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Xiaobo Wang - One of the best experts on this subject based on the ideXlab platform.

  • tribological characteristics of bisphenol s bis diphenyl phosphate as a high performance Antiwear Additive in lubricating greases at elevated temperature
    Lubrication Science, 2016
    Co-Authors: Lili Zhu, Gaiqing Zhao, Xiaobo Wang
    Abstract:

    Bisphenol S bis(diphenyl phosphate) (BSDP) was synthesised and characterised, and its tribological behaviours as Additives in polyurea grease and lithium complex grease were evaluated for steel/steel contact at 200 °C. The results indicated that BSDP could dramatically reduce the friction and wear of sliding pairs in the base grease of polyurea, and the tribological performances of BSDP in polyurea grease were significantly superior to the normally used molybdenum disulfide-based Additive package. Furthermore, BSDP in polyurea grease has better tribological behaviour than that in lithium complex grease at a constant load of 100 N. X-ray photoelectron spectroscopy analysis indicated that boundary lubrication films composed of Fe(OH)O, Fe2O3, Fe3O4 and FePO4 compounds containing the P–O bonds and nitride compounds were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance. Copyright © 2016 John Wiley & Sons, Ltd.

  • tribological characteristics of bisphenol af bis diphenyl phosphate as an Antiwear Additive in polyalkylene glycol and polyurea grease for significantly improved lubrication
    Applied Surface Science, 2016
    Co-Authors: Lili Zhu, Gaiqing Zhao, Xiaobo Wang
    Abstract:

    Abstract A new Antiwear Additive of Bisphenol AF bis(diphenyl phosphate) (BAFDP) was synthesized and characterized. The tribological behaviors of the Additive for polyalkylene glycol (PAG) and polyurea grease (PG) application in steel/steel contacts were evaluated on an Optimol SRV-IV oscillating reciprocating friction and wear tester at elevated temperature. The results revealed that BAFDP could drastically reduce friction and wear of sliding pairs in both PAG and also in PG at 100 °C. The tribological properties of BAFDP are superior to the normally used zinc dialkyldithiophosphate-based Additive package (ZDDP) in PAG and PG. Moreover, BAFDP as Additive for PAG and PG displays relatively significant tribological properties in temperature-ramp tests by performing well at 50–300 °C, indicating the excellent high temperature friction reduction and anti-wear capacity of BAFDP. XPS results showed that boundary lubrication films composed of Fe(OH)O, Fe 3 O 4 , FePO 4 , FeF 2 , FeF 3 , compounds containing the P O bonds, nitrogen oxide, and so forth, were formed on the worn surface, which contributed to excellent friction reduction and Antiwear performance.

  • tribological properties of castor oil tris diphenyl phosphate as a high performance Antiwear Additive in lubricating greases for steel steel contacts at elevated temperature
    RSC Advances, 2014
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Qin Zhao, Ming Zhang, Weimin Li, Xiaobo Wang
    Abstract:

    Castor oil tris(diphenyl phosphate) (CODP) was synthesized using an environmentally friendly and renewable resource – castor oil, and its tribological properties were evaluated in lithium 12-hydroxystearate greases (LHG) and lithium complex greases (LCG) at 150 °C. The tribological behaviors of the Additive for LHG and LCG application in steel/steel contacts were evaluated on an Optimol SRV-IV oscillating reciprocating friction and wear tester as well as on a MS-10J four-ball tester. The worn steel surface was analyzed by a JSM-5600LV scanning electron microscope and a PHI-5702 multifunctional X-ray photoelectron spectrometer. The results indicated that CODP as the Additive could effectively reduce the friction and wear of sliding pairs in the two base greases. The tribological performances were also better than the traditional used zinc dialkyldithiophosphate (ZDDP) based Additive package in LHG and also in LCG. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4 and compounds containing P–O bonds were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

  • tribological properties of alkylphenyl diphosphates as high performance Antiwear Additive in lithium complex grease and polyurea grease for steel steel contacts at elevated temperature
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Qin Zhao, Xiaobo Wang
    Abstract:

    The alkylphenyl diphosphates pentaerythritol tetrakis(diphenyl phosphate) (PDP) and trimethylolpropane tris(diphenyl phosphate) (TDP) were evaluated as the Antiwear Additives in lithium complex grease and polyurea grease at 200 °C. The results indicated that both Additives may effectively reduce the sliding friction and wear as compared to the base greases. The tribological performances were generally better than the normally used molybdenum disulfide (MoS2)-based Additive package in lithium complex grease and also in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4, and compounds containing the P–O bonds were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

  • tribological properties of naphthyl phenyl diphosphates as Antiwear Additive in polyalkylene glycol and polyurea grease for steel steel contacts at elevated temperature
    RSC Advances, 2014
    Co-Authors: Xinhu Wu, Xiaobo Wang
    Abstract:

    Naphthyl phenyl diphosphates: 1-naphthyl diphenyl phosphate (NDP) and 1,5-dihydroxynaphthalene bis(diphenyl phosphate) (DDP) were evaluated as the Antiwear Additives in polyalkylene glycol and polyurea grease at 200 °C. Results showed that they could effectively reduce the friction and wear of sliding pairs compared with the cases without these Additives. Furthermore, the tribological properties of NDP and DDP were generally better than the normally used tricresyl phosphate (TCP) in PAG and molybdenum disulfide (MoS2) in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4 were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

Anne Neville - One of the best experts on this subject based on the ideXlab platform.

  • On the Transient Decomposition and Reaction Kinetics of Zinc Dialkyldithiophosphate.
    ACS applied materials & interfaces, 2018
    Co-Authors: Abdel Dorgham, Ardian Morina, Abdullah Azam, Anne Neville
    Abstract:

    Despite the ubiquitous use of the zinc dialkyldithiophosphate (ZDDP) as an Antiwear Additive, no complete information is yet available on its exact decomposition reactions and kinetics to form triboreactive protective films on contacting surfaces. This hinders the replacement of ZDDP with more environmentally friendly Additives of similar Antiwear capabilities. Using a multitechnique approach, this study shows that before the formation of a phosphate-rich protective film, the decomposition of ZDDP proceeds by forming intermediate zinc sulfide and sulfate species, which can be mechanically mixed with the iron oxides on the rubbing steel surfaces. The mixed sulfur-oxide layer can play different vital roles including binding the subsequently formed phosphate layers with the metal surface. These layers consist mainly of zinc thiophosphate of initially short chains, which are formed due to the excess concentration of metal oxide on the surface. As the concentration of the oxide decreases in the subsequent layers, the short chains start to polymerize into longer ones. The polymerization process follows first-order reaction kinetics with two distinctive phases. The first one is a fast transient burst phase near the steel surface, whereas the second phase dominates the formation process of the layers away from the substrate and is characterized by slow kinetics. The findings of this study provide new insights into the decomposition mechanisms of the currently most widely used Antiwear Additive and open future opportunities to find green alternatives with similar superior Antiwear properties.

  • ZDDP and its interactions with an organic Antiwear Additive on both aluminium–silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • zddp and its interactions with an organic Antiwear Additive on both aluminium silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • the lubrication of both aluminium silicon and model silicon surfaces with calcium sulphonate and an organic Antiwear Additive
    Tribology International, 2013
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The lubrication of a line contact between an aluminium–silicon cylinder liner and a chromium steel piston ring, which operates under mild wear boundary lubricated conditions, has been investigated. The lubricant was synthetic six centistokes poly alpha olefin based, into which calcium sulphonate and an organic Antiwear Additive were blended. Calcium carbonate based tribofilms were generated exclusively on silicon grains within the aluminium alloy. Replication of the contact conditions using chromium steel pin on silicon plate generated larger scale tribofilms, which comprised small, interlinked pads; these were chemically identical to those on the aluminium–silicon alloy. The thickness and elastic modulus of the tribofilm generated on the silicon substrate were determined and the results compared against previous findings by the current author.

  • Effect of Friction Modifiers and Antiwear Additives on the Tribological Performance of a Hydrogenated DLC Coating
    Journal of Tribology-Transactions of the Asme, 2010
    Co-Authors: Ardian Morina, T. Haque, Anne Neville
    Abstract:

    There has been a lot of attention on the effect of lubricant Additives on the friction at carbon coated surfaces. But only few papers have addressed the effect of Additives on the durability of some diamondlike carbon DLC coatings. This paper presents a systematic study assessing the Additive/Additive and Additive/surface interactions, and their influences on the durability of a low hydrogen-containing (15 at. % hydrogen) metal-free DLC coating (a-C:15H). In this study, lubricating oils containing a zinc dithiophosphate (ZDDP) Antiwear Additive and/or organomolybdenum friction modifiers (moly dimer and moly trimer) were used. Tribological tests were carried out in a pin-on-plate tribometer under boundary lubrication conditions. To understand the effect of Additives, tribofilms formed on the wear tracks were analyzed using surface sensitive analytical techniques such as atomic force microscope, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. Results showed that the ZDDP formed a zinc phosphate containing an ultrathin Antiwear tribofilm, which offered excellent durability/wear protection to the a-C:15H coating. However, the Antiwear performance of this Additive was compromised when it was used with moly dimer or moly trimer. Surface analysis revealed that unlike steel surfaces, MoS(2) formed on the DLC surfaces had negligible influence on friction, while the low friction DLC wear debris had strong influence on friction. Abrasive wear was found to be the dominating wear mechanism in the cases when Additives showed poor wear protection on the a-C:15H coating. [DOI: 10.1115/1.4001650]

Ardian Morina - One of the best experts on this subject based on the ideXlab platform.

  • On the Transient Decomposition and Reaction Kinetics of Zinc Dialkyldithiophosphate.
    ACS applied materials & interfaces, 2018
    Co-Authors: Abdel Dorgham, Ardian Morina, Abdullah Azam, Anne Neville
    Abstract:

    Despite the ubiquitous use of the zinc dialkyldithiophosphate (ZDDP) as an Antiwear Additive, no complete information is yet available on its exact decomposition reactions and kinetics to form triboreactive protective films on contacting surfaces. This hinders the replacement of ZDDP with more environmentally friendly Additives of similar Antiwear capabilities. Using a multitechnique approach, this study shows that before the formation of a phosphate-rich protective film, the decomposition of ZDDP proceeds by forming intermediate zinc sulfide and sulfate species, which can be mechanically mixed with the iron oxides on the rubbing steel surfaces. The mixed sulfur-oxide layer can play different vital roles including binding the subsequently formed phosphate layers with the metal surface. These layers consist mainly of zinc thiophosphate of initially short chains, which are formed due to the excess concentration of metal oxide on the surface. As the concentration of the oxide decreases in the subsequent layers, the short chains start to polymerize into longer ones. The polymerization process follows first-order reaction kinetics with two distinctive phases. The first one is a fast transient burst phase near the steel surface, whereas the second phase dominates the formation process of the layers away from the substrate and is characterized by slow kinetics. The findings of this study provide new insights into the decomposition mechanisms of the currently most widely used Antiwear Additive and open future opportunities to find green alternatives with similar superior Antiwear properties.

  • ZDDP and its interactions with an organic Antiwear Additive on both aluminium–silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • zddp and its interactions with an organic Antiwear Additive on both aluminium silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • the lubrication of both aluminium silicon and model silicon surfaces with calcium sulphonate and an organic Antiwear Additive
    Tribology International, 2013
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The lubrication of a line contact between an aluminium–silicon cylinder liner and a chromium steel piston ring, which operates under mild wear boundary lubricated conditions, has been investigated. The lubricant was synthetic six centistokes poly alpha olefin based, into which calcium sulphonate and an organic Antiwear Additive were blended. Calcium carbonate based tribofilms were generated exclusively on silicon grains within the aluminium alloy. Replication of the contact conditions using chromium steel pin on silicon plate generated larger scale tribofilms, which comprised small, interlinked pads; these were chemically identical to those on the aluminium–silicon alloy. The thickness and elastic modulus of the tribofilm generated on the silicon substrate were determined and the results compared against previous findings by the current author.

  • Effect of Friction Modifiers and Antiwear Additives on the Tribological Performance of a Hydrogenated DLC Coating
    Journal of Tribology-Transactions of the Asme, 2010
    Co-Authors: Ardian Morina, T. Haque, Anne Neville
    Abstract:

    There has been a lot of attention on the effect of lubricant Additives on the friction at carbon coated surfaces. But only few papers have addressed the effect of Additives on the durability of some diamondlike carbon DLC coatings. This paper presents a systematic study assessing the Additive/Additive and Additive/surface interactions, and their influences on the durability of a low hydrogen-containing (15 at. % hydrogen) metal-free DLC coating (a-C:15H). In this study, lubricating oils containing a zinc dithiophosphate (ZDDP) Antiwear Additive and/or organomolybdenum friction modifiers (moly dimer and moly trimer) were used. Tribological tests were carried out in a pin-on-plate tribometer under boundary lubrication conditions. To understand the effect of Additives, tribofilms formed on the wear tracks were analyzed using surface sensitive analytical techniques such as atomic force microscope, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. Results showed that the ZDDP formed a zinc phosphate containing an ultrathin Antiwear tribofilm, which offered excellent durability/wear protection to the a-C:15H coating. However, the Antiwear performance of this Additive was compromised when it was used with moly dimer or moly trimer. Surface analysis revealed that unlike steel surfaces, MoS(2) formed on the DLC surfaces had negligible influence on friction, while the low friction DLC wear debris had strong influence on friction. Abrasive wear was found to be the dominating wear mechanism in the cases when Additives showed poor wear protection on the a-C:15H coating. [DOI: 10.1115/1.4001650]

Michael R. Sutton - One of the best experts on this subject based on the ideXlab platform.

  • ZDDP and its interactions with an organic Antiwear Additive on both aluminium–silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • zddp and its interactions with an organic Antiwear Additive on both aluminium silicon and model silicon surfaces
    Tribology International, 2014
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The boundary lubrication of an aluminium–silicon alloy using zinc dialkyldithiophosphate (ZDDP) or ZDDP and an organic Antiwear Additive (OAW) has been investigated. Contact conditions on silicon grains within the aluminium alloy were replicated using a model silicon surface. On either substrate, ZDDP tribofilms did not form readily and possessed poor lubricating characteristics, but the addition of the organic Additive improved film formation and wear performance. An increase in film thickness, surface coverage and mechanical properties of the ZDDP+OAW tribofilm was accredited with the wear improvement. The tribochemistry of worn aluminium–silicon and silicon surfaces was similar to ZDDP-lubricated ferrous substrates.

  • the lubrication of both aluminium silicon and model silicon surfaces with calcium sulphonate and an organic Antiwear Additive
    Tribology International, 2013
    Co-Authors: Michael Stephen Burkinshaw, Ardian Morina, Anne Neville, Michael R. Sutton
    Abstract:

    Abstract The lubrication of a line contact between an aluminium–silicon cylinder liner and a chromium steel piston ring, which operates under mild wear boundary lubricated conditions, has been investigated. The lubricant was synthetic six centistokes poly alpha olefin based, into which calcium sulphonate and an organic Antiwear Additive were blended. Calcium carbonate based tribofilms were generated exclusively on silicon grains within the aluminium alloy. Replication of the contact conditions using chromium steel pin on silicon plate generated larger scale tribofilms, which comprised small, interlinked pads; these were chemically identical to those on the aluminium–silicon alloy. The thickness and elastic modulus of the tribofilm generated on the silicon substrate were determined and the results compared against previous findings by the current author.

Sevim Z. Erhan - One of the best experts on this subject based on the ideXlab platform.

  • Antiwear Additive Derived from Soybean Oil and Boron Utilized in a Gear Oil Formulation
    Industrial & Engineering Chemistry Research, 2012
    Co-Authors: Brajendra K. Sharma, Kenneth M. Doll, Glenn L. Heise, Malgorzata Myslinska, Sevim Z. Erhan
    Abstract:

    The synthesis of lubricant Additives based on boron and epoxidized soybean oil are presented. These Additives are made from a simple patent pending method involving a ring-opening reaction of the epoxidized oil. A couple of these borates were tested in soybean oil, polyalpha olefin basestock, group III basestock, and hexadecane. An aromatic Additive was able to increase the oxidation onset of the basestocks by 14, 52, 48, and 49 °C, respectively, when used at 2% wt. The other Additive was shown to reduce the wear scar diameter in a friction test when used in soybean oil basestock, from 0.61 mm down to 0.41 mm. These Additives were also tested in a gear oil blend, and shown to reduce both wear and oxidation. They were also compatible with a popular Additive, Additive zinc dialkyl dithiophosphate.

  • Soybean Oil-Based Lubricants: A Search for Synergistic Antioxidants†
    Energy & Fuels, 2007
    Co-Authors: Brajendra K. Sharma, Joseph M. Perez, Sevim Z. Erhan
    Abstract:

    Vegetable oils can contribute toward the goal of energy independence and security due to their naturally renewable resource. They are promising candidates as base fluids for ecofriendly lubricants because of their excellent lubricity, biodegradability, good viscosity−temperature characteristics, and low evaporation loss. Their use, however, is restricted due to low thermo-oxidative stability and poor cold-flow behavior. This paper presents a systematic approach to improve their oxidation behavior by searching for a suitable Additive combination. The study of antioxidant/Antiwear Additive synergism was investigated on a set of four antioxidants and three Antiwear Additives in vegetable oils using pressure differential scanning calorimetry (PDSC) and a rotary bomb oxidation test (RBOT). The results indicate that dialkyldithiocarbamate antioxidant performed better than diphenylamine and hindered phenol. The zinc dialkyldithiocarbamate antioxidant showed excellent synergism with Antiwear Additive antimony dit...

  • Development and Tribochemical Evaluation of Biobased Antiwear Additive
    Tribology, 2005
    Co-Authors: Sevim Z. Erhan, Brajendra K. Sharma
    Abstract:

    Seed oils are renewable resources, environmentally friendly non toxic fluids, pose no work place health hazards and are readily biodegradable. The amphiphilic character of these oils makes them an excellent candidate as lubricants and as specialty chemicals. Industrial application of seed oils is limited due to poor thermo-oxidative stability, poor low temperature fluidity, and other tribochemical degrading processes that occur under severe conditions of temperature, pressure, shear stress, metal surface and environment. This work describes the development and tribochemical evaluation of seed oil based Antiwear Additive through chemical modification. The current process retains the seed oil structure, eliminates poly-unsaturation in the molecule, and adds polar functional groups that significantly improve adsorption on metal surfaces. These compounds also contribute to the formation of protective films through chemical reaction during the tribochemical process. Comparative tests with commercial products demonstrate its effectiveness.Copyright © 2005 by ASME