bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of surface roughness on the lubrication properties of the piston ring and cylinder of an engine, and calculation of lubrication and power loss analysis of piston‐ring pack of a S195 diesel engine
Authors: Gui C. L. , Liu K. 
Published: July 2006

AbstractThe effect of surface roughness on lubrication of piston ring and cylinder is examined. In particular, the temperature effect is considered, and a model proposed to overcome shortcomings in the previous mathematical model. Further, film thickness was measured by transducer capacitance method in a S195 diesel engine. The results found are consistent with theoretical results. In addition, the authors show quantitatively the value of friction power losses of the ring package of a S195 diesel engine.
Antiwear actions of additives in solid dispersion
Authors: Morizur M. F. , Teysset O. 
Published: July 2006

AbstractIn this paper we compare the action mechanisms of different ‘non‐soluble’ additives: a dispersion of potassium triborate and overbased detergents formed by calcium carbonate, or borate aggregates dispersed by a detergent. These additives act by producing a deposit issued from their mineral phase, on the friction surface. With the potassium triborate, a solid film of borate, bound to the metal, is only detected on a negatively‐polarised surface or in conditions of severe wear when friction surfaces have been activated by abrasion. On the contrary, with the overbased detergent, a solid film is always detected on the friction surfaces, even without activation by abrasion. This additive is decomposed in the contact zone by the effect of the elevated pressure. The present study shows that the method of placement in suspension of the inorganic phase by the detergents is important. It offers the advantage of forming deposits only in the friction zone, instantly and independently of the type and state of the friction surface.
Carbonyl peak index technique in the study of lubricant oxidation
Authors: Maduako A. U. C. , Ofunne G. C. , Ojinnaka C. M. 
Published: July 2006

AbstractA technique known as the Carbonyl Peak Index (CPI) is used to assess the relative oxidation stabilities of two competing grades of commercial automotive crankcase oils, their base oils, and the oxidation characteristics resulting from oil/metal interactions. The CPI provided empirical data from the infrared spectra which enabled a more lucid explanation of the oil soluble acidity and sludge deposition characteristics of the oils. A combination of these parameters has confirmed that the hydrocarbon type composition of the oils gave some stability to the fully formulated monograde oil. Consequently, the monograde base oil was found to possess a greater stability towards oxidation than the multigrade base oil under the conditions of test. However, the fully formulated oils were found to be more stable than the base oils, mainly due to the added antioxidants. Metals in the oils acted as antioxidants initially, but later turned to pro‐oxidants. The reversal of metal action from inhibition to autooxidative catalysis was also found to be base‐oil hydrocarbon‐type dependent and this has been related to the natural antioxidant capacity of the oils.
The influence of base oil properties on the efficiency of action of ZDDP‐type additives
Authors: Kulczycki A. , Kajdas C. 
Published: July 2006

AbstractThis paper deals with the analysis of the influence of base oil viscosity on the ability of ZDDP‐containing lubricants to form protective layers (especially antiwear layers). The chemical structure of additives used was characterised according to their thermal stability, determined by differential scanning calorimetry (DSC). The additives were added to base oils of various viscosities. The prepared lubricants were tested using a four‐ball machine, and analysed by DSC.The relationships between base oil viscosity and seizure load (Pt), weld load (Pw) and DSC test results are presented and discussed. The mechanism of interaction between ZDDP and the base oils was analysed by the use of a mathematical model.
Effect of amines on the antiwear properties of P‐containing compounds as oil additives
Authors: Wan Yong , Liu Weimin , Ren Tianhui , Xue Qunji 
Published: July 2006

AbstractThis paper reports a study on the effects of concentration and the molecular structure of amines on the antiwear properties of TBP, TCP and TBPi, evaluated with a four‐ball machine. It was found that amines reduce the antiwear properties of P‐containing additives in the order primary>secondary>tertiary amine, and a critical amine concentration exists at which P‐containing additives lose their antiwear properties. XPS analysis indicated that the competitive adsorption of amines onto the rubbed surface causes a reduction of the antiwear properties of P‐containing additives.
Studies on additive‐additive interactions: Effects of dispersant and antioxidant additives on the synergistic combination of overbased sulphonate and ZDDP
Authors: Ramakumar S. S. V. , Aggarwal Neelam , Rao A. Madhusudhana , Sarpal A. S. , Srivastava S. P. , Bhatnagar A. K. 
Published: July 2006

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.1 In 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 and 31p‐NMR spectroscopic analyses on interactive additive pairs, namely, ZDDP‐PIBS and ZDDP‐antioxidant, indicated the formation of association complexes and hydrogen bonding respectively.
The performance and antiwear mechanism of S‐containing organic borate as an oil additive
Authors: Liu Weimin , Jin Zhishan , Xue Qunji 
Published: July 2006

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 borate is proposed.
Tribochemistry and the development of AW and EP oil additives — a review
Authors: Xue Qunji , Liu Weimin 
Published: July 2006

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 proposed.
An infrared analysis method to determine the aromatic carbon content of mineral lubricant base oils based on correlation with carbon‐13 NMR aromaticities
Authors: Van De Ven Adri M. C. , Jansen Leen , Heijer Joop Den 
Published: July 2006

AbstractA widely used method to determine base oil aromaticity was introduced by G. Brandes in 1956 and is based on a correlation between the infrared aromatic absorption band at 1610 cm−1 and the aromaticity determined by the n‐d‐M method. Accurate and absolute aromaticities can be measured by carbon‐13 NMR but, infortunately, this technique is not suitable for routine analysis.The aromaticities measured by NMR are almost invariably significantly lower than those obtained by Brandes' method. In this study, the areas of the infrared aromatic bands at 1610 and 815 cm−1 of over 70 base oils with aromaticities ranging from 1–16% were correlated by multilinear regression with their carbon‐13 NMR aromaticities. An equation to calculate the aromaticity from infrared absorptions was derived. These aromaticities show an excellent match with carbon‐13 NMR data. This new infrared method can be applied as a fast and convenient base‐oil quality control tool.
The effect of contamination particles on lithium grease deterioration in sealed ball bearings
Authors: Jin Xue 
Published: July 2006

AbstractWith advanced analytical methods, the effects of four kinds of contamination particles, including Fe, Cu, and MoS2 powders, on lithium grease deterioration in sealed ball bearings has been studied. As the deterioration process of grease at high temperatures is triggered by chemical factors, so a number of tests have been conducted at 125°C to investigate its effect upon the deterioration process of grease, with various particles, under the condition of a bearing speed of 3000 r/min. As well as the deterioration phenomena, the mechanism of the deterioration of lithium grease in a sealed bearing with particles is also discussed in detail.
A spectroscopic study of a copper surface under boundary lubrication: I. Chemisorbed stearic acid multilayers
Authors: Hu Zu‐Shao , Wang Pu Sen , Hsu Stephen M. 
Published: July 2006

AbstractThe thickness of chemisorbed stearic acid films on copper surfaces was deduced by Fourier transform infrared (FTIR) spectroscopy and Auger electron spectroscopy (AES). The chemisorption was detected by FTIR from the carboxyl (COO) asymmetric stretching band at 1585 cm−1. Multilayer growth was observed by monitoring the intensity increase in the asymmetric CH2 stretching mode at 2915 cm−1. The growth of the chemisorbed layer was found to depend on the concentration of the stearic acid/hexadecane solution. The chemisorption kinetic profile had a step‐function due to the change in the number of layers. High carbon concentration in Auger spectroscopic characterisation indicated that the surface was coated with a stearic acid film. AES depth profiling analysis supports this step‐function model and agrees well with the FTIR results.
The energy pulse: A new wear criterion and its relevance to wear in gear teeth and automotive engine valve trains
Authors: Plint M. A. , Alliston‐Greiner A. F. 
Published: July 2006

AbstractThe paper follows an earlier study in which the various standard test procedures for assessing the extreme pressure and anti‐wear properties of lubricants were classified and evaluated in terms of a number of parameters.The significance of the frictional heating energy was apparent and a new parameter, the energy pulse, was proposed. This concept has been further developed in the present paper and applied to an analysis of contact conditions and patterns of wear in gears and valve trains.
Antioxidant properties of engine oil detergent additives
Authors: Vipper A. B. 
Published: July 2006

AbstractThe antioxidant properties of engine calcium sulphonate, phenate and salicylate detergent additives were investigated. Their influence on engine oil oxidation both in the presence of metallic copper, oil‐soluble copper compounds, and without any catalyst, was studied. The influence of the detergent type and its basicity on oil antioxidant properties was determined. The specific influence of the co‐operative action of detergent additives and zinc dithiophosphate on the antioxidant properties of engine oil formulations with these additives was established. The results obtained revealed various new patterns concerning the oil oxidation process, and allowed us to characterise the process of depletion of detergent additives during oil ageing.
Tribological performance and mechanism of action of overbased detergents
Authors: Vipper A. B. , Cook S. J. , Karaulov A. K. , Moreton D. J. , Mischuk O. A. , Leahy R. 
Published: July 2006

AbstractThe antifriction properties of calcium phenate‐, sulphonate‐ and alkylsalicylate‐type detergent additives were investigated. The influence of the detergent type and its basicity on engine oil antifriction properties was determined. The tribological performance of different detergents was characterised by laboratory methods. Auger spectroscopy was used for surface layer composition and thickness determination. The experimental data allowed the mechanism of action and the tribological performance characteristics of overbased detergents to be more precisely identified.
Biotribology: Friction, wear, and lubrication of natural synovial joints
Authors: Furey Michael J. , Burkhardt Bettina M. 
Published: July 2006

AbstractStudies have been carried out over the past several years to explore possible interconnections between tribology — the study of friction, wear, and lubrication — and arthrology, more specifically, mechanisms of synovial joint lubrication and degeneration. The focus of this paper is on the tribological behaviour of natural and so‐called ‘normal’ synovial joints. A separate paper deals with possible connections between tribology and degenerative joint disease (e.g., osteoarthritis).The purpose of this paper is fourfold: (1) to present a summary of salient work on mechanisms of synovial joint lubrication; (2) to review the key findings of our in vitro wear studies made with bovine articular cartilage; (3) to discuss the significance of the cartilage wear studies in relation to existing joint lubrication theories; and (4) to describe a new device being used for studies of cartilage‐on‐cartilage deformation, friction, wear and damage under in vitro conditions.
Antifriction properties of calcium phenate‐type detergents used in marine cylinder lubricants
Authors: Vipper A. B. , Cook S. J. , Karaulov A. K. , Leahy R. 
Published: July 2006

AbstractThe antifriction properties of calcium phenate‐type detergents of different lubricity were investigated by laboratory methods. Simulation of the operating environment in super‐long‐stroke marine diesel engines was achieved using concentrated sulphuric acid. The influence of the tested additives on engine oil antifriction properties was determined after their being mixed with acid. The tribological performance of oil samples with 50 and 70 TBN values was characterised by testing on a friction machine, and by thickness determination of friction surface layers using Auger spectroscopy. It was found that the effectiveness of antifriction action of the detergents tested depends on the thermal stability of the lubricating layers, the temperature at which the destruction of the boundary lubricating layers occurred, and the thickness of secondary structure layers in the metal surface of the friction pairs.
The non‐Newtonian effect of temperature on hydrodynamic lubrication failure
Authors: Guangjun Zhang , Ping Huang , Shizhu Wen , Huirong Meng 
Published: July 2006

AbstractThe influence of temperature on the rheological characteristics of lubricants has been investigated by analysing the viscosity‐temperature relationship and energy equation of lubricants. The constitutive equation, which describes the non‐Newtonian properties of lubricants caused by thermal effects, is founded and coupled with equations of continuity and momentum of the fluid to calculate the load‐carrying capacity in hydrodynamic lubrication. The numerical solutions show that lubricants have ultimate shear strength as a result of the non‐Newtonian effect of temperature, which leads to the oil film having limiting load‐carrying capacity. The mechanism of film failure in hydro‐dynamic lubrication is also studied preliminarily in this paper.
On the hydrodynamic lubrication analysis of piston rings
Authors: Esfahanian Mohsen , Hamrock Bernard J. , Elsharkawy Abdaliah A. 
Published: July 2006

AbstractA theoretical hydrodynamic lubrication analysis of piston rings is presented. A numerical scheme is developed to solve the Reynolds' equation and the load equilibrium equation simultaneously. The hydrodynamic effects are examined in detail by considering solutions to the problem of lubricating the top compression ring in a two‐stroke diesel engine. The minimum film thickness is computed throughout a complete cycle. The pressure profiles and film shapes at different crankshaft angles are presented. In the method proposed, the camtation boundary condition within the lubricated conjunction is included in the analysis.
A study of the tribological behaviour and mechanism of actoin of bismuth dialkyldithiophosphate
Authors: Chen L. , Dong J. , Chen G. 
Published: July 2006

AbstractThis paper discusses the preparation of bismuth dialkyldithio‐phosphate as an oil‐soluble antiwear and extreme pressure additive for lubricants. Its tribological performance when added to an ISO VG32 mineral oil was evaluated on a four‐ball tester and a ring‐on‐block machine. The relationships between its performance and the concentrations are also given, and are compared with those of zinc dialkyldithiophosphate (ZDDP). The results show that the compound not only possesses good antiwear and friction‐reducing abilities, but also has a higher load‐carrying capacity than ZDDP. The mechanism of action of the additive was studied by surface analysis. A scanning Auger microprobe revealed a high bismuth content in the rubbing surface layers, and X‐ray photoelectron spectroscopy detected the formation of various chemical species including organic films, metallic bismuth, bismuth oxide, and bismuth sulphide. The mechanism of action is postulated on the basis of these results.
Substrate surface energy effects on a liquid lubricant film at nanometre scalesubstrate surface energy effects on a liquid lubricant film at nanometre scale
Authors: Jianbin Luo , Shizhu Wen , Xuanyu Sheng , Li Lawrence K. Y. 
Published: July 2006

AbstractIn this paper is discussed the effect of the physical characteristics of substrate surfaces on the lubrication properties of thin films at nanometre scale. Different coatings with different surface energies have been formed on the surface of a steel ball by means of plasma assisted sedimentation (PAS). The ball was put in a pure rolling system in point contact, where the lubricant film is measured by relative optical interference intensity (ROII). Experimental results show that the film thickness is closely related to the substrate surface energy when the film is in the nanometre scale, and that the combined surface roughness in the contact region is closely related to the liquid lubricant film thickness and the contact pressure. The thinner the film and the higher the contact pressure, the smaller will be the combined surface roughness. Lastly, the relationship between critical film thickness and its influencing factors is discussed.
A description of the lubricating action of the tribo‐active components of cutting fluids
Authors: Godlevski V. A. , Volkov A. V. , Latyshev V. N. , Maurin L. N. 
Published: July 2006

AbstractA multistage mechanism of lubrication layer formation during cutting is described and the necessary conditions for the formation of a lubrication layer are formulated. It is considered that the process of physical adsorption of the tribo‐active components of the cutting fluid in the contact zone between tool and chip during metal cutting is one step in a multistage process which occurs in the interface capillary system. A mathematical model describing simultaneous diffusion and adsorption of tribo‐active components in a single interface capillary is proposed. Some parameters for a model determining the efficiency of the lubricating action of surface‐active additives are also proposed.
An analysis of the mechanisms of grease lubrication in rolling element bearings
Authors: Cann Philippa , Lubrecht A. A. 
Published: July 2006

AbstractThere are over eighteen billion bearings in use in the world, and most are grease lubricated. Grease is chosen for a variety of reasons: it gives low friction, is easily confined, and has a long lubricating life at low cost. In many applications, the grease is expected to lubricate effectively over a wide range of conditions and for extended periods. For such applications, lubricant failure leads to instantaneous and rapidly increasing damage of the components and eventually breakdown. Thus, an improved understanding of the fundamental aspects of grease lubrication has far‐ranging technical and economic implications. Despite the overwhelming importance of this subject, very little is known about the mechanisms of grease lubrication and the relationship between composition, lubrication performance, and life. This paper attempts to summarise current understanding of grease lubrication mechanisms in rolling element bearings and to consolidate the different aspects of this complex topic.
Preparation and tribology of aerogel silica and alumina‐silica as lubricant oil additives
Authors: Dong J. X. , Hu Z. S. , Chen G. X. 
Published: July 2006

AbstractAerogel silica and an aerogel mixture of aluminium and silica were prepared using the ethanol supercritical fluid drying technique. Their physical properties were characterised using XRD, transmission electron microscopy, (TEM), and N2 adsorption. The tribological properties of a 500 SN oil containing the aerogel and a dispersing agent were evaluated using a four‐ball machine and a block‐on‐ring tribotester. Results indicated a greater wear resistance and load‐carrying capacity and a lower friction coefficient than for the basic oil. In the oil, the aerogel worked by its deposition on the rubbing surface. Copper stearate was superior to dodecyl alcohol as a dispersing additive, and ultrasonic treatment helped promote the dispersion of the aerogel in oil. There existed an optimum ratio of aluminium isopropyl alcoholate to tetraethanol silicate. The corresponding aerogel mixture gave a maximum value of PE.