Relationship between mechanical properties and structures of zinc dithiophosphate anti–wear films

Bec, Sandrine; Tonck, A.; Georges, J. M.; Coy, R. C.; Bell, J. C.; Roper, G. W.

doi:10.1098/rspa.1999.0497

Cited by 172 publications

(190 citation statements)

References 24 publications

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“…These results suggests that the durability of antiwear films are strongly affected by temperature even though high temperature have been reported to favour the formation of thick padlike antiwear phosphate films [43,44]. In addition, the efficacy of the tribofilm is influenced by the equilibrium between film removal, formation and associated mechanical properties [45]. Recent studies on camlobes [18] with secondary ZDDP have shown that high temperature affect the durability of these films, which supports the finding in this work.…”

Section: Scanning Electron Microscopy/energy Dispersive X-rays (Sem/edx)supporting

confidence: 88%

Development of valve train rig for assessment of cam/follower tribochemistry

Ofune

Banks

Morina

et al. 2016

Tribology International

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Component bench tests are a crucial part of a tribology assessment experimental programme for most engines and subsystems. This is because they test the components under conditions simulating the operating characteristics of the system. These have become very important as they shed more light into the friction, wear, lubrication and importantly for this study, the tribochemistry of valve train systems. This work outlines the procedure for the development of a single cam rig (SCR) from a 1.25L FORD Zetec (SE) engine. Friction plots were used to validate the data obtained from the newly developed single cam rig with Mn-phosphate coated and polished follower against a cast iron camshaft. The tribofilm formed using normal and mid Sulphated Ash, Phosphorus and Sulphur (SAPS) 5W-30 oils were evaluated and correlated to the friction and wear properties of the tribopair.Raman and FIB-SEM/EDX investigations of the tribochemical films showed that the normal SAPS oil produced patchy, thick (80-100 nm) and well dispersed tribofilm with better wear prevention capabilities. It was observed that Mid SAPS oil had lower wear prevention due to loosely dispersed and thin tribofilms. Absence of tribofilms at the centre of the insert with this oil also suggests that formation and removal processes are an integral part of the wear mechanisms in highly loaded cam follower systems.

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Section: Scanning Electron Microscopy/energy Dispersive X-rays (Sem/edx)supporting

confidence: 88%

Development of valve train rig for assessment of cam/follower tribochemistry

Ofune

Banks

Morina

et al. 2016

Tribology International

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“…Several works have studied the mechanical properties of ZDDP tribofilms formed in boundary lubricated contacts [13][14][15][16][17][18][19]. These have demonstrated that the properties of the ZDDP tribofilm layers are dependent on applied load [20,21].…”

Section: Mechanical Properties and Durability Of Zddp Tribofilmmentioning

confidence: 99%

A new insight into the interfacial mechanisms of the tribofilm formed by zinc dialkyl dithiophosphate

Parsaeian

Ghanbarzadeh

Eijk

et al. 2017

Applied Surface Science

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Understanding the true interfacial mechanisms involved in the growth of tribofilms generated by Zinc Dialkyl Dithiophosphate (ZDDP) is important because it is the most widely used antiwear additive and there is legislative pressure to find efficient environmentally-friendly replacements. The main focus of this study is to investigate the durability of the ZDDP tribofilm and correlate it to the chemical and physical properties of the glassy polyphosphates.A novel experimental method has been developed to study the effect of lubricant temperature and contact load on tribofilm growth and durability. Results show that physical parameters such as temperature and pressure significantly influence the tribofilm durability. XPS analyses were carried out before suspending the test and after changing the oil to assess the difference in chemical structure of the tribofilm before and after stopping the test. The chemical analyses suggest that there are different chemical properties across the thickness of the tribofilm and these determine the durability characteristics.

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“…This means that there is a chemical heterogeneity of the ta-C coating towards the surface region leading probably to a special surface reactivity in particular in presence of additives molecules. Although the uppermost sliding surface and the underlying area are thought to control macro-scale friction behavior, it is difficult experimentally to estimate shear strength and friction behavior as a function of depth at the nanometer scale [25][26][27][28]. Recently, however, we developed a novel nanoscratch method to elucidate the macro-scale effect of reduced friction in relation to the nanoscale tribological properties [29].…”

Section: Friction Of Steel/dlc In Presence Of Glycerol Mono-oleate (Gmo)mentioning

confidence: 99%

Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

Bouchet

Matta

Le-Mogne

et al. 2007

J. Phys.: Conf. Ser.

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Abstract. We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13 C glycerol. This was complemented by first-principlesbased computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp 3 ) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp 2 and sp 1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp 1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface.

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Relationship between mechanical properties and structures of zinc dithiophosphate anti–wear films

Cited by 172 publications

References 24 publications

Development of valve train rig for assessment of cam/follower tribochemistry

Development of valve train rig for assessment of cam/follower tribochemistry

A new insight into the interfacial mechanisms of the tribofilm formed by zinc dialkyl dithiophosphate

Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

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