Time-Dependent Film Formation from ZnDTPs and Nonphosphorus Antiwear Agents

Yamaguchi, E. S.; Roby, S. H.; Yeh, Sung-Wei

doi:10.1080/05698190590899949

Cited by 12 publications

(14 citation statements)

References 17 publications

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“…The proportion of Zn in the tribofilm has decreased 6 times, while the amounts of phosphates and sulphides are overall 1-2% smaller than those found in the BO+ZDDP film. This behavior is consistent with the results reported by other published studies that investigated the effect of detergents and dispersants on ZDDP tribofilm formation [11,18].…”

Section: Zddp In Base Oil and Blosupporting

confidence: 93%

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The impact of organic friction modifiers on engine oil tribofilms

et al. 2014

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Organic friction modifiers (OFMs) are important additives in the lubrication of machines and especially of car engines where performance improvements are constantly sought-after. Together with zinc dialkyldithiophosphates (ZDDPs) antiwear additives, OFMs have a predominant impact on the tribological behaviour of the lubricant. In the current study, the influence of OFMs on the generation, tribological properties and chemistry of ZDDP tribofilms has been investigated by combining tribological experiments (MTM) with in-situ film thickness measurements through optical interference imaging (SLIM), Alicona profilometry and X-ray photoelectron spectroscopy.OFMs and antiwear additives have been found to competitively react/adsorb on the rubbing ferrous substrates in a tribological contact. The formation and removal (through wear) of tribofilms are dynamic processes which result from the simultaneous interaction of these two additives with the surface of the wear track.By carefully selecting the chemistry of OFMs, the formulator can achieve lubricants that generate ZDDP antiwear films of optimum thickness, morphology and friction according to the application-specific requirements.

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Section: Zddp In Base Oil and Blosupporting

confidence: 93%

“…The reason for the high interest in MoDTC is that aside from being a FM, it is also one of the most efficient non-phosphorous antiwear additives [11], shown to synergize well with ZDDP to reduce wear and friction [10,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The impact of organic friction modifiers on engine oil tribofilms

et al. 2014

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“…Therefore, in this study, the data were averaged from the original data obtained at the four positions when there was a rotation of the cylinder. Figure 3 shows that the separation ratio of ZnDTP mono-blend increased drastically and progressed from a value of zero up to a value of 1 by less than the distance of 50 m. The separation ratio, which was determined by dividing the measured voltage by the voltage applied between the two specimens, was used to evaluate the film formation, representing a complete separation by a ratio of 1 and a complete contact by a ratio of zero [20]. This demonstrated that ZnDTP formed a nonconductive film on friction surfaces soon after the friction test began, and that the film was present at the contact without film separation throughout the friction test.…”

Section: Sample Lubricant Oilsmentioning

confidence: 99%

“…On the other hand, the separation ratios obtained from the four kinds of mono-blends-DISP, DET, MoDTC, and StA-were low, ranging in value from 0 to 0.2, while the separation ratio from ZnDTP increased sharply and reached one as mentioned above. This is because the four kinds of monoblends did not form as thick a film as ZnDTP did, or because the reaction film had high electrical conductivity even if it did form such a film; for example, MoDTC formed molybdenum sulfide (MoS 2 ), which has a high conducting property [20]. Figure 6 compares the experimental results for four kinds of binary-blend oils with that for ZnDTP mono-blend oil at the running-in period.…”

Section: Sample Lubricant Oilsmentioning

confidence: 99%

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Effect of Coexistent Additives on the Friction Characteristics and Tribofilm formation of Zinc Dialkyldithiophosphate

Aoki¹,

Masuko²,

Suzuki³

2007

SAE Technical Paper Series

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The major aim of this study is to investigate the tribofilm formation and friction-speed characteristics of ZnDTP in the presence of other lubricant additives. Simultaneous measurement of friction and electrical conductivity were employed using ZnDTP and several kinds of functionally different additives. Several analyses of friction surfaces were also carried out in order to measure the reaction film thickness and investigate the chemical composition of this film. It was demonstrated that the presence of each additive with ZnDTP prevented the formation of a ZnDTP tribofilm and thereby could provide lower friction than ZnDTP alone.

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Development of zero‐phosphorus engine oils

Gangopadhyay

Jensen

Carter

et al. 2007

Lubrication Science

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Poisoning by phosphorus in engine oil limits the useful life of automotive catalysts. The amount of phosphorus in engine oil has been decreasing for over a decade, and currently is limited to 0.08 wt% maximum. The source of phosphorus in engine oil is zinc dialkyldithiophosphate, which is a very effective antioxidant and anti‐wear compound. Therefore, elimination of phosphorus in engine oil requires replacement of both anti‐wear and antioxidation functions with novel additive compounds. This research describes the current state of developing zero‐phosphorus engine oils while maintaining GF‐4 performance attributes. A systematic approach was taken for this development beginning with the base oil and viscosity modifier system selection, followed by antioxidant compounds selection, and then anti‐wear compound selection. The effectiveness of antioxidant and anti‐wear compounds was evaluated using a laboratory oxidation test, and friction and wear tests when the oil was both fresh and aged. The oil showing the most promising result was evaluated in industry accepted TEOST MHT 4 for oxidation, and ASTM Sequence IIIG test for high temperature wear and piston deposits. Results to date show excellent oxidation characteristics, but wear control requires further work. Analysis of surface films showed the presence of carbonate and iron oxide when the oil was fresh, but only iron oxide when tested with 40 and 100 h aged oil samples from the Sequence IIIG test. Copyright © 2007 John Wiley & Sons, Ltd.

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Time-Dependent Film Formation from ZnDTPs and Nonphosphorus Antiwear Agents

Cited by 12 publications

References 17 publications

The impact of organic friction modifiers on engine oil tribofilms

The impact of organic friction modifiers on engine oil tribofilms

Effect of Coexistent Additives on the Friction Characteristics and Tribofilm formation of Zinc Dialkyldithiophosphate

Development of zero‐phosphorus engine oils

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