The influence of base oil polarity on the tribological performance of zinc dialkyl dithiophospate additives

Suarez, Aldara Naveira; Grahn, Mattias; Pasaribu, R.; Larsson, Roland

doi:10.1016/j.triboint.2010.07.016

Cited by 62 publications

(26 citation statements)

References 40 publications

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“…The water would increase the oil polarity. Higher oil polarity would limit the ZDDP‐additive molecule access to the surface and thus modify the reaction layer chemistry (phosphate chain length) and physical properties (wear and friction behaviour and hardness) . Increased corrosion and wear due to the presence of hydroxyl groups in the lubricant was reported by Tomala et al ., which is in agreement with expectations regarding low reaction layer performance in the presence of water …”

Section: Discussionmentioning

confidence: 99%

XPS analysis on the influence of water on the evolution of zinc dialkyldithiophosphate–derived reaction layer in lubricated rolling contacts

Nedelcu

Piras

Rossi

et al. 2012

Surface & Interface Analysis

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aThe presence of water in lubricating oil affects the performance of lubricated rolling contacts. This work particularly focuses on the role of water in altering the evolution of zinc dialkyldithiophosphate (ZDDP)-derived reaction layers. A series of tribological tests were carried out using a rolling four-ball machine. Different initial water amounts were added to 2 wt% ZDDP in poly-alpha-olefin (PAO). The reaction layer evolution and its chemical properties were studied using XPS and SEM. SEM analyses show that water seems to inhibit the growth of the ZDDP-derived reaction layer. XPS analyses reveal that the reaction layer undergoes a depolymerisation of the polyphosphate chain when water is present in lubricated contacts. Surface distress was observed in 2 wt% ZDDP in poly-alpha-olefin, whereas when water was mixed with pure base oil, the surface distress increased. Different mechanisms of the influence of water on the ZDDP-derived reaction layer evolution are discussed.

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Section: Discussionmentioning

confidence: 99%

XPS analysis on the influence of water on the evolution of zinc dialkyldithiophosphate–derived reaction layer in lubricated rolling contacts

Nedelcu

Piras

Rossi

et al. 2012

Surface & Interface Analysis

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“…The above finding is difficult to understand and explain as per general belief that the presence of polar component in lubricant adversely affects the tribological performance of ZDDP . In that context additised PP and PE grease would have shown similar or better results than lithium grease and increasing thickener content in lithium grease would have adverse effect on wear performance.…”

Section: Resultsmentioning

confidence: 92%

“…A. Naveira Suarez et al in a study with base oil of different polarity reported that the film formation and antiwear activity of ZDDP depends on the polarity of the components present in the lubricant. The non polar component present in the lubricant does not hinder the access of additive molecule to the surface whereas polar component due to its higher affinity competes with the additive molecule to adhere to the surface and therefore, restricts antiwear film formation by the additive molecules.…”

Section: Resultsmentioning

confidence: 99%

A study on tribological behaviours of ZDDP in polymer thickened lubricating greases

2015

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Zinc Dialkyl Dithiophosphate (ZDDP) is a well-known multifunctional additive for soap based lubricating greases. Polymers are being studied for their performance as lubricating grease thickeners and rheology modifiers. In this work the tribological study of ZDDP was carried out in polypropylene (PP), maleated polypropylene (mPP) and linear low density polyethylene (PE) thickened lubricating greases. Performance of lithium grease was taken as a reference. The tribological properties were evaluated using a four ball tester for EP properties and Optimol SRV-III machine for coefficient of friction. The mechanism of action of ZDDP in polymer greases was established through analysis of the worn surface of steel balls with scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDAX). The results show that the performance of ZDDP depends on the thickener system. The antiwear and EP property exhibited by ZDDP varies from polymer to polymer. Poor performance was observed with PP type thickener whereas performance in PE and lithium grease was comparable.

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“…The main reason is the difference in polarity between the matrix (the base oil) and the additive. 19,20 Creating long-term stable mixtures for consumers' application like in automotive lubricants involves complex chemistry 21 and is part of the corporate knowledge of oil and additive package producers. Related to ILs as additives, it is important that these blends are either thermodynamically stable (like solutions) or kinetically stable (like emulsions), or that the composition of the lubricant can be chosen in a way that its properties remain constant throughout the performed tests.…”

Section: Ils As Additivesaspects Of Polaritymentioning

confidence: 99%

“…It is well known that the introduction of anti‐wear additives into PAO base oil cannot be normally accomplished by simple mixing of two or more compounds together. The main reason is the difference in polarity between the matrix (the base oil) and the additive . Creating long‐term stable mixtures for consumers' application like in automotive lubricants involves complex chemistry and is part of the corporate knowledge of oil and additive package producers.…”

Section: Introductionmentioning

confidence: 99%

Miscibility and tribological investigations of ionic liquids in biodegradable esters

Kronberger

Pagano

Pejaković

et al. 2014

Lubrication Science

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The structural impact of ionic liquids was systematically investigated by assessing their behaviour as lubricant additives in two different biodegradable esters (refined rapeseed oil and synthetic ester). Cations were mainly based on derivatives of the tetraalkyl ammonium structure; the anions were alkyl sulfate, methyl sulfonate or bis(trifluoromethylsulfonyl)imide. Miscibility experiments showed that ultrasound treatment yielded the most stable emulsions. X‐ray fluorescence was employed to determine maximum concentrations, at which ionic liquids formed stable mixtures in the base oil, either dissolved or as self‐stabilized emulsions. Steel/steel contacts lubricated with such saturated rapeseed oil blends were investigated in a reciprocating sliding tester at room temperature and at 100°C. For most anions, a significant reduction of friction and wear was found at ionic liquid concentrations of less than 0.1 weight%. At substantially higher concentrations, a destabilisation of the ionic liquid–ester mixtures was observed, which was accompanied by a loss of wear‐preventive properties. Copyright © 2014 John Wiley & Sons, Ltd.

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The influence of base oil polarity on the tribological performance of zinc dialkyl dithiophospate additives

Cited by 62 publications

References 40 publications

XPS analysis on the influence of water on the evolution of zinc dialkyldithiophosphate–derived reaction layer in lubricated rolling contacts

XPS analysis on the influence of water on the evolution of zinc dialkyldithiophosphate–derived reaction layer in lubricated rolling contacts

A study on tribological behaviours of ZDDP in polymer thickened lubricating greases

Miscibility and tribological investigations of ionic liquids in biodegradable esters

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