antiwear additives. However, decomposition of the additives, accompanied by auto‐oxidation of the vegetable oils, has been found to occur. In other words, the antiwear additives may degrade in vegetable oils, and give less oxidative stability. In order to understand the mechanism, oxidation testing of a vegetable oil was performed by monitoring the peroxide value (POV). It was observed that POV increases as soon as oxidation starts. The value reached 1400–1500 ppm within 50 h of reaction time. Then it decreased to an equilibrium value of 400–500 ppm within 200 h. Antioxidants to prevent peroxide generation were examined. Phenolic antioxidants and zinc dialkyldithiocar‐bamate exhibited good results with regard to preventing peroxide generation, whereas aromatic amines gave poor results. A synergistic effect that prevents the decomposition of the antiwear additives was found.
The effects of lubricant additives on wear and scuffing resistance of copper alloys under boundary conditions
Authors: Sheng Yu Meng , Rao Ming Yuan 
Published: July 2006

AbstractThe effects of lubricant additives on alloy composition and structure, and on the wear and scuffing resistance of copper alloys, were investigated. The copper alloys used were Sn bronze, Sn‐Zn‐Pb bronze, Al‐Fe bronze, and Si‐Mn brass. The base oil used was straight mineral oil. The additives used were dimer acid, phosphonate ester, sulphide olefine cotton‐seed oil, ZDDP and n‐dibutyl phosphite. The test results revealed that Si‐Mn brass shows the highest resistance to wear and scuffing, and Sn‐Zn‐Pb the lowest. It also revealed that oiliness additives are superior in wear and tear scuffing resistance to EP additives, especially sulphur‐containing additives. The authors also noted that copper alloys show good resistance to wear and scuffing when coupled with a polished steel surface.
Mechanisms of additive effectiveness
Authors: Hsu S. M. , Pei P. , Ku C. S. , Lin R. S. , Hsu S. T. 
Published: July 2006

AbstractDiscusses the nature and extent of base oil‐additive and additive‐additive interactions. The first interaction is in the bulk oil phase, where solution chemistry is involved. The second interaction occurs at the wear surfaces. Various experimental techniques (DSC, TFOUT, FRT, Four ball) were used to measure interactions. In an examination of base oil‐additive‐interactions on oxidation stability, various species of base oils exert a strong influence on the performance of antioxidants. In additive‐additive interactions, the data suggest a strong concentration of dependent interaction patterns among the various additives and the base oils. Mechanistic studies are recommended to elucidate some of the observed phenonema.
Prediction and prolongation of the useful life of industrial oils under operational conditions
Authors: Ivanov S. K. , Aleksandrov V. S. 
Published: July 2006

AbstractReports work on increasing the operational life of transformer oils by reducing oxidation, and looks at the possibilities of evaluating the action of metal‐deactivating additives, and new combinations of inhibitors. The paper also examines the possibilities for making predictions of the useful working life of transformer oils in the presence of synergistic inhibitors.
Evaluating thermal and thermooxidation stability for lubricating oils via microscale methods
Authors: El Naga H. H. Abou , Salem A. E. M. 
Published: July 2006

AbstractDifferential thermal analysis (DTA) and thermogravimetry (TG) methods have been developed to evaluate the thermal and thermooxidation stability of different lubricating oils. Measurements are carried out either by heating the oil sample at a constant rate (direct programme) or by keeping it at a fixed high temperature (isothermal programme). Oxygen at a constant flow rate is used for thermooxidation measurements. Tested samples included different viscosity grades: neutral base oils, unadditivated lubricating oil blends, and industrial oils. The mechanism of thermal decomposition for ZDDP and the estimation of its optimum concentration was also considered.
Changes in friction and wear performance caused by interactions among lubricant additives
Authors: Rounds Fred 
Published: July 2006

AbstractEngine oil additives generally fall into one of two general categories: those that affect bulk oil properties and those that affect the surface properties of lubricated parts. Interactions among surface‐active additives can lead to less‐than‐expected lubricant performance. Laboratory friction and wear test results are presented to illustrate the changes in lubricant performance that interactions among additives can cause. Some possible explanations are proposed.
Additives for metalworking lubricants ‐ a review
Authors: Kajdas C. 
Published: July 2006

AbstractThis paper is presented as an introduction to various specific problems associated with metalworking additives, especially that related to their modes of action. It describes various chemicals used as specific additives for metalworking lubricants. The introductory part of the review deals with general lubricant types for both metal‐forming and metal‐cutting processes. The section dealing with types of additives used for metalworking lubricants is followed by a section on the chemistry of these additives. The detailed review is connected with boundary lubrication additives for water‐based liquids and oil‐based lubricants. Corrosion and antimicrobial agents are discussed as well. Other additives are described more generally.
Elastohydrodynamics and failure prediction
Authors: Cheng H. S. 
Published: July 2006

AbstractMany rolling and sliding contacts in industrial machineries are lubricated elastohydrodynamically to mitigate friction and wear. Predictions of tribological failures and performance have been greatly enhanced in the past two decades due to advancements in elastohydrodynamics. In this paper, the major physical features and principles of elastohydrodynamic lubrication (EHL) along with the major modes of tribological failures are summarized, first, for these contacts. Brief discussions are given to current predictability of lubricant film thickness, contact pressure, temperature, and friction in elastohydrodynamic contacts, and how these variables are used in predicting contact fatigue life and the threshold conditions for sliding failure.
Structural aspects of European and American diesel engine piston deposits
Authors: Covitch Michael J. , Richardson John P. , Graf Robert T. 
Published: July 2006

AbstractThe formation of carbonaceous deposits on upper lands and ring grooves of diesel pistons is believed to be at least partially responsible for excessive cylinder bore wear and loss of oil control in field service. A properly formulated diesel lubricant has, among other performance characteristics, the ability to control piston deposits, thereby improving overall engine performance.
A study of grease film thicknesses in elastorheodynamic rolling point contacts
Authors: Bordenet L. , Dalmaz G. , Chaomleffel J‐P , Vergne F. 
Published: July 2006

AbstractAn elastorheodynamic analysis and a numercial solution are presented for grease film thicknesses in rolling point contacts for fully flooded, isothermal and steady state conditions. The contact surfaces are smooth and a grease four‐parameter rheological model is considered. A modified Reynolds equation is established and a complete numerical solution, including surface deformations, piezoviscous, and compressional effects is given.
An ‘in lubro’ study of viscosity index improvers in end contacts
Authors: Wardle R. W. M. , Coy R. C. , Cann P. M. , Spikes H. A. 
Published: July 2006

AbstractPolymeric viscosity index (VI) improver solutions in oils suffer from both temporary and permanent viscosity losses in high shear hydrodynamic and elastohydrodynamic (EHD) contacts. In some cases in EHD contacts, these losses can be so severe that the additive makes negligible contribution to oil film thickness.This paper describes the use of a combination of optical interferometry and FTIR micro‐reflectance spectroscopy to measure the effectiveness, and to observe directly the behaviour, of conventional VI improver solutions within rolling and sliding EHD contacts. The study shows the extent to which polymers enter EHD contacts and charts the degradation that they suffer therein.
Application of a new concept to detergency
Authors: Georges J. M. , Loubet J. L. , Alberola N. , Meille G. , Bourgognon H. , Hoornaert P. , Chapelet G. 
Published: July 2006

AbstractThe purpose of this paper is to describe a new concept in the detergency phenomenon for engines. It is well known that oil detergency is associated with additive adsorption, neutralisation of the acid formed, and insoluble encapsulation. However, the literature is poor in relation to the mechanical properties of oxidised oil film created during the coking process. Basic experiments taking a pure base oil and an overbased additivated oil show clearly two different types of mechanical behaviour in the burned oil film. The base oil creates a ductile film very adherent to the substrate. Conversely, the additivated film can be very brittle and shows clearly cohesive cracks followed by adhesive film‐substrate cracks. A physico‐mechanical model is proposed to explain the role played by the internal stress developed in the film during its gel state. This analysis leads to a simple thermooxidation laboratory test, where mechanical behaviour is evaluated by peeling and is correlated with engine detergency.
On the efficiency of additives during boundary lubrication with special regard to the processes of forming reaction layers
Authors: Meyer K. , Dabrowski J. R. , Kloss H. 
Published: July 2006

AbstractThe process of forming reaction layers of selected compounds is investigated regarding the chemical reactivity of different lubricants. The following lubricants were used as test oils: paraffin solutions with DBDS, ZDTP, acenaphthylene and limonene. Their influence on tribological behaviour is described for different conditions of friction. Relations between layer‐forming behaviour and layer properties on the one hand, and tribological properties on the other hand, were shown by chemical layer profile analysis and other methods.
A strategy for the development of optimised lubricants
Authors: Dare‐Edwards M. P. , Gadd P. 
Published: July 2006

AbstractThe design of lubricants has traditionally relied on the use of single dimension constitution / performance or structure / property relationships. In this paper a strategy is described whereby consideration is given to the inherent property / property (physical and chemical) correlations that exist for fluid lubricants. Progress towards the development of optimised lubricants is then achieved by identifying the molecular structural or compositional traits associated with ‘extensions’ to or ‘deviations’ from the mainstream correlations. Some examples of the success of this novel strategy will be provided, and the directions of its further refinement briefly outlined.
Measurement of the influence of sliding velocity on oil film thickness in an elastohydrodynamic point contact
Authors: Isaksson O. 
Published: July 2006

AbstractExperiments have been carried out to measure the film thickness between a sapphire disc and a polished steel ball when slippage is permitted between the two surfaces. The velocity sum of the two surfaces was kept constant during the measurements. The method used to determine the oil film thickness in the contact zone is optical interferometry.It was observed that the change in minimum film thickness was slight. When the sliding velocity was increased, the decrease in central film thickness was considerably larger than that of the minimum film thickness. In addition, the two side lobes, in which the minimum film thickness area occurs, were observed to become flatter as the sliding velocity was increased.
The structure of grease via electron microscopy and image analysis
Authors: Shuff P. J. , Clarke L. J. 
Published: July 2006

AbstractMany of the insolubles that are essential to the structure of lubricating greases are too small to be usefully imaged in the optical microscope. The higher resolution of the electron microscope is necessary to examine the thickener and additive morphology that contribute so much to the performance of modern greases. However, the high vacuum requirements of these instruments mean that the oil component of grease should not be introduced into the microscope at ambient temperatures. Techniques have been developed to remove the oil prior to examination, or to reduce its vapour pressure to a negligible level. A number of such techniques which have proved to be of value for both the scanning (SEM) and transmission (TEM) microscopes are described and illustrated. The distribution of the thickener fibres can now be measured and analysed by an image analysis procedure from the images of freeze‐fracture TEM replicas.
The use of chemiluminescence in determining the thermal and oxidative stability of motor oils
Authors: Ivanov S. K. , Kalitchin Z. D. , Aleksandrov V. S. 
Published: July 2006

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 temperatures.
Development and application of thermo‐oxidation laboratory tests. Correlations with engine lubricant specifications
Authors: Bourgognon H. , Piquemal A. , Rodes C. , Benard F. , Alberola N. , Vassel A. , Georges J. M. 
Published: July 2006

AbstractLaboratory simulation tests are an important stage in the selection of engine lubricants. Where these tests are brief and repeatable, they allow numerous studies and can provide a wide range of information. They are all the more valuable if they have a close degree of correlation with a specification test.The IIID high temperature oxidation test, the ME 1517 oxidation laboratory test and the Renault 30 diesel engine test are examples of specifications for the formulation of engine lubricants. The aim of the present study has been to find or develop a brief, repeatable laboratory test for these specifications and to establish a correlation between the test and the specification.Data obtained show satisfactory correlations between the TFOUT (Thin Film Oxygen Uptake Test) and the IIID sequence, the open oxidation laboratory test COST (24 h) and ME 1517 (192 h), and the ELF/ECL microcoking test and the Renault 30 turbo diesel test.
The wear behaviour of steel lubricated by some oxygen‐containing derivatives of heterocyclic nitrogen‐containing compounds (HNCC) under boundary lubrication conditions
Authors: Wei D. , Song H. 
Published: July 2006

AbstractThe effect of an oxygen‐containing group on the wear behaviour of heterocyclic nitrogen‐containing compounds (HNCC) have been investigated on a four‐ball machine and a SRV tester. The preliminary results show that the substitution of the hydroxyl group and aldo‐group significantly increases the antiwear effectiveness of the parent compounds. However, the alkyloxyl group involved in some HNCC does not improve the wear performance of HNCC.In order to get a better understanding of the role of oxygen‐containing groups in wear chemistry, a pair of compounds, quinoline and 8‐hydroxyquinoline, were chosen for further study. The analytical results of worn surfaces, wear debris and deposits showed that the difference in sliding behaviour between quinoline and 8‐hydroxyquinoline can be related to chemical reaction at the rubbing surfaces involving metal, HNCC and a hydroxyl group in HNCC or oxygen dissolved in the base stock. Under the same test conditions, these compounds, which are similar in chemical structure, give quite different reaction products. Quinoline is decomposed and oxidised by oxygen dissolving in the base stock to form a carboxylate function (soap). In the case of 8‐hydroxyquinoline, partial surface products are converted to higher molecular species, probably due to the catalytic action of fresh metal surface being exposed by rubbing. The new species, with higher molecular weight, probably belong to a kind of friction polymer, function as a boundary lubricant, and dramatically increase the antiwear effectiveness of the compound. The antiwear mechanisms of oxygen‐containing derivatives of HNCC are also discussed.
The overbasing of detergent additives: The behaviour of promoters and determination of factors controlling the overbasing reaction
Authors: Belle C. , Gallo R. , Jacquet F. , Hoornaert P. , Roman J. P. 
Published: July 2006

AbstractThe mechanism of overbasing of additives used in lubricating oils is studied. Overbased calcium sulphonates, the most widely used, are examined. Although the geometrical and physical nature of colloidal carbonate particles has been well studied, little is known about the fundamental aspects and mechanism of the overbasing process. In this paper, assessment of the physical and/or chemical nature of the reaction is made from equations related to the chemical engineering model of the shrinking spherical particle. The results show that the overbasing process is under diffusion control, and the chemical reaction is not determining.
Effect of KMnO4 oxidant additive on solid lubrication of lead‐graphite and silver‐graphite composites
Authors: Umeda Kazunori , Enomoto Yuji , Matsumoto Yukio 
Published: July 2006

AbstractThe purpose of this investigation is to understand the role of KMnO4 as an oxidant additive on the lubrication properties of a soft metal + graphite composite system, under flat contact sliding conditions where the sliding surfaces interact less with the atmosphere. The sliding tests were made using a ring‐on‐disk machine, lubricated with Pb or Ag + graphite composite containing different amounts of KMnO4 additive.The results showed that the addition of KMnO4 in the composites reduced the friction in air up to temperatures of 500°C. The coefficient of friction was as low as 0.1. This is probably due to the fact that KMnO4 decomposed during sliding to generate oxygen, which is effective in improving the lubricating ability of graphite. The optimum concentration of KMnO4 in the solid lubricants (graphite + KMnO4) was 5–10 vol.%. After decomposition of all oxidant additive in the composite, the coefficient of friction of the composites, however, rose to 0.2–0.3.
Study of microstructural transformation of overbased calcium sulphonates during friction
Authors: Giasson S. , Espinat D. , Palermo T. 
Published: July 2006

AbstractColloidal dispersions of calcium carbonate stabilised by calcium alkylaryl sulphonates are detergent additives used in lubricant oils, and have particular effects on wear processes. In the present work, such additives were investigated using Small Angle X‐ray Scattering technique (SAXS). Different scattering intensity simulation and curve‐fitting programs were used to determine the size of the overbased calcium sulphonate particles and to characterise the interactions between them. In the additive oil (11 wt% CaCO3), the overbased calcium sulphonates appear as polydispersed micelles having an average calcium carbonate core radius of 2.0 nm. Moreover, an attractive potential between the micelles of less than kT has been observed. In order to investigate the effect of friction constraints on the additive, friction tests were performed on a rotative tribometer. Under specific conditions, there was a decrease in friction force arising from the formation of a viscous deposit. According to the differentanalyses, the viscous deposit contained more polydisperse particles, which did not have the same structure as those contained in the original additive. These particles consisted mainly of calcium carbonate. Some sulphonate chains were expelled from the friction zone. Moreover, the particles contained in the deposit interact with a potential on the order of 10 kT. Wide Angle X‐ray Scattering (WAXS) confirmed the presence of highly crystalline calcite. Moreover, the effects of pressure and the presence of water were studied. The pressure contributes neither to an increase in particle size nor to a crystallisation phenomenon. However, the presence of water in the additive oil alters the interactions between the micelles. The potential observed is 8.2 kT and suggests that the water is a responsible parameter for the agglomeration of micelles consisting of the viscous deposit.
Viscometric properties of a multigrade motor oil in relation to its bright‐stock content
Authors: El Naga H. H. Abou , Bendary S. A. 
Published: July 2006

AbstractViscometric properties for a multigrade motor oil with SAE 20W/50 viscosity grade were studied in the presence of different viscosity index improvers. The neat base blends contained increasing percentages of a bright‐stock.Measured viscometric properties for both the neat and VI improved blends included the following: kinematic viscosity, viscosity increase by incorporation of a VI improver, viscosity index, specific viscosity and thickening tendency. These measurements were carried out over a wide temperature range.Increase of the bright‐stock content showed that most of the VI improvers behave as thickeners. Polyalkylmethacrylate and styrene‐isoprene copolymers were found to be the only exception from such behaviour for the VI improvers.
Lubricant rheological properties at high pressure
Authors: Bair Scott , Winer Ward O. , Qureshi Farrukh 
Published: July 2006

AbstractVarious types of rheometric apparatus have been developed to study and measure the shear stress behaviour of liquid lubricants. Elastohydrodynamic (EHD) lubrication is better studied with a high‐pressure rheometer which allows independent control of temperature, pressure, and shear strain. With this, the authors propose an improved relation for the variation of viscosity through the glass transition, and present refined relations for shear modulus and limiting shear stress.