Antiwear tribofilm growth in rolling bearings under boundary lubrication conditions

Stratmann, Andreas; Jacobs, Georg; Hsu, Chia-Jui; Gachot, Carsten; Burghardt, Gero

doi:10.1016/j.triboint.2017.03.030

Cited by 24 publications

(20 citation statements)

References 41 publications

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“…The lubrication condition based on the film thickness was calculated according to Dowson et al [30,31]. The lambda values of the experiments were between 0.04 and 0.12, indicating that all the tests were conducted under boundary lubrication conditions [32]. Further information on the experiments can be found in Table 2.…”

Section: Rolling Bearing Test Rigmentioning

confidence: 99%

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Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

et al. 2021

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Laser surface texturing (LST) has been proven to improve the tribological performance of machine elements. The micro-scale patterns manufactured by LST may act as lubricant reservoirs, thus supplying oil when encountering insufficient lubrication. However, not many studies have investigated the use of LST in the boundary lubrication regime, likely due to concerns of higher contact stresses that can occur with the increasing surface roughness. This study aims to examine the influence of LST on the fatigue lifetime of thrust rolling bearings under boundary lubrication. A series of periodic patterns were produced on the thrust rolling bearings, using two geometrically different designs, namely cross and dimple patterns. Base oil ISO VG 100 mixed with 0.05 wt% P of zinc dialkyldithiophosphate (ZDDP) was supplied. The bearings with cross patterns reduce the wear loss by two orders of magnitude. The patterns not only retain lubricant in the textured pockets but also enhance the formation of an anti-wear tribofilm. The tribofilm generation may be improved by the higher contact stresses that occur when using the textured surface. Therefore, in contrast to the negative concerns, the ball bearings with cross patterns were instead found to increase the fatigue life by a factor of three.

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Section: Rolling Bearing Test Rigmentioning

confidence: 99%

“…Zinc dialkyldithiophosphate (ZDDP), which is one of the most popular oil additives, was used in this study. It has been shown that the presence of the ZDDP tribofilm reduces wear [17][18][19]. The layer is often described as an island-like thin-film, with a thickness of around 100 nm and width from 0.5 to several micrometers [8,20].…”

Section: Introductionmentioning

confidence: 99%

Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

et al. 2021

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“…After the test, the surface was cleaned by using benzene and isopropanol to remove the residual lubricant, abrasives, and contaminants. More details regarding the test rig and testing parameters can be found elsewhere [25].…”

Section: Fe8 Test Rigmentioning

confidence: 99%

Enhanced Growth of ZDDP-Based Tribofilms on Laser-Interference Patterned Cylinder Roller Bearings

et al. 2017

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Abstract:Laser surface texturing has been successfully applied in the past to various machine elements in order to improve their tribological performance. In this study, direct laser interference patterning was used to produce periodic cross-like surface patterns on commercial cylinder roller bearings. The wear behavior of as-patterned bearings was studied by a modified FE8 test rig under boundary lubrication. A mineral oil (ISO VG 100) as a base oil additivated with 0.02 wt % zinc dialkyldithiophosphate (ZDDP) was used for the tribological tests which were performed under a Hertzian pressure of 1.92 GPa and maintained at 80 • C and 20 rpm for 2 h. The laser-patterned bearings showed a significantly reduced mass loss by two orders of magnitude compared to the unpatterned reference bearings. A closer look at the samples proved the formation of the characteristic blue-colored ZDDP tribofilm on top of the laser-induced topography maximum positions. Due to the higher contact pressure at the laser-induced peaks, the tribofilm formation was preferable at those positions thus protecting against wear. The laser patterns nearly remained unworn compared to the reference samples. A subsequent Raman analysis of the laser-patterned bearings clearly revealed the formation of zinc and iron sulfides as well as phosphates at the peak points.

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“…Zinc-Dialkyldithiophosphates (ZDDP) are the most common group of AW/EP additives and, therefore, used in this study (Barnes et al , 2001; Lugt, 2013; Stratmann et al , 2017). The general molecular formula of ZDDP is Zn [S 2 P(OR) 2 ] 2 , at which R consists of an alkyl or aryl chain (Gosvami et al , 2015).…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on wear performance of greases in rolling bearings

Rosenkranz

Richter

Jacobs

et al. 2021

ILT

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Purpose Rolling bearing operation under mixed and boundary lubrication conditions may lead to heavy adhesive or abrasive wear, which may lead to wear-induced rolling bearing failure. The purpose of this paper is to investigate the wear protection capabilities of different grease compositions at varying temperatures. It is considered that the temperature influences the lubrication conditions, the behaviour of grease components, namely, bleed oil and thickener, as well as the tribofilm formation due to tribo-chemical interactions between additives and surfaces. Design/methodology/approach In this study, four different greases were produced on the basis of a mineral base oil by varying the thickener and the addition of ZDDP. Various grease-lubricated rolling bearing experiments were conducted in a wide temperature range from 0°C to 120°C. Subsequently, the wear pattern, tribofilm formation and grease structures were analysed. Thereby, the influence of the different grease thickeners and the performance of ZDDP as a common antiwear and extreme pressure additive was evaluated. Findings The results show a strong temperature-dependency and allow a classification of temperature ranges concerning wear protection. At low temperatures, all greases provide a very good wear protection without the evidence of additive-based tribofilm formation. In the experiments at elevated temperatures, ZDDP tribofilms were formed. The formation depends on the thickener type: in comparison to lithium thickener, polyurea thickener favours more protective tribofilms at the same temperature. The experimental results show that medium temperatures in the range of 40°C–60°C are critical concerning wear due to the insufficient tribolayer formation and limited load carrying capacity of the grease. Originality/value Temperature is a key operating parameter for grease lubrication in roller bearings. The experimental work enables consideration of different impact pathways of temperature by combining roller bearing tests and microanalysis.

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Antiwear tribofilm growth in rolling bearings under boundary lubrication conditions

Cited by 24 publications

References 41 publications

Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

Enhanced Growth of ZDDP-Based Tribofilms on Laser-Interference Patterned Cylinder Roller Bearings

Influence of temperature on wear performance of greases in rolling bearings

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