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Статті в журналах з теми "Antiwear film"
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Schwarz, Udo D. "Tracking antiwear film formation." Science 348, no. 6230 (April 2, 2015): 40–41. http://dx.doi.org/10.1126/science.aaa3276.
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Topolovec-Miklozic, Ksenija, T. Reg Forbus, and Hugh A. Spikes. "Film thickness and roughness of ZDDP antiwear films." Tribology Letters 26, no. 2 (January 9, 2007): 161–71. http://dx.doi.org/10.1007/s11249-006-9189-2.
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Sun, Zhiyong, and Xianhua Cheng. "Self-Assembly and Tribological Properties of Carbon Nanotubes Film on Silicon Substrates." Nano 10, no. 07 (October 2015): 1550098. http://dx.doi.org/10.1142/s1793292015500988.
Повний текст джерелаАнотація:
Carbon nanotubes (CNTs) film was prepared on silicon ( Si ) substrate with a 3-aminopropyltriethoxysilane (APTES) film as the interlayer in a multistep self-assembly process. The formation and microstructure of the CNTs film were characterized by using scanning electron microscopy (SEM), water contact angles (WCAs) and X-ray photoelectron spectrometry (XPS). Tribological properties were evaluated with a UMT-2MT reciprocating friction tester. Results show that the CNTs were successfully assembled on Si substrates by chemical bonding between functional groups. CNTs film exhibited excellent friction reduction, high load-bearing capacity and antiwear ability. The friction coefficient was reduced drastically from 0.7 to 0.16, with markedly prolonged antiwear lifetime compared to bare Si substrates or APTES film. These superior tribological properties are attributable to the remarkable mechanical properties of CNTs and strong bond properties with the APTES film. CNTs film is thus expected to find wider application as high-performance lubricating film in micro/nanoelectromechanical systems (M/NEMS) in future.
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Chen, Huan, Jing Li, Tianhui Ren, Lei Zheng, and Yidong Zhao. "Tribological behaviors of three novel imidazoline-type thiadiazole derivatives as multifunctional lubricant additives in biodegradable lithium grease." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 226, no. 8 (March 7, 2012): 668–77. http://dx.doi.org/10.1177/1350650112439808.
Повний текст джерелаАнотація:
Three novel imidazoline-type thiadiazole derivatives are prepared and used as antiwear and extreme-pressure additives in biodegradable lithium grease, and their tribological performances are evaluated using a four-ball tester. Tribological tests show that all derivatives are effective in reducing wear, especially at lower additive concentrations. Oleic acid-imidazoline-type thiadiazole derivative is a preferred additive to reduce wear. For the friction-reducing property of base grease, improvements after using these derivatives are not remarkable. On the other hand, these derivatives are also effective extreme-pressure additives. In order to understand the friction process further, chemical composition of tribofilms under antiwear/extreme-pressure regime is analyzed by X-ray absorption near edge structure spectroscopy, and thermal films are also considered for comparison. Thermal films formed by these imidazoline-type thiadiazole derivatives consist of adsorbed organic sulfide and ferrous sulfide. Sulfur presents several chemical valences in the antiwear regime, and tribofilms generated by stearic acid and lauric acid-imidazoline-type thiadiazole derivatives at 1.0 wt% are composed of ferrous disulfide, ferrous sulfide and ferrous sulfate. The appearance of disulfide suggests that the interfacial temperature between the upper ball and three lower balls under antiwear conditions is considerably low. Composition of extreme-pressure films generated by oleic acid and lauric acid-imidazoline-type thiadiazole derivatives is only ferrous sulfide, and the extreme-pressure film for stearic acid imidazoline-type thiadiazole derivative is a mixture of ferrous sulfide, ferrous sulfate, and adsorbed organic sulfide.
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Wan, Ping Nan, Jie Yang, and You Quan Zhong. "Tribological Property of some Triazine Derivatives in Hydrogenated Oil." Advanced Materials Research 1008-1009 (August 2014): 323–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.323.
Повний текст джерелаАнотація:
Two ashless triazine derivatives, 2,4-bi-amido-6-(O,O′-di-i-octhyl dithiophosphate)- 1,3,5 - triazine were synthesized. Their tribological properties as lubricating oil additives compared with ZDDP in hydrogenated oil were evaluated using a four-ball tester. The results show that these triazine derivatives possess extreme pressure capacity, and they can improve antiwear and friction-reducing performance of base stock than that of ZDDP. Their tribological performance is corresponding to the amide. The elements chemical states of the worn surface were estimated through X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The results show that a protective film containing sulphide, phosphate and some organic nitrogen compounds was formed on the worn surface during the lubrication process, and the film possesses extreme pressure and antiwear properties.
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Gao, X.-M., M. Hu, J.-Y. Sun, L.-J. Weng, F. Zhou, and W.-M. Liu. "Copper films deposited by arc ion plating at low temperatures exhibiting excellent antiwear behaviour." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 225, no. 11 (September 19, 2011): 1121–29. http://dx.doi.org/10.1177/1350650111413638.
Повний текст джерелаАнотація:
Cu films were prepared by arc ion plating (AIP) at low temperature ( Ts) and investigated by X-ray diffraction, field emission scanning electron microscope atomic force microscopy, transmission electron microscope, etc. It is found that low Ts (≤ 221 K) can refine the crystallite size of the Cu films and leads to compact and smooth surface structure. Further decreasing Ts to 135 K makes the inter-grain gaps turn bigger. The wear behaviours of the Cu films in vacuum were characterized using a ball-on-disk tribometer. The results show that the Cu films deposited at the Ts range of 135–221 K have better wear resistance, and the wear rates are two to three orders lower than that of the film deposited at room temperature. The compact and dense arrangement of nanoscale crystallites significantly contributes to the improved film–substrate adhesion and so the excellent antiwear behaviour.
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Wang, Xiao Li, Bin Shi Xu, Yi Xu, Qian Liu, and Pei Jing Shi. "The Nano-Effect of Nanometer Lubricating Material in Equipment Maintenance." Advanced Materials Research 154-155 (October 2010): 716–20. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.716.
Повний текст джерелаАнотація:
The nano-effects of nano-Cu lubricating material in equipment maintenance were researched from reducing friction effect, antiwear effect and repairing effect by comparing tribology properties of nano-Cu lubricating material with micro-Cu material. The nano-effect mechanism was discussed. The results indicated that the reducing friction effect and the antiwear effect can make the friction coefficient and the worn track width of lubricant reduce to 16% and 40% respectively. The repairing effect can make the nano-Cu lubricating material forms repairing film on wore surface. That of all is decided by the characteristics of nano-Cu lubricating material.
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Boichenko, Sergii, Kazimierz Lejda, Anna Iakovlieva, Hubert Kuszewski, and Oksana Vovk. "EXPERIMENTAL STUDY ON ANTIWEAR PROPERTIES FOR BLENDS OF JET FUEL WITH BIO-COMPONENTS DERIVED FROM RAPESEED OIL." Transactions of the Institute of Aviation 245, no. 4 (December 31, 2016): 352–65. http://dx.doi.org/10.5604/05096669.1230970.
Повний текст джерелаАнотація:
Antiwear properties of jet fuel, two kinds of biocomponents derived from rapeseed oil and their mixtures were investigated experimentally. Antiwear properties were estimated by the value of the scuffing load and the limiting load of scuffing applied to the friction pair working in a fuel medium. Biocomponents, mainly rapeseed oil FAME and rapeseed oil FAME modified via vacuum distillation were used during the study. It is found that lubricity of biocomponents is significantly higher comparing to conventional jet fuel. It is explained by the chemical composition of FAME: highly polarity of molecules stipulate their good adsorption at the surface of friction pair. High viscosity of biocomponents due to chemical structure positively influence on their lubricity. Adding biocomponents into jet fuel results in strengthening boundary film and thus improves antiwear properties of fuel blends. It is determined that FAME modified via vacuum distillation possess better lubricating ability comparing to standard FAME derived from rapeseed oil. Correlation between viscosity and lubricity of fuel is shown
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Chanchikov, Vasiliy Aleksandrovich, Ivan Nikolaevich Guzhvenko, Nina Vladimirovna Pryamuhina, Mariya Sergeevna Pryamukhina, and Oleg Petrovich Kovalev. "Experimental studying tribological characteristics of lubricating oils with layered friction modifiers and their application in marine technology." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2022, no. 1 (February 28, 2022): 22–34. http://dx.doi.org/10.24143/2073-1574-2022-1-22-34.
Повний текст джерелаАнотація:
The paper presents the results of studying the lubricity of several lubricating compositions, two of which contain an antiwear additive based on a layered friction modifier - molybdenum diselenide. Oil MC-20, which does not contain functional antiwear additives, is used as a base lubricating medium and an object of comparison. Two variants for combining an antiwear additive with this oil differ in the process of initial preparation of the additive before adding it to the base lubricating oil by rotary pulsation grinding and stirring. Antiwear tests are arranged in the form of a consistent tribological rating of the given types of lubricating media at various operating time of the friction path of the test samples. The test tool is a rotary-type friction machine of an original design. There are analyzed the differences in the antiwear test methodology and the advantages of the proposed scheme over the analogous one, which is relevant for GOST R 51860-2002. Among the results of the tribological study carried out, topographic patterns of wear of test specimens, the dependence of the wear rate of tribological surfaces on contact pressures, and the dependence of the wear scar diameter on the amount of specimen wear are given. The antiwear additive has been found to contain a layered friction modifier of selenium dichalcogenide (molybdenum diselenide) type, it improves the lubricating film on friction surfaces and reduces their wear compared to the use of nonadditive oil MS-20. The wear degree of a stationary ball-shaped specimen when testing a lubricating medium with the antiwear additive is reduced by 66-85% compared to a base lubricating oil without additives. The diameter of the wear spot on a stationary specimen under these test conditions is reduced by 28-67%, which proves the effectiveness of preliminary preparation by rotary-pulsation mixing of a lubricant composition with a solid suspended base even with a relatively short preparation time.
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Xiong, Li Ping, Zhong Yi He, Jun Xiao Wang, Liang Qian, and Sheng Han. "Tribological Property of a Triazine Derivative in Rapeseed Oil." Advanced Materials Research 284-286 (July 2011): 293–96. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.293.
Повний текст джерелаАнотація:
2-propylamino-4,6-(O,O’-dibuthyldithiophosphate)-s-1,3,5-triazine(DPOB)was synthesized and it’s tribological behavior as lubricant in rapeseed oil (RSO) were evaluated using a four-ball tester. The lubrication mechanism was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results indicate that the compound possess excellent load-carrying capacity and antiwear ability, and has some friction-reducing property only under the low load condition. Based on the results of XPS and SEM analysis, it can be seen that tribochemical reaction occurred between the synthesized compounds and metal surfaces during the sliding process, to form a complex film which has excellent load-carrying capacity and antiwear ability.
Дисертації з теми "Antiwear film"
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Taylor, Lisa Jane. "The film-forming and wear-reducing properties of antiwear additives." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246920.
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Hoshino, Koji. "Film forming and friction properties of sulphur-free antiwear additives zinc dialkylphosphates (ZDPs)." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6811.
Повний текст джерелаАнотація:
ZDPs (zinc dialkylphosphates) are sulphur-free analogues of the conventional antiwear additives ZDDPs (zinc dialkyldithiophosphates). Recently, the application of ZDPs in practical use has been investigated as an alternative of ZDDPs. The key benefit of ZDPs is that they do not contain sulphur which may damage some catalysts in after-treatment exhaust systems. Utilizing ZDPs instead of ZDDPs contributes to decrease in sulphur content in engine oils. In addition, ZDP-formulated oils show better base number retention than ZDDPs, which could contribute to prolongation of engine oil life. This is because ZDPs do not generate sulphuric acid in their decomposition process, while ZDDPs generate sulphuric acid which consumes detergents. However there is still little known about the mechanism of action of ZDPs as antiwear additives. Therefore, the purpose of this study is to clarify how ZDP antiwear additives work by investigating the film forming and friction properties of ZDPs. The main technique employed was MTM-SLIM (mini traction machine - spacer layer interferometry). This machine can measure friction properties under various rubbing conditions and monitor film formation by additives during rubbing tests. This study has shown that ZDPs form stable reaction films by rubbing, which protect metal surfaces from wear. This is fundamentally similar to the mechanism for antiwear performance of ZDDPs. However, some differences between ZDPs and ZDDPs are seen in their filmforming properties, which may affect their antiwear performances. For example, the filmforming rates of ZDPs are slower than those of ZDDPs at the initial stage. Stabilized films formed by ZDPs are thinner than films formed by ZDDPs. By contrast, ZDPs show similar friction properties to ZDDPs. In the boundary and mixed lubrication regions, there is no noticeable difference in friction between stabilized films formed by ZDPs and ZDDPs. In addition, these properties are largely affected by various factors such as rubbing conditions, concentrations, and alkyl structures of the additives. For example, ZDPs having linear alkyl chains show slower film formation and lower boundary friction than ZDPs having branched alkyl chains. Moreover, other additives such as dispersants and detergents largely affect the properties of ZDPs. Generally, highly polar additives appear to retard the film formation of ZDPs. The mechanisms for the above features are also discussed in this thesis.
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Zhang, Jie. "Influence of succinimide dispersants on film formation, friction and antiwear properties of zinc dialkyl dithiophosphate." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9196.
Повний текст джерелаАнотація:
ZDDP (zinc dialkyldithiophosphate) is arguably the most successful antiwear additive ever employed in crankcase engine lubricants. It was originally used as an antioxidant and shortly afterwards recognized for its antiwear and extreme pressure properties. Unfortunately, another critical additive polyisobutylsuccinimide-polyamine (PIBSA-PAM), which is used as a dispersant in engine oils, is known to be antagonistic to ZDDP in terms of film formation, friction and wear. The mechanisms of this antagonism have been widely studied, but they are still not well understood. Furthermore, in order to protect engine exhaust catalysts from sulphated ash, phosphorus and sulphur (SAPS) and extend drain intervals of engine lubricants, a progressive reduction in ZDDP quantity but a growth in the use of PIBSA-PAM is required. The aim of this study is to explore the mechanisms and practical effects of the antagonism between ZDDP and PIBSA-PAM. Of particular interest is the impact on performance of the ratio of ZDDP to PIBSA-PAM, as measured by P:N ratio. Since ZDDP is a very effective antiwear additive, it produces only very low or "mild" rates of wear. To study this requires a new way to measure mild wear behaviour of formulated oils. Several techniques have been applied in this study to investigate the film formation, friction and wear properties of ZDDP- and/or PIBSA-PAM-containing oils. These include a new mild wear testing method, which is tested and developed using a range of different types of additives. It is found that the ratio of P:N plays a strong role in determining tribofilm formation and friction of ZDDP/PIBSA-PAM blends. However it plays a much weaker role in determining wear behaviour. It is found that some PIBSA-PAMs have considerable friction-reducing properties in their own right. The results suggest that PIBSA-PAM may interfere with the behaviour of ZDDP in several ways: by forming a ZDDP/ PIBSA-PAM complex at the metal surfaces to reduce the local activity of ZDDP; by PIBSA-PAM partially removing the ZDDP film; possibly also by PIBSA-PAM blocking ZDDP from metal surfaces. The newly-developed wear testing method can be used conveniently and effectively to study mild wear properties not just of ZDDP but of a wide range of other additives.
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Sharma, Subhash Chandra. "Wear reducing additives for lubricants containing solid contaminants." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20661/.
Повний текст джерелаАнотація:
Machines operating in dusty environments, such as mining and civil works, are prone to premature failure, leading to production losses. To address this problem, this research project examines the interaction between solid contaminants and the bearing micro-geometry, in lubricated surface contacts. In particular, it seeks to identify anti-wear additives that are effective in reducing wear under abrasive conditions, making machine elements more dirt tolerant.
In general, the influence of antiwear additive is so small that it is difficult to isolate it. Manufactures often make claims about their antiwear products, which are difficult to verify. Hence, there is a need to characterising the antiwear additives available with a well-defined parameter, making it easier for consumers to compare the efficacy of various additives, and be able to select the most suitable additive for a given environment.
Effect of micro-geometry parameters such as radial clearance, out-of-roughness and surface roughness was examined and a Film Shape Factor (FSF) – also termed gamma ratio – has been proposed for ensuring adequate separation of journal bearings operating in hydrodynamic lubrication regime, where the out-of-roundness values are higher than the surface roughness values.
In this research, an experimental study has been conducted on journal bearings, to examine the influence of five antiwear additives on the bearing wear and micro-geometry. The test additives were provided by the industry partner without revealing their chemical identity or composition; however, these included some of the most commonly used antiwear additives. The tests were performed under three conditions: pure base oil, base oil containing contaminants, and base oil containing contaminants treated with five different additives.
The experiments were aimed at choosing one wear measuring technique that evaluates the performance of an individual additive reliably, and based on this technique the additives were characterised. To achieve these objectives, a multi-wear parameter approach (MWPA) was developed, which employed three main wear measurement methodologies, i.e. weight loss, micro-geometry and particle counts –to examine the effect of the antiwear additives. Minimum oil film thickness was also measured to study the lubrication status in the bearing contacts. The MWPA helped in comparing different wear measuring methods, and in selecting the most reliable one. This approach also helped in developing short duration wear tests, thereby saving time, while still getting reliable results without repeating these.
Wear experiments were performed on seven sets of bronze bearings and steel sleeve shafts. The test contaminant was 16 micron Aluminium oxide Al2O3 powder mixed in oil with 4% concentration by weight. These solid contaminants were treated with five different antiwear additives to study their influence on the bearings. Bearings were operated such that the minimum oil film thickness in the bearing was equal to the size of the contaminants. These tests were run for a constant sliding distance of 7536m.
The results showed that most of the wear measuring techniques do not suit heavily contaminated test conditions. However, the out-of-roundness technique proved to be the most reliable and practical. Based on this technique a methodology was developed which gave a wear characteristic number (N). A unique value of N can be derived for each additive, thereby ranking the additives for their efficacy.
The finding of this research provides a better understanding of the methodologies used for measuring wear in journal bearings subjected to dusty environments, and examines the efficacy of each one of these. The wear characteristic number (N) can be used by manufacturers with support from international standards organisations, so that the users can confidently choose the most appropriate antiwear additive for their application.
Machines operating in a dusty environment, such as mining industry and civil works are prone to premature failure with subsequent production losses. In response to this problem, this research project examines the interaction between solid contaminant particles and the lubricant film micro-geometry in lubricated surface contacts. In particular, it seeks to identify lubricant anti-wear additives, which are effective in reducing wear under abrasive conditions and thus making machine elements more dirt tolerant.
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Gauvin, Mélanie. "Approche analytique in situ du mécanisme anti-usure des phosphates de zinc." Ecully, Ecole centrale de Lyon, 2008. http://www.theses.fr/2008ECDL0021.
Повний текст джерелаАнотація:
L’élaboration d'additifs de lubrification respectueux de l'environnement nécessite la compréhension du mode d'action d'additifs anti-usure tel que le dithiophosphate de zinc (ZDDP). Le ZDDP a la. Propriété remarquable de former un film mince résistant à l'usure，appelé tribofilm, à l’interface d'un contact en régime de lubrification limite. Les pressions locales de l'ordre de plusieurs giga Pascals (GPa) dans un contact tribologique en régime de lubrification limite sont potentiellement capables de transformer la structure atomique et les propriétés des matériaux à l’interface. Au cours de ces travaux, nous avons mis en évidence les transformations structurales in situ de composés modèles du ZDDP, sous l'effet de hautes pressions hydrostatiques allant jusqu'à 20 GPa. Nous avons choisi de modéliser le ZDDP par les phosphates de zinc (ZP) suite à l' étude de différents lubrifiants composés de Zn3(P04)2, Zn2P207, et Zn(P03)2 dispersés dans une huile de poly-alfa-oléfine utilisés lors de tests tribologiques en régime de lubrification limite, à température ambiante. La formation d'un tribofilm amorphe formé à partir de Zn3(P04)2 a été observée. Ses propriétés mécaniques et topographiques sont comparables à celles du tribofilm de ZDDP. En revanche, la formation d'un tribofilm à l'interface est négligeable dans le cas de Zn2P207 et Zn(P03)2. Les transformations structurales des unités P04 dans différents ZP sous haute pression ，jusqu'à 20 GPa ont été mises en évidence par spectroscopie Raman in situ. Le degré de polymérisation des chaînes de phosphate est conservé sous pression, menant à la conc1usion que la pression n'est pas responsable de la formation de longue chaînes de phosphate dans le tribofilm de ZDDP. Entre 0. 1 MPa et 4 GPa，les spectres Raman de α-Zn3 (P04 )2 montrent une transition de phase de la structure cristalline initiale sous l'effet de la pression. Au-delà de 4 GPa, la signature vibrationnelle de l' échantillon suggère une perte progressive de l'ordre à longue portée sous pression. A la décompression, la structure obtenue est similaire à la forme amorphe du composé Zn3(P04)2. La structure locale sous pression des atomes de Zn dans α-Zn3(P04 )2 a été étudiée par spectroscopies EXAFS et XANES in situ au seuil K du zinc. Entre 0,1 MPa et 3,5 GPa, l’ordre à longue portée autour du zinc disparaît et la distance moyenne Zn-O augmente de 0,046 + 0,005 A. Le nombre de coordination du zinc n’augmente pas significativement sous une pression maximale de 7 GPa. Le désordre structural est acquis irréversiblement. Enfin, un tribomètre alternatif combiné avec un spectromètre Raman nous a permis d’observer in situ les trnasformations structurales du composé Zn3(PO4)2 sous l’effet de contraintes tribologiques. Des tructures similaires à celles formées sous haute pression hydrostatique ont été mises en évidence dans le contact tribologique. La formation d'un tribofilm amorphe composé de Zn3(PO4)2 est observée à l'interfaceEco-friendly lubricant additives are of primary environmental and economical importance. Their design rely on our understanding of anti-wear additives such as the zinc dialkyldithiophosphate (ZDDP). ZDDP has the remarkable property of forming a thin protective coating against wear， called ZDDP-tribofilm ，at the interface of a boundary lubricated contact. However, detailed reactional pathwaγs leading to the ZDDP tribofilm formation and mechanisms responsible for wear inhibition are still unsolved. High local pressures in the range of several giga pascals in a boundary lubricated contact are likely to modify the atomic structure and macroscopic properties of materials at this interface. Our work focuses on an in situ analysis of structural modifications of ZDDP-like model compounds when exposed to high hydrostatic pressures, up to 20 GPa. We chose to model the ZDDP additive by zinc phosphate compounds (ZP) after performing tribological tests under boundary lubrication conditions using colloidal Zn3 (P04)2, ，Zn2P207 and Zn(P03 )2 compounds mixed to a poly-alpha-olefin oil, at ambient temperature formation of a tribofilm is observed at the interface for Zn3(P04)2 while it is negligible for Zn2P207 and Zn(PO3)2 materials. Mechanical and topographical properties of the amorphous film formed from Zn3(P04)z at the interface, show some similarities with ZDDP tribofilm. In situ micro-Raman spectroscopy was used to probe P04 tetrahedra structural modifications in ZP compounds of different phosphate chain lengths, up to 20 GPa. Pressure had no effect on PO4 tetrahedra polymerization in tested materials and cannot account for the formation of long-chain phosphates found in the ZDDP-tribofilm. Between 0. 1 MPa. And 4 GPa, α -Zn3(P04 )2 Raman spectra undergo important modifications which were attributed to a phase transition of the initial crystalline structure. Above 4 GPa，Zn3(P04 )2 Raman spectra show a progressive loss of the long-rang order in the sample. The structure recovered after decompression is similar to an amorphous Zn3(P04 )2 compound. Local environment of Zn atoms in α Zn3(PO4)2 was investigated under' high static pressure by in situ Zn-K edge EXAFS and XANES spectroscopies. Crystalline order around Zn atoms was found to vanish down to the second sphere of coordination and the mean Zn-O bond length is increased by 0. 046 +0. 005. A when pressure increases from 0. 1 MPa to 3. 5 GPa. The coordination number around Zn atoms does not change significantly at a maximal pressure of 7 GPa. The disordered local structure of zinc atoms observed at high pressure is conserve a decompression. Finally, a reciprocating tribometer combined with in situ micro-Raman spectroscopy was used to probe α-Zn3(P04)2 structural transformations occurring under combined shear and pressure constrains at ambient temperature. Tribolocically constrained Zn3(P04)2 structures were found to be identical to high pressure phases formed in static high pressure experiment and led to the formation of an amourphous zinc orthophosphate tribofilm
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Heffernan, John Vincent Thomas. "A fundamental surface study of phosphorus based antiwear films on iron." Thesis, University of Southampton, 1994. https://eprints.soton.ac.uk/365531/.
Повний текст джерела
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Tseng, Ying-Chieh, and 曾纓婕. "Enhancing The Antiwear And Lubrication Characteristics Of The Composite Oxide Films On Aluminium Alloy By Use Of Anodizing Oxidation And Micro-Arc Oxidation Method." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/15336521145009293989.
Повний текст джерелаАнотація:
碩士龍華科技大學
機械工程系碩士班
102
Taiwan’s bicycle industry has been renowned as a leading role around the world. However, the bicycle industry in Taiwan has to progress in the research and design ability in order to face the global competition. Among the bicycle parts, shock absorbers are the main components. They are made of aluminum alloys under the treatment of anodizing oxidation. Unfortunately, the surface characteristics of the treatment are unable to match the demands from bicycle industry. As a consequence, we prepare anodized composite and micro-arc composite films on Aluminum alloy by means of adding various solid lubricant particles (PTFE and MoS2) and surfactant in the electrolyte. The results indicate that the composite oxide films added with solid lubricant particles have lower average roughness and friction coefficient. In particular, the micro-arc composite film added with MoS2 has the best result of roughness, 1.10μm and friction coefficient, 0.496. Along the same lines, adding surfactant SDS and 1g/L PTFE added in the electrolyte for the micro-arc oxidation film is also effective to reduce the friction coefficient and wear loss of the films to 0.451 and 2.4mg/3000 rpm.
Книги з теми "Antiwear film"
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Dall’asta, Monica, and Jane M. Gaines. Prologue. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252039683.003.0002.
Повний текст джерелаАнотація:
This prologue examines overarching issues about women's film history, feminism, and the researching and writing of film history. Foregrounding historiographic problems, it explores the researching and writing about women “in” and “as” “history” in the cinema century by focusing on the critical-historical approach, which deals with the problem of “the history of history” —the approach used to expose the never-neutral amnesias of traditional historiography and to counter its claim to objectivity with the inevitability of its “fictions.” The chapter discusses the concept of becoming historical others and highlights the impossibility of history's history by drawing on the case of Elvira Giallanella, an Italian director and producer never mentioned in previous accounts of Italian silent cinema but who suddenly made her way into feminist historiography after a 35mm print of her 1919 antiwar film Umanità was discovered in 2007.
Частини книг з теми "Antiwear film"
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Dorgham, A., A. Neville, and A. Morina. "Tribochemistry and Morphology of P-Based Antiwear Films." In Microtechnology and MEMS, 159–214. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99897-8_6.
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Monnet, Agnieszka Soltysik. "Is There Such a Thing as an Antiwar Film?" In A Companion to the War Film, 404–21. Hoboken, NJ: John Wiley & Sons, Inc, 2016. http://dx.doi.org/10.1002/9781118337653.ch24.
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"Tribochemical Nature of Antiwear Films." In Tribochemistry of Lubricating Oils, 121–60. Elsevier, 2003. http://dx.doi.org/10.1016/s0167-8922(03)80019-6.
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Goedde, Petra. "The Politics of Peace." In The Politics of Peace, 189–220. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780195370836.003.0008.
Повний текст джерелаАнотація:
The last chapter examines the migration of a politics of peace from the margins to the centers of political power. As leading antinuclear and peace advocates became increasingly marginalized by the student and antiwar movements, their efforts were beginning to bear fruit in the arena of international politics. They were helped by a popular groundswell of sentiment that saw the arms race and the political ideology of nuclear deterrence as increasingly absurd. Absurdist writers, filmmakers, and philosophers of the 1950s and 1960s creatively underscored the absurdist nature of Cold War politics through works such as Joseph Heller’s Catch-22, Stanley Kubrick’s science fiction film Dr. Strangelove, and the fictional secret government Report from Iron Mountain. Together, they helped pave the way for political leaders, including Nixon in the United States, and Willy Brandt in West Germany, to develop a more pragmatic politics of peace.
Тези доповідей конференцій з теми "Antiwear film"
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Taylor, Lisa, Hugh Spikes, and Hugo Camenzind. "Film-Forming Properties of Zinc-Based and Ashless Antiwear Additives." In CEC/SAE Spring Fuels & Lubricants Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2000. http://dx.doi.org/10.4271/2000-01-2030.
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Smeeth, Matthew, Clive Hamer, and Hugh A. Spikes. "A Study of Antiwear Additive Film Build Up Using the MTM (Mini-Traction Machine)." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44249.
Повний текст джерелаАнотація:
The measurement of lubricant film thickness under elastohydrodynamic (EHL) contact conditions is well established and a variety of experimental techniques have been used, the most accurate and widely used of which is optical interferometry. This lends itself particularly well to the study of the all-important mixed and boundary regimes, since the films are of the same order of magnitude as the wavelength of light. The vast majority of these studies have been made under pure rolling conditions, since the necessary optical coatings preclude the use of high sliding speeds within the critical thin fluid film regime. These conditions are however precisely those required to activate ZDDPs and other antiwear additives, making accurate ‘in situ’ optical studies of additive film build-up difficult. A modification to the existing MTM (mini-traction machine) has allowed steel on steel contacts to be run under high sliding speed conditions, thereby allowing antiwear additive reactions to occur. By optically measuring the film thickness of these reaction films as they form, in tandem with friction measurements, a full picture of both friction and reaction film build-up can be made. Using a novel LED (light emitting diode) light source and accurate calibration procedures, the film thickness of the whole contact area can be measured down to a few nanometres. This paper presents a study of the behaviour of standard additive combinations under realistic operating conditions and describes the rig in detail.
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Wong, Victor W., and Kai Liao. "Sensitivity of Engine-Component Wear to Lubricant-Additive and Contact Conditions Using an Antiwear Film Formation Model." In STLE/ASME 2008 International Joint Tribology Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ijtc2008-71219.
Повний текст джерелаАнотація:
Traditional engine wear models link wear rates to detailed material and contact conditions. Effects of lubricant and additive characteristics are often described by and lumped in empirical parameters such as wear coefficients. With increased environmental concern that lubricant and additives impact emissions and exhaust treatment catalysts, there is increasing interest in optimizing the lubricant and additive combination while providing adequate protection against engine wear. While the mechanisms of anti-wear film formation have been studied in great detail, engineering models of component wear incorporating lubricant chemistry are just beginning to emerge. These models build on the understanding of anti-wear film mechanisms developed and published over the years on the one hand, and on classical wear models for rough surfaces on the other. One such model has been applied to study the sensitivity of the following effects on component wear: Kinetics of ZDDP, which vary according to type and formulation, surface characteristics, contact loads and temperatures, as well as the replenishment and depletion rates of lubricant-additive to the surface-lubricant interfaces. The calculations are done for several engine components under real-world operating conditions.
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Bec, S., K. Demmou, and J. L. Loubet. "Mechanical Properties of ZDTP Tribofilms Measured by Nanoindentation: Strain Rate and Temperature Effects." In STLE/ASME 2008 International Joint Tribology Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ijtc2008-71145.
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This study aims to contribute to better understand the antiwear action of zinc dialkyldithiophosphate (ZDTP) additives used in car engine lubrication. The antiwear action of ZDTP is associated to the formation of a protective tribofilm onto the rubbing surface. On a mechanical point of view, the efficiency of ZDTP tribofilms results from equilibrium between film formation and wear rates, associated with appropriate rheological properties. In this work, the mechanical properties of a ZDTP tribofilm have been measured by nanoindentation in different test conditions in order to investigate the effect of temperature and strain rate. A Nanoindenter XP® entirely set into a climatic chamber was used to perform the nanoindentation tests. For all tests, an increase of the elastic modulus was observed from a threshold contact pressure value. This effect is similar to the anvil effect observed on polymers: in confined geometry, the elastic modulus increases versus hydrostatic pressure. For the tribofilm, in the studied range, this effect is enhanced at high temperature and low strain rate. Furthermore, when the temperature increases, a change in the rheological behavior of the tribofilm is observed. Up to about 50°C, the tribofilm exhibits viscoplastic behavior — the hardness increases versus strain rate — and above 50°C, the hardness decreases versus strain rate (“shear thinning-like” behavior).
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Narita, K., and M. Priest. "Friction Characteristics and Topography of Tribofilms From Anti-Wear Additives Applied to Metal V-Belt Type CVT Fluids." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44204.
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This study has investigated the metal-meal friction properties and the topography of tribochemical films derived from antiwear additives for application to metal-V-belt pushing type continuously variable transmission fluids (B-CVTFs). The influence of metal-metal tribological properties of various kinds of anti-wear additives were evaluated using a ball on plate tribometer, enabling lubricant film formation to be monitored during a reciprocating sliding test. In addition, contact mode atomic force microscope (AFM) was used to characterize the nature of the tribofilms at the namometre scale. For zinc-dithiophosphate (ZnDTPs), significant differences were observed in the friction coefficients and the topographic images between secondary and aryl type ZnDTP. The films derived from secondary type exhibit large solid pads, 5–30μm in length elongated in the sliding direction while the aryl type forms films in streaks on the ridges, with 8% higher friction coefficient than the secondary ZnDTP. Notably, the combination of over-based calcium sulphonate and hydrogen phosphite demonstrated a synergism with 8% higher friction coefficient and more stable film formation than the individual cases, providing a positive outcome for a BCVTF. Tribofilm species produced by a chemical reaction between hydrogen phosphite and over-based calcium sulphonate were densely deposited on the rubbing tracks, exhibiting rougher surfaces than those observed in the individual cases, consequently with a higher friction coefficient. These results suggest that the friction properties between metal-metal contacting surfaces strongly depend on the morphology of tribofilms derived from lubricant additives.
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Norton, P. R., Gavin Pereira, Yue-Rong Li, Andreas Lachenwitzer, Masoud Kasrai, Todd Simpson, Dmitry Shakhvorostov, et al. "Nanoscale Studies of the Role of ZDDPs in the Wear Protection in the Automobile Engine." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44156.
Повний текст джерелаАнотація:
The improvement of fuel consumption is an important driving force for research and development in the automobile industry in order to minimize greenhouse gas emissions as well as improving fuel economy. Aluminum alloys are a class of alternative materials that are being used to replace cast iron in motor components due to the concomitant weight savings which result in improved fuel efficiency, and cost savings. Our research focuses on these alternative Al-based alloys as well as traditional steel interfaces, and the protective films that form on the surfaces. Currently the zinc dialkyl-dithiophosphates (ZDDPs) have been used as engine oil additives for over 60 years. They are important chemically-active additives, known for their antioxidant and antiwear characteristics. ZDDPs are known to form a protective film (tribofilms) at rubbed surfaces, typically on iron containing metals surfaces commonly used in the automotive industry; however ZDDPs and the products formed are not well suited for the environment as they can readily poison the catalytic converters and their efficacy on Al-Si alloys is not well established.
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Roby, S. H., E. S. Yamaguchi, M. M. Francisco, and S. G. Ruelas. "Electrical Contact Resistance Measurements. Part I. Temperature Effects on Antiwear Film Formation by Secondary, Primary, and Aryl Zinc Dithiophosphates in Fully Formulated Engine Oil." In 2003 JSAE/SAE International Spring Fuels and Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2003. http://dx.doi.org/10.4271/2003-01-1971.
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Guan, Wenchao, Gang Ke, Changyu Tang, and Yifeng Liu. "Study on Lubrication Properties of Carboxymethyl Cellulose as a Novel Additive in Water-Based Stock." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64250.
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This paper reports cellulose derivative—carboxymethyl cellulose (CMC) as a novel additive in a water-based stock (water content above 95 wt.%). Cellulose is one of the richest renewable resources on earth and has many peculiar qualities. Several cellulose derivatives such as CMC can easily dissolve in water and form stable thin film on the surface of metal. Several apparatus involving four-ball machine were used to investigate lubrication properties of the based stock containing CMC. The worn surfaces were observed with a scanning electron microscope. As the results, the anti-wear ability of the base stock is effectively increased by addition of a small amount (0.7 wt.%) of CMC. The additive with peculiar molecular structure contributes to abate the adhesion and scuffing of frictional pair effectively, hence improves the antiwear ability of the base stock. Thus CMC provides a potential application in the field of water-based stock lubrication.
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Jiaa, Chi L., and Youmin Liu. "The Depletion and Retention Characteristics of PFPE Lubricants and X1P on Magnetic Media." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0214.
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Abstract The depletion and retention characteristics of magnetic thin film rigid disks coated with PFPE lubricants and X1P additive were investigated in this study. The tribological performance was evaluated by a drag test with a waffle head sliding against the disk that was designed to mechanically wear out the lubricant layer. An IR beam was aligned on the test track to directly measure the amount of PFPE lubricants and X1P left on the media surfaces for determining the depletion and retention characteristics of the lubricants. The test results show that under ambient and hot/wet (60°C/80%RH) conditions the media coated with AM3001 have higher retention ratio on the test track than those coated with ZDOL2000. After the head sliding for 100 hours, about 40% AM3001 still remains on the test track, while almost no ZDOL2000 left. However, the X1P was observed to strongly anchor on the surface and not wear out as PFPE lubricants did. The retention characteristics of X1P are independent of lube combination, either AM or ZDOL lubricants. The data indicate that more than 60% of the original X1P remains on the test track under all test conditions. The remaining X1P is quite stable and does not decrease as the drag test time increases during the latter test stage. It is demonstrated that X1P exhibits a good antiwear property and excellent retention performance.
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Furey, Michael J., Czeslaw Kajdas, Gustavo J. Molina, and Brian Vick. "A Critical Assessment of Tribopolymerization as an Antiwear Mechanism." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63308.
Повний текст джерелаАнотація:
By tribopolymerization, we mean the planned, intentional, and continuous formation of protective polymeric films on tribological surfaces by the use of minor concentrations of selected monomers capable of forming polymer films “in situ” by polycondensation or addition polymerization. The approach involves the design of molecules which will form polymeric surface films in critical regions of boundary lubrication. The concept has been shown to be effective in reducing wear with ceramics as well as metals in both liquid and vapor phase applications. The purpose of this paper is threefold, namely: 1. To review our key fundamental research on the topic of tribopolymerization, including more recent views based on measurements of triboelectron emission. 2. To summarize the applications of this concept to a variety of industrial problems, including the use of the compounds in fuels as well as in areas in which environmental issues are important. 3. To briefly outline future plans for fundamental research on tribopolymerization, including theoretical and experimental studies to examine the roles of surface temperature, triboelectron emission, and catalysis on surface polymerization.