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Relevant bibliographies by topics / Boundary lubricants

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Academic literature on the topic 'Boundary lubricants'

Author: Grafiati

Published: 6 September 2023

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Journal articles on the topic "Boundary lubricants"

1

Kato, S., E. Marui, A. Kobayashi, and S. Senda. "The Influence of Lubricants on Static Friction Characteristics Under Boundary Lubrication." Journal of Tribology 107, no. 2 (April 1, 1985): 188–94. http://dx.doi.org/10.1115/1.3261018.

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Based on a new boundary lubrication model, the characteristics of lubricants under boundary lubrication at low sliding speed and low contact pressure such as in machine tool slideways are investigated in relation to surface topography. It is clarified theoretically and ascertained experimentally that the property of lubricants under boundary lubrication can be estimated by the newly defined appraisal coefficient of boundary lubrication property determined by the thickness and load carrying capacity of adsorbed lubricant film and the surface topography.

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2

Liu, Xiaoyan, and Per M. Claesson. "Bioinspired Bottlebrush Polymers for Aqueous Boundary Lubrication." Polymers 14, no. 13 (July 3, 2022): 2724. http://dx.doi.org/10.3390/polym14132724.

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An extremely efficient lubrication system is achieved in synovial joints by means of bio-lubricants and sophisticated nanostructured surfaces that work together. Molecular bottlebrush structures play crucial roles for this superior tribosystem. For example, lubricin is an important bio-lubricant, and aggrecan associated with hyaluronan is important for the mechanical response of cartilage. Inspired by nature, synthetic bottlebrush polymers have been developed and excellent aqueous boundary lubrication has been achieved. In this review, we summarize recent experimental investigations of the interfacial lubrication properties of surfaces coated with bottlebrush bio-lubricants and bioinspired bottlebrush polymers. We also discuss recent advances in understanding intermolecular synergy in aqueous lubrication including natural and synthetic polymers. Finally, opportunities and challenges in developing efficient aqueous boundary lubrication systems are outlined.

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3

Xu, Rong-Guang, and Yongsheng Leng. "Squeezing and stick–slip friction behaviors of lubricants in boundary lubrication." Proceedings of the National Academy of Sciences 115, no. 26 (June 13, 2018): 6560–65. http://dx.doi.org/10.1073/pnas.1805569115.

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The fundamental questions of how lubricant molecules organize into a layered structure under nanometers confinement and what is the interplay between layering and friction are still not well answered in the field of nanotribology. While the phase transition of lubricants during a squeeze-out process under compression is a long-standing controversial debate (i.e., liquid-like to solid-like phase transition versus amorphous glass-like transition), recent different interpretations to the stick–slip friction of lubricants in boundary lubrication present new challenges in this field. We carry out molecular dynamics simulations of a model lubricant film (cyclohexane) confined between molecularly smooth surfaces (mica)––a prototypical model system studied in surface force apparatus or surface force balance experiments. Through fully atomistic simulations, we find that repulsive force between two solid surfaces starts at about seven lubricant layers (n= 7) and the lubricant film undergoes a sudden liquid-like to solid-like phase transition atn< 6 monolayers thickness. Shear of solidified lubricant films at three- or four-monolayer thickness results in stick–slip friction. The sliding friction simulation shows that instead of shear melting of the film during the slip of the surface, boundary slips at solid–lubricant interfaces happen, while the solidified structure of the lubricant film is well maintained during repeated stick–slip friction cycles. Moreover, no dilation of the lubricant film during the slip is observed, which is surprisingly consistent with recent surface force balance experimental measurements.

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Arif, Mohammad, Saurabh Kango, and Dinesh Kumar Shukla. "Effect of slip boundary condition and non-newtonian rheology of lubricants on the dynamic characteristics of finite hydrodynamic journal bearing." Surface Topography: Metrology and Properties 10, no. 1 (January 11, 2022): 015002. http://dx.doi.org/10.1088/2051-672x/ac4403.

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Abstract In the present study, the influence of various slip zone locations on the dynamic stability of finite hydrodynamic journal bearing lubricated with non-Newtonian and Newtonian lubricants has been investigated. Linearized equation of motion with free vibration of rigid rotor has been used to find the optimum location of the slip region with maximum stability margin limit. It has been observed that bearing with interface of slip and no-slip region near the upstream side of minimum film-thickness location is effective in improving the direct and cross stiffness coefficient, critical mass parameter, and critical whirling speed. The magnitude of dynamic performance parameters with slip effect is highly dependent on the rheology of lubricant. Shear-thinning lubricants combined with slip boundary condition shows higher dynamic stability as compared to the Newtonian lubricants under the conventional boundary condition. For all considered rheology of lubricants, the dynamic stability of bearing with slip effect is improving by increasing the eccentricity ratio.

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Carré, D. J. "Perfluoropolyalkylether lubricants under boundary conditions: Iron catalysis of lubricant degradation." Journal of Synthetic Lubrication 6, no. 1 (April 1989): 1–15. http://dx.doi.org/10.1002/jsl.3000060102.

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Boiko, M., T. Boiko, and I. Kolesnikov. "Influence of aldol condensation processes on the formation of surface films during friction in ester lubricants." Journal of Physics: Conference Series 2131, no. 5 (December 1, 2021): 052037. http://dx.doi.org/10.1088/1742-6596/2131/5/052037.

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Abstract The boundary lubrication mode is usually implemented in conditions of low sliding speeds and high loads. The formation of strong boundary lubricating films under this friction mode determines the operability and durability of the friction units. It is believed that the formation of surface boundary films during friction includes the stages of the lubricant oxidation, and the aldol condensation reaction of oxidized molecules. As a result, high-molecular substances called “friction polymers” are formed. The paper studies the formation of surface films in the presence of substances with different reactivity in the aldol condensation and Claisen condensation reactions. Sunflower oil, bis (2-ethylhexyl) sebacate (DEHS), triisodecyl benzene-1,2,4-tricarboxylate (TC) were used as lubricants. It is shown by ATR IR-spectroscopy of that the common thing for the studied oils is that the C=O and C-O groups participate in the formation of boundary films in these oils. The addition of substances, active in aldol condensation reactions, into lubricants does not accelerate the formation of boundary films. Additives that can chemically interact with iron contribute to the dissolution of the surface oxide film and accelerate the formation of boundary layers. The formation of “friction polymers” occurs when the lubricant molecules interact with the metal surface.

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García-Miranda, J. Santos, Luis Daniel Aguilera-Camacho, María Teresa Hernández-Sierra, and Karla J. Moreno. "A Comparative Analysis of the Lubricating Performance of an Eco-Friendly Lubricant vs Mineral Oil in a Metallic System." Coatings 13, no. 8 (July 27, 2023): 1314. http://dx.doi.org/10.3390/coatings13081314.

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Eco-friendly lubricant research continues to increase since it has a comparative performance to commercial mineral lubricants to overcome the effects of environmental impact. However, the efficiency of these green lubricants depends on specific applications. In this study, we analyzed the friction and wear performance of a castor/sesame oil mixture as an eco-friendly lubricant and its comparison to a commercial mineral lubricant tested in a metallic system employed in bearing elements. For this purpose, AISI 8620 steel against ISO 100Cr6 was used as tribological pair. The friction and wear tests were carried out through a Tribometer of ball-on-disk configuration under boundary lubricating conditions, whereas the worn surfaces were investigated by using optical and electron microscopy. The physical properties and the rheological properties of the lubricants were also determined. The friction and wear performance between the eco-friendly lubricant and mineral oil were similar so that the CLE were comparable. The CLE values in terms of friction and wear ranged from 86% to 99.4%, respectively.

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Kobayashi, A., N. Unno, and T. Yonemoto. "Study on the Adhesion Force of Lubricants—Adhesion Force Characteristics Under Boundary Lubrication." Journal of Tribology 119, no. 1 (January 1, 1997): 107–11. http://dx.doi.org/10.1115/1.2832443.

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The mechanisms that generate adhesion forces in liquid lubricants are studied under various experimental conditions. These forces occur between two surfaces when they are detached in the normal direction under static boundary lubrication conditions. The adhesion force is not influenced by the speed at which the upper specimen is pulled up, but is influenced by the viscosity of the lubricant. The adhesion force under boundary lubrication is much greater than that under hydrodynamic lubrication, and it is closely related to the compressibility of the lubricant.

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Voronin, Serhii, Ivan Hrunyk, Bashir Asadov, Dmytro Onopreychuk, and Volodymyr Stefanov. "Study of the Process of Lubricant Application on the Friction Surface Using Aerosol Lubricators." International Journal of Engineering & Technology 7, no. 4.3 (September 15, 2018): 20. http://dx.doi.org/10.14419/ijet.v7i4.3.19546.

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The problem of calculation and forecasting main parameters of aerosol lubricators designed for applying lubricants on angled to the horizon friction surfaces e.g. the lateral surfaces of a rail and a wheel flange of railway rolling stock is solved in the article. The main parameters of lubricators being considered in the article are compressed air supply, the geometry of a spray nozzle and the boundary thickness of a lubricant layer applied to the friction surface where there is no creep of a lubricant under the action of gravity. A structural model of application and retention of a lubricant on a friction surface has been proposed. A mathematical model to calculate main parameters of aerosol lubricators has been developed. The model establishes the connection between the geometry of lubricated friction surfaces, physico-chemical properties of lubricants and the diameter of nozzle aperture and the compressed air supply. The example of calculation of the boundary thickness of a lubricant layer applied to the friction surface under the condition of the absence of its creeping under the action of gravity has been presented in the article. The article presents the results of experimental studies the process of aerosol application of a lubricant to the friction surface.

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Koplin, Christof, Sherif Ahmed Abdel-Wahed, Raimund Jaeger, and Matthias Scherge. "The Transition from Static to Dynamic Boundary Friction of a Lubricated Spreading and a Non-Spreading Adhesive Contact by Macroscopic Oscillatory Tribometry." Lubricants 7, no. 1 (January 9, 2019): 6. http://dx.doi.org/10.3390/lubricants7010006.

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Lubricated poly(ether ether ketone) (PEEK) and polyamide (PA46)–steel tribosystems were investigated. They show a complex but systematic transition behavior from static to boundary friction, to dynamic friction or to mixed-lubrication. Nonstandard macroscopic oscillatory tribometry as well as gliding experiments were carried out. A previous study showed that the surface and interfacial energies of PEEK, lubricant and steel can indicate trends in the tribological behavior. In the current study, these findings are confirmed for PA46 and a wider range of lubricants. It was shown that a reversal of the order of the work of spreading of two lubricants by switching from PEEK to PA46 as polymer component in the tribological system also resulted in a reversal of the coefficient of friction (COF) at low gliding velocities for these systems. The adhesion threshold of PA46 with the non-spreading lubricants water, glycerine, a water–glycerine mixture, ethylene glycol and poly-1-decene decreased with increasing solving tendency of the lubricants in contrast to the previous results for spreading lubricants for PEEK. Furthermore, the onset of forced wetting was studied for lubricants with different surface and interfacial energies and viscosities η. In general, a 1/η dependency was observed for the velocity which marks the onset of forced wetting. This agrees with theoretical models.

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Dissertations / Theses on the topic "Boundary lubricants"

1

Poon, Chin Yim. "The influence of surface topography on sliding friction in boundary lubrication." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/11870.

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Cen, Hui. "Effect of water on the performance of lubricants and related tribochemistry in boundary lubricated steel/steel contacts." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/5434/.

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The objective of the overall project is to assess the effect of water on the performance of lubricants and related tribochemistry in boundary lubricated steel/steel contacts. The effect of water on the bulk properties of the lubricant, the tribological performance of lubricants and the mechanism of tribofilm formulation are the focus of this project. The tribological performance of different lubricants is evaluated by a ball-on-disc test rig as well as a micropitting rig under boundary lubrication and with different levels of humidity. Selected post test samples are analysed to study the reactions occurring during the test and the composition of the tribofilm. The surface analysis techniques used are Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The results of this thesis show that water can change the bulk properties (viscosity and TAN) of some lubricants in specific conditions dependent on the water level in the lubricants. The increase of relative humidity always increases wear of the components no matter whether under pure sliding or rolling-sliding conditions, but addition of water in the oil before the tribological test will not always increase wear. It is also observed from XPS results that there is a direct relationship between the oxygen concentration as oxide on the contact surfaces, the layer thickness on the wear scar of post test ball/roller and relative humidity. Also, it is revealed from the results that not only physical parameters but also chemistry must be considered to evaluate the micropitting behaviour, which is found by XPS analysis to be related to the chain length of the phosphate as well as the oxygen concentration as oxide on the wear scar of the surfaces.

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McGregor, Peter Stanley. "Modelling the Effect of Suspended Bodies on Cavitation Bubbles near a Ridgid Boundary using a Boundary Integral Approach." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15822/.

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Cavitation is the spontaneous vaporisation of a liquid to its gaseous state due to the local absolute pressure falling to the liquid's vapour pressure (Douglas, Gasiorek et al. 1995). Cavitation is present in a wide range of mechanical systems ranging from ship screws to journal bearing. Generally, cavitation is unavoidable and may cause considerable damage and efficiency losses to these systems. This thesis considers hydraulic systems specifically, and uses a modified Greens equation to develop a boundary integral method to simulate the effect that suspended solid bodies have on a single cavitation bubble. Because of the limitations of accurately modelling cavitation bubbles beyond touchdown, results are only presented for cases up to touchdown. The aim of the model is to draw insight into the reasons there is a measurable change in cavitation erosion rate with increasing oil-in-water emulsion percentage. This principle was extended to include the effect that ingested particulates may have on cavitation in hydraulic machinery. Two particular situations are modelled; the first consists of stationary rigid particles in varying proximity to a cavitation bubble near a rigid boundary. The second case is similar; however the suspended particle is allowed to move under the influence of the pressure differential caused by the expanding/contracting cavitation bubble. Numerous characteristics of the domain are considered, including domain pressures and fluid field motion, and individual boundary surface characteristics. The conclusion of the thesis is that solid bodies, either stationary or moving, have little effect on the cavity from an energy perspective. Regardless of size or density, all energy transferred from the cavity to the solid body is returned indicating that there is no net change. As this energy is ultimately responsible for the peak pressure experienced by the domain (and hence responsible for eroding the rigid boundary) as the cavity rebounds, it then serves that a cavity with a solid body will rebound at the same pressure as a cavity without a suspended body present. If this is coupled with the observation that the cavity centroid at touchdown is largely unaffected by the presence of a suspension, then it would appear that the bubble near a solid would rebound at a very similar position as a cavity without a solid. Consequently, the damage potential of a cavity is unaffected by a suspension. However, there is one point of contention as the profile of the re-entrant jet of the cavity is altered by the presence of a suspension. As energy is radiated away from the cavity during penetration, it is possible that the shape of the jet may alter the rate that energy is radiated away during penetration. However, this requires further research to be definitive.

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4

McGregor, Peter Stanley. "Modelling the effect of suspended bodies on cavitation bubbles near a rigid boundary using a boundary integral approach." Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/15822/1/Peter_McGregor_Thesis.pdf.

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Cavitation is the spontaneous vaporisation of a liquid to its gaseous state due to the local absolute pressure falling to the liquid's vapour pressure (Douglas, Gasiorek et al. 1995). Cavitation is present in a wide range of mechanical systems ranging from ship screws to journal bearing. Generally, cavitation is unavoidable and may cause considerable damage and efficiency losses to these systems. This thesis considers hydraulic systems specifically, and uses a modified Greens equation to develop a boundary integral method to simulate the effect that suspended solid bodies have on a single cavitation bubble. Because of the limitations of accurately modelling cavitation bubbles beyond touchdown, results are only presented for cases up to touchdown. The aim of the model is to draw insight into the reasons there is a measurable change in cavitation erosion rate with increasing oil-in-water emulsion percentage. This principle was extended to include the effect that ingested particulates may have on cavitation in hydraulic machinery. Two particular situations are modelled; the first consists of stationary rigid particles in varying proximity to a cavitation bubble near a rigid boundary. The second case is similar; however the suspended particle is allowed to move under the influence of the pressure differential caused by the expanding/contracting cavitation bubble. Numerous characteristics of the domain are considered, including domain pressures and fluid field motion, and individual boundary surface characteristics. The conclusion of the thesis is that solid bodies, either stationary or moving, have little effect on the cavity from an energy perspective. Regardless of size or density, all energy transferred from the cavity to the solid body is returned indicating that there is no net change. As this energy is ultimately responsible for the peak pressure experienced by the domain (and hence responsible for eroding the rigid boundary) as the cavity rebounds, it then serves that a cavity with a solid body will rebound at the same pressure as a cavity without a suspended body present. If this is coupled with the observation that the cavity centroid at touchdown is largely unaffected by the presence of a suspension, then it would appear that the bubble near a solid would rebound at a very similar position as a cavity without a solid. Consequently, the damage potential of a cavity is unaffected by a suspension. However, there is one point of contention as the profile of the re-entrant jet of the cavity is altered by the presence of a suspension. As energy is radiated away from the cavity during penetration, it is possible that the shape of the jet may alter the rate that energy is radiated away during penetration. However, this requires further research to be definitive.

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5

Trajano, Marinalva Ferreira. "Estudo tribol?gico de biolubrificantes com adi??o de nanopart?culas de ?xidos (zinco e cobre)." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15722.

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Made available in DSpace on 2014-12-17T14:58:23Z (GMT). No. of bitstreams: 1 MarinalvaFT_DISSERT.pdf: 2645446 bytes, checksum: d4a95fdf4bdc8c40f2876e653a2bb39f (MD5) Previous issue date: 2013-08-02
Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field
Atualmente, os ?leos vegetais tem sido base de estudo para biolubrificantes que se adequem ?s novas normas ambientais. Em um mundo cheio de recursos naturais finitos, os ?leos minerais, provenientes do petr?leo, trazem consequ?ncias ao meio ambiente devido sua baixa biodegradabilidade e toxicidade. Tamb?m deve-se considerar, os ?leos sint?ticos possuem um alto custo. O objetivo deste trabalho ? obter um biolubrificante aditivado com nanopart?culas de ?xido (ZnO e CuO) para uma melhor resist?ncia ao atrito e desgaste, que seja n?o t?xico ao meio ambiente e possua melhor ader?ncia em regime de lubrifica??o limite. Efetuou-se a s?ntese de biolubrificantes (soja e girassol) por rea??o de epoxida??o. Em seguida fizeram-se an?lises f?sico-qu?micas no biolubrificante para caracterizar os ?leos sintetizados, tais como; densidade, acidez, ?ndice de iodo, viscosidade, ?ndice de viscosidade. Posteriormente os mesmos foram aditivados com nanopart?culas. O desempenho tribol?gico foi avaliado pelo equipamento HFRR (High Frequency Reciprocating Rig), que consiste num ensaio de desgaste do tipo esfera-plano. A caracteriza??o do desgaste foi realizada atrav?s de an?lises de MEV/EDS. Os resultados demostraram que os biolubrificantes podem ser sintetizados por rea??o de epoxida??o, com boa convers?o. Do ponto de vista tribol?gico, os ?leos epoxidados puros s?o mais eficazes que os aditivados com nanopart?culas de ?xido, apresentaram menores coeficientes de atritos e melhor percentual de forma??o de filme neste estudo. Por?m, por serem ambientalmente corretos, os biolubrificantes ganham import?ncia relevante no meio tribol?gico

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Silvestro, Michael. "Analysis of boundary lubricant films using Raman spectroscopy." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39771.

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Манько, Наталія Миколаївна, Наталья Николаевна Манько, and Nataliia Mykolaivna Manko. "Stick-slip mode of boundary friction." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33545.

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The study of the boundary friction processes that develop in nanosized tribosystems has drawn active interest of many researchers. One of the perspective directions is the investigation of the friction of atomically smooth solid surfaces in the presence of an ultrathin film of a homogeneous lubricant between them. The interest is partially due to the applied significance of these systems, as they are used in increasing frequency to design precise devices and instruments. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33545

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Manko, N. N., and I. A. Lyashenko. "Stochastic Oscillations at Stick-Slip Motion in the Boundary Friction Regime." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35148.

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In this paper, the further development of the synergetic model describing the ultrathin lubricant film state clamped between two atomically smooth solid surfaces operating under boundary friction mode has been done based on the Lorentz model for the approximation of a viscoelastic medium. In all cases, the phase portraits have been built. It has been found that the friction surfaces' temperature increasing leads to the growth of stochasticity in the investigated system. In the phase plane the stochastic oscillation mode can be described as a strange attractor. Also, the behavior of two different types of tribosystems were described using current model. The first was the system with the unidirectional shear of the surfaces and, and the second was the system under an alternating external effect. Obtained results agree qualitatively with known experimental data. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35148

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Zhao, Ping. "Three-dimensional boundary element and experimental analysis of lubricant ceramic surface ring cracks in rolling contact." Thesis, Bournemouth University, 2006. http://eprints.bournemouth.ac.uk/10552/.

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Surface defects such as ring cracks are located on silicon nitride ceramic rolling elements.The random nature of ring crack position creates difficulties in predicting rolling contact fatigue (RCF) life. The influence of the lubricant, contact pressure and crack geometry on the RCF mechanism is difficult to determine due to the variable nature of RCF life when the crack location is not defined. In this study, rolling contact fatigue was tested using a novel experimental technique. The test ceramic ball specimen with identified surface ring cracks was precisely located in the contact path. The rolling contact fatigue tests were conducted using a modified four-ball machine in a hybrid ceramic/steel combination with five different types of lubricating mediums at various contact pressures. Detailed analysis of damage progression was carried out to study the mechanisms of fatigue failure. A boundary element analysis was used to determine the stress intensity factors around the crack front and stress distributions on the surface in the presence of the surface crack. The RCF tests of silicon nitride balls with surface ring cracks showed that fatigue life was strongly influenced by load/contact stress, crack size,lubricant and material type. Ring crack spalling failure is not only influenced by sub-surface fatigue crack propagation but also strongly influenced by secondary surface cracks. The formation of the secondary surface cracks is a key factor which dominates spalling of rolling contact fatigue. Modelling work showed that the crack length was an important parameter.Increasing the crack length for given crack radius resulted in higher tensile surface stresses ahead of the original ring crack and also gave higher absolute K11 values. In addition, the crack gap and crack face friction had a significant effect on the formation of secondary surface cracks and fatigue crack propagation behaviour. Increasing the crack face friction decreased both the surface tensile stress and absolute magnitude of K11. Numerical calculation results were consistent with the experimental observations.

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Súkeník, Juraj. "Vliv mazivostních přísad na snižování opotřebení třecích povrchů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229251.

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Lubricants additives are inseparable component of modern high-tech lubricants. Viscosity index improvers additives play uncoverable role in a branch of boundary lubrication. They are designed to ensure sufficient oil film thickness in low speeds of frictional surfaces motion. This thesis deal with effect of specific viscosity index improvers additives on boundary lubrication film formation in elliptical contact. The purpose of this work is also checking the effect of concentration changing these additives on lubricantion film thickness formation.

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Books on the topic "Boundary lubricants"

1

Gates, Richard Stephen. Boundary lubrication of silicon nitride. Gaithersburg, MD: U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology, 1995.

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Jones, W. R. Enhancement of perfluoropolyether boundary lubrication performance. [Washington, DC]: National Aeronautics and Space Administration, 1996.

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R, Jones W., and United States. National Aeronautics and Space Administration., eds. Enhancement of perfluoropolyether boundary lubrication performance. [Washington, D.C.]: National Aeronautics and Space Administration, 1995.

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A, Shogrin Bradley, Jones William R, and United States. National Aeronautics and Space Administration., eds. Spectroscopic analysis of perfluoropolyether lubricant degradation during boundary lubrication. Washington, DC: National Aeronautics and Space Administration, 1997.

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E, El-Bayoumy Lotfi, United States. National Aeronautics and Space Administration., and United States. Army Aviation Research and Technology Activity., eds. The Role of thermal and lubricant boundary layers in the transient thermal analysis of spur gears. [Washington, DC]: National Aeronautics and Space Administration, 1989.

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A rolling element tribometer for the study of liquid lubricants in vacuum. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1996.

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Evaluation of PS 212 coatings under boundary lubrication conditions with an ester-based oil to 300⁰C. [Washington, DC]: National Aeronautics and Space Administration, 1995.

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Spectroscopic analysis of perfluoropolyether lubricant degradation during boundary lubrication. Washington, DC: National Aeronautics and Space Administration, 1997.

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Book chapters on the topic "Boundary lubricants"

1

Persson, Bo N. T. "Boundary Lubrication." In Encyclopedia of Lubricants and Lubrication, 192–208. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-22647-2_78.

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Bush, Brian, Carlo Carraro, and Roya Maboudian. "Chemical Vapor Deposition Processes for Boundary Lubricants." In Encyclopedia of Tribology, 370–73. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_239.

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Müser, Martin H., and Martin Aichele. "Nature of Instabilities in Boundary Lubricants and Their Effect on Kinetic Friction." In ACS Symposium Series, 55–68. Washington, DC: American Chemical Society, 2004. http://dx.doi.org/10.1021/bk-2004-0882.ch005.

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Everson, M. P., A. K. Gangopadhyay, R. C. Jaklevic, D. Scholl, and Weidian Shen. "Effects of Boundary Lubricants and Metallic Oxides in Steel-Steel Tribological Junctions Studied with the Atomic Force Microscope." In Forces in Scanning Probe Methods, 425–30. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0049-6_37.

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Timsit, R. S. "Effect of Surface Reactivity on Tribological Properties of a Boundary Lubricant." In Fundamentals of Friction: Macroscopic and Microscopic Processes, 287–98. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2811-7_15.

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Schirru, Michele. "Viscosity Measurements at an Aluminium-Oil Boundary." In Development of an Ultrasonic Sensing Technique to Measure Lubricant Viscosity in Engine Journal Bearing In-Situ, 89–100. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53408-4_6.

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Demydov, Dmytro, Atanu Adhvaryu, Philip McCluskey, and Ajay P. Malshe. "Advanced Lubricant Additives of Dialkyldithiophosphate (DDP)-Functionalized Molybdenum Sulfide Nanoparticles and Their Tribological Performance for Boundary Lubrication." In ACS Symposium Series, 137–63. Washington, DC: American Chemical Society, 2010. http://dx.doi.org/10.1021/bk-2010-1045.ch008.

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"Boundary Lubricants." In Encyclopedia of Tribology, 259. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_100131.

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Mate, C. Mathew, and Robert W. Carpick. "Lubrication." In Tribology on the Small Scale, 259–300. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780199609802.003.0009.

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For situations where high friction is not explicitly needed, lubricants are used to reduce friction and wear to acceptable levels. Lubricants function mainly by introducing a layer of solid or liquid material with low shear strength between two sliding surfaces. This chapter covers the basic regimes of lubrication: hydrostatic, hydrodynamic, elastohydrodynamic, mixed, and boundary. Viscosity is the most important physical parameter describing a lubricant, and it is thoroughly discussed in this chapter. Slippage of lubricants and other liquids against solid surfaces is also discussed. The chapter also discusses the basic mechanisms and types of bearings that provide hydrodynamic and elastohydrodynamic lubrication.

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"Boundary Lubrication and Lubricants." In Principles and Applications to Tribology, 655–88. The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118403020.ch10.

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Conference papers on the topic "Boundary lubricants"

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Adhvaryu, Atanu, Brajendra K. Sharma, and Sevim Z. Erhan. "Process Development and Tribochemical Evaluation of Seed Oil Based Antiwear/Antifriction Additive." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63380.

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Antiwear / antifriction additives enhance the ability of lubricant to withstand mechanical stresses of interacting surfaces under boundary lubrication conditions. Majority of the lubricants and additives currently used are petroleum based that are toxic to environment, making it increasingly difficult for safe and easy disposal. There has been an increasing demand for “green” lubricants and lubricant additives in recent years due to concerns about lubricants lost to the environment and increasingly strict government regulations controlling their use.

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Shaub, Harold, John Pandosh, Anne Searle, and Stan Sprague. "Mechanism Studies with Special Boundary Lubricant Chemistry." In 1995 SAE International Fall Fuels and Lubricants Meeting and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1995. http://dx.doi.org/10.4271/952475.

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Lorenzo-Martin, C., O. O. Ajayi, JungKyu Lee, and Andreas A. Polycarpou. "Frictional Behavior of Boundary Lubricated Contacts: Effect of Tribochemical Surface Films." In ASME/STLE 2009 International Joint Tribology Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ijtc2009-15098.

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The friction characteristics of lubricated contacts are usually determined by the shearing of three interfacial structural elements; namely lubricant fluid film, tribochemical reaction films and the near-surface materials. The shear behavior of the fluid film components of lubrication can be adequately described by either the hydrodynamic, or elastohydrodynamic theories and calculations. The shear behavior of the near surface materials can also be approximated by contact mechanics. However, due to the complexity and lack of adequate information, description and analysis of the tribochemical film contributions to frictional behavior is more challenging. In this study we present evaluation of the friction behavior of a lubricated contact as a function of tribological test duration, as the tribochemical surface films were being formed. Tests were conducted with two different formulated lubricants, in addition to an unformulated PAO basestock lubricant. One of the formulated lubricants consists of PAO synthetic basestock with 2.5% each of ZDDP and MoDTC additives. The other formulated lubricant is a fully formulated commercial gear oil with similar viscosity. During the friction tests in a fully flooded reciprocating sliding roller-on-flat contact configuration, the friction coefficient decreased exponentially as the tribochemical films were formed; highlighting the impact of boundary films on friction. In the test with the basestock fluid, the friction remained constant for the duration of the test; although an oxide layer was formed. Nanoindentation hardness and modulus measurements were conducted on two of the tribochemical films to measure their mechanical properties and the consequent impact on measured friction during testing.

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Erdemir, Ali, and George R. Fenske. "Clean and Cost-effective Dry Boundary Lubricants for Aluminum Forming." In International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1998. http://dx.doi.org/10.4271/980453.

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Shaub, Hal, John Pandosh, Anne Searle, Stan Sprague, and Martin Treuhaft. "Engine Durability, Emissions and Fuel Economy Studies with Special Boundary Lubricant Chemistry." In International Fuels & Lubricants Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1994. http://dx.doi.org/10.4271/941983.

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Duong, CongTruyen, Jae-Hoon Lee, SangSoo Lee, and Seonghun Park. "Effect of Albumin Concentrations on Frictional Coefficients of Cobalt-Chromium Femoral Head From Atomic Force Microscopy." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19065.

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Atomic Force Microscopy (AFM) has been widely used to measure frictional properties of diverse materials at the microscopic level [1, 2]. Furthermore, there has been the general agreement that albumin plays an important role as an effective lubricant in the frictional behavior of hip implant materials. Through hip simulator, it has been reported that either boundary or mixed lubrication occurs when bovine serum albumin was used as a lubricant [3, 4]. When lubricants contained proteins of albumin or globulin, the frictional properties of the rubbing surfaces were affected by the adsorption of these constituents on the bearing surfaces of the prostheses [4]. Through macroscopic pin-on-disk measurements, another study in the literature has reported the importance of albumin as an effective lubricant for reducing friction and wear of hip implant materials [5]. Although microscopic AFM measurements are very effective for exploring boundary lubrication of diverse lubricants on joint implants, because the frictional coefficients of bearing surfaces in the joint implants can be measured without being affected by the surface roughness of bearing materials, the effect of boundary lubrications of bovine serum albumin (BSA) on hip implant materials has not been well identified. Therefore, the objective of the present study is to investigate the role of BSA as a boundary lubricant in the lubrication of cobalt-chromium (CoCr) femoral head ten years after total hip arthroplasty (THA) by measuring its frictional coefficients with AFM techniques.

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Cabrera, Cruz R., Héctor J. Franco, and Nobis Torres. "Study of Boundary Lubrication Oil Performance Using the Oil Activity Surface, EDAX and SEM Data." In International Fuels & Lubricants Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1993. http://dx.doi.org/10.4271/932788.

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Dubrovsky, R., and A. Titov. "Friction and Wear in the Presence of Fullerene Contained Lubricants at Boundary Conditions." In STLE/ASME 2003 International Joint Tribology Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/2003-trib-0264.

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This work describes application of fullerenes as additives for liquid lubricants such as motor oils. Experiments include dynamic tracking of friction coefficient and weight measurements of samples before and after experiments. Friction coefficient measurements have been done on computer-controlled wear-friction testing machine, which has been developed at Surface Engineering Laboratory in NJIT. For the proposed series of experiments, this machine employs conforming disc-on-ring arrangement of rubbing bodies at boundary lubrication; sample couple is steel AISI 4340 and bronze SAE 40; nominal contact pressure ranges from 1.9 MPa to 3.7 MPa with sliding speed of 0.61 m/s. Tested lubricants were prepared on the basis of super duty motor oil SAE 10 by adding one weight percent of additives: pure C60, mixture of C60 and C70 and graphite powder. Performance comparison of fullerene contained lubricants with pure oil and oil modified by graphite powder showed that although there is no any clear difference in friction coefficient value for tested lubricants, fullerene contained lubricants decrease wear rate of rubbing bodies.

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Adam, Abdullah, Naoki Inukai, Yoshiyuki Kidoguchi, Kei Miwa, and Seiji Miyashiro. "A Study on Droplets Evaporation at Diesel Spray Boundary during Ignition Delay Period." In JSAE/SAE International Fuels & Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2007. http://dx.doi.org/10.4271/2007-01-1893.

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Ovaert, T. C., H. S. Cheng, and M. C. Shen. "Temperature Effects on Friction and Elevated Temperature Behavior of Base Oil-Additive Combinations Under Boundary Lubricated Conditions." In International Fuels & Lubricants Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1991. http://dx.doi.org/10.4271/912395.

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