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Kaltchev, M.; Kotvis, Peter V.; Blunt, T. J.; Lara, J.; Tysoe, Wilfred T.

doi:10.1023/a:1009020725936

Cited by 27 publications

(19 citation statements)

References 23 publications

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“…STM images were acquired at 300 K. Temperature-programmed desorption data were collected in a different ultrahigh vacuum chamber also operating at a base pressure of B1 Â 10 À10 Torr as described elsewhere. 33 The Au(111) surface was cleaned with cycles of bombardment of the surface with 1 keV argon ions for 30 min, annealing to 900 K for 5 min and then to 600 K for 30 min until cleanliness was verified by obtaining a perfectly defined herringbone reconstruction by scanning-tunneling microscopy (STM) or by Auger spectroscopy. PDI was sublimed from a homemade Knudsen source 34 that was thermostated at 0 1C and dosed on a clean Au(111) surface held at 300 K.…”

Section: Methodsmentioning

confidence: 99%

One-dimensional supramolecular surface structures: 1,4-diisocyanobenzene on Au(111) surfaces

Boscoboinik

Calaza

Habeeb

et al. 2010

Phys. Chem. Chem. Phys.

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One-dimensional supramolecular structures formed by adsorbing low coverages of 1,4-diisocyanobenzene on Au(111) at room temperature are obtained and imaged by scanning tunneling microscopy (STM) under ultrahigh vacuum (UHV) conditions. The structures originate from step edges or surface defects and arrange predominantly in a straight fashion on the substrate terraces along the <110> directions. They are proposed to consist of alternating units of 1,4-diisocyanobenzene molecules and gold atoms with a unit cell in registry with the substrate corresponding to four times the lattice interatomic distance. Their long 1-D chains and high thermal stability offer the potential to use them as conductors in nanoelectronic applications.

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Section: Methodsmentioning

confidence: 99%

One-dimensional supramolecular surface structures: 1,4-diisocyanobenzene on Au(111) surfaces

Boscoboinik

Calaza

Habeeb

et al. 2010

Phys. Chem. Chem. Phys.

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“…Increasing the additive concentration results in an initially faster rate of ferrous chloride lm formation but, as soon as the interfacial temperature reaches the melting point of the lm material, the wear rate becomes asymptotically large and the lm is removed. This approach has also been used to explore the EP tribochemistry of other chlorine, 32,33,[46][47][48][49][50][51][52][53][54][55][56] sulphur, 57,58 and phosphorus-containing 59,60 lubricant additives.…”

Section: Extreme-pressure Tribochemistry Of Methylene Chloride On Ironmentioning

confidence: 99%

Shear and thermal effects in boundary film formation during sliding

et al. 2014

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A prerequisite for understanding mechano-and tribochemical reaction pathways is that the interface be in thermodynamic equilibrium and that the temperature be well defined. It is suggested that this occurs in two regimes: when the surfaces are only slightly perturbed during sliding, leading to negligible frictional heating, and when the surface temperatures are very high ($1000 K), in the so-called extreme pressure regime. The tribochemistry occurring in each regime is discussed in terms of the elementary steps leading to tribofilm formation, namely (i) a reaction of the additive or gas-phase lubricant on the surface to form an adsorbed precursor, (ii) decomposition of the molecular precursor, (iii) a process that causes the formation of a tribofilm that (iv) regenerates a clean surface that allows this tribochemical cycle to continue to form a thicker film. These steps are thermally driven in the extreme-pressure regime, while under milder conditions, they are induced by interfacial shear. In intermediate situations, the processes are likely to be a combination of those occurring at the extrema.

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“…However, the mechanisms by which these important films form are poorly understood because they arise within a sliding contact that cannot be directly probed experimentally. It has been proposed that such films form when the additive molecules thermally decompose as the temperature increases (on the order of ∼1000 K) in sliding interfaces . More recent studies confirmed that shear is necessary to drive the formation of protective films in some sulfur-containing additives and that reaction kinetics are different for thermal vs shear-driven films .…”

Section: Introductionmentioning

confidence: 99%

Reactive Molecular Dynamics Simulations of Thermal Film Growth from Di-tert-butyl Disulfide on an Fe(100) surface

et al. 2018

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Iron sulfide films are present in many applications, including lubricated interfaces where protective films are formed through the reactions of lubricant additive molecules with steel surfaces during operation. Such films are critical to the efficiency and useful lifetime of moving components. However, the mechanisms by which films form are still poorly understood because the reactions occur between two surfaces and so cannot be directly probed experimentally. To address this, we explore the thermal contribution to film formation of di-tert-butyl disulfidean important extreme pressure additiveon an Fe(100) surface using reactive molecular dynamics simulations, where the reactive potential parameters are validated by comparison to ab initio calculations. The reaction pathway leading to the formation of iron sulfide surfaces is characterized using the reactive simulations. Then, the film formation process is mimicked by simulations where di-tert-butyl disulfide molecules are cyclically added to the surface and subjected to temperatures comparable to those expected due to frictional heating. The use of a reactive empirical potential is a novel approach to modeling the iterative nature of thermal film growth with realistic lubricant additive molecules.

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Untitled

Cited by 27 publications

References 23 publications

One-dimensional supramolecular surface structures: 1,4-diisocyanobenzene on Au(111) surfaces

One-dimensional supramolecular surface structures: 1,4-diisocyanobenzene on Au(111) surfaces

Shear and thermal effects in boundary film formation during sliding

Reactive Molecular Dynamics Simulations of Thermal Film Growth from Di-tert-butyl Disulfide on an Fe(100) surface

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