<i>In situ</i> tribochemical sulfurization of molybdenum oxide nanotubes

Ripoll, Manel Rodríguez; Tomala, A.; Gabler, Christoph; Dražić, Goran; Pirker, Luka; Remškar, Maja

doi:10.1039/c7nr05830f

Cited by 31 publications

(10 citation statements)

References 43 publications

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“…The error bars on the friction curves are based on three repetitions, showing good reproducibility for all the test conditions. The measured friction coefficient of a reference PAO8 oil was 0.183 ± 0.008, in agreement with the reported value [16]. CDs and Ga@CDs were found to have lower friction coefficient than the base oil: 0.129 ± 0.006 and 0.132 ± 0.005, respectively.…”

Section: Anti-wear (Aw) Properties According To Srv Linear Oscillatiosupporting

confidence: 90%

“…Most of the nanomaterials that have been examined include several elements and are more environmentally-friendly [14]. Definitively nanoscale materials in the form of nano-tubes, nano-particles, and nano-dots have the potential to replace toxic additives in future lubrication technologies [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…It is worth mentioning that unlike CDs and N@CDs, for which several synthetic routes exist, the synthesis of Ga@CDs, as well as other low melting point metals as dopants, has been done by the sonochemical method only [11,16].…”

Section: Introductionmentioning

confidence: 99%

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Tribological Anti-Wear and Extreme-Pressure Performance of Multifunctional Metal and Nonmetal Doped C-based Nanodots

et al. 2019

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Carbon nanodots (CDs) are extensively explored due to their little toxicity, excellent water solubility, and biocompatibility. Particularly, fluorescent CDs have received ever-increasing attention. Nevertheless, up to now, only a few findings have been dedicated to measuring the tribological properties of doped CDs, especially Ga doped CDs (Ga@CDs and nitrogen doped CDs (N@CDs)), and to compare their tribological properties with CDs. Here, we describe a strategy for the low-cost one-pot synthesis of CDs for tribological study. The presented research for the first time describes tribological properties and indicates a possible application of the multifunctional CDs (N@CDs, Ga@CDs, and CDs) as highly specific materials for various tests of engine oils and hydraulic oils. Further, it is stated that the doping of the CDs with various elements can tailor demanding tribological performances like anti-wear and extreme-pressure performances.

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Section: Anti-wear (Aw) Properties According To Srv Linear Oscillatiosupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Tribological Anti-Wear and Extreme-Pressure Performance of Multifunctional Metal and Nonmetal Doped C-based Nanodots

et al. 2019

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“…In this case, even lower torque values can be achieved in the presence of dispersants as well, supporting our observations that, besides exfoliation, tribochemical reactions play a fundamental role during form tapping. A similar resulfurization process has been recently observed on nanolubricants containing MoO 3 nanotubes on the presence of S-containing additives [38].…”

Section: Tablesupporting

confidence: 78%

Performance of nanolubricants containing MoS2 nanotubes during form tapping of zinc-coated automotive components

Ripoll

Tomala

Totolin

et al. 2019

Journal of Manufacturing Processes

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The paper presents the first use of nanolubricants containing MoS 2 nanotubes for form tapping of zinc-coated steel. MoS 2 nanotubes are known for their superb low frictional, anti-wear and extreme pressure properties and have shown a promising performance as nanolubricant additive in many machining and forming applications. However their interfacial interaction with zinc-coated components commonly used in automotive applications and their synergisms and antagonisms with currently used additives in forming oils are two crucial aspects that have not been addressed so far. The assessment of these synergies is of uttermost importance for developing future nanofluid minimum quantity lubrication formulations, since despite their extraordinary performance, MoS 2 nanotubes are not able to fulfil all the roles expected from a forming oil. To this end, this paper aims to investigate the performance of MoS 2-based nanolubricants in combination with representative forming oil additives. The threads are perform using a form tapping unit with customized data acquisition on zinc-coated steel, as a representative part in automotive applications. The performance of the nanolubricants is thoroughly investigated using advanced analytic methods with the aim of revealing the underlying interface interaction mechanisms for the observed torque behaviour and resulting thread morphology and sub-surface hardness. The results show that MoS 2 nanotubes are able to interact and form a tribofilm in Zn coated surfaces that leads to a superb friction performance. In combination with oil additives, MoS 2 based nanolubricants have a particularly positive synergy with extreme pressure additives in terms of friction reduction, sub-surface hardening and thread morphology. On contrary, the lowest synergy is achieved in the presence of dispersants, leading to higher torques during form tapping and higher sub-surface hardness in the formed threads.

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“…However, modern industrial elements require additionally other properties such as oxidation and corrosion protection or sludge control to provide a comprehensive protection against degradation. As a consequence, the use of conventional additives as extreme pressure (EP) and anti-wear (AW) additives are typically adopted to improve the tribological performance of a liquid lubricants in reducing surface damage under severe conditions [11,16,17]. Only few researchers were intending to use NPs in fully formulated lubricants, and it was found that the presence of other coexisting additives can influence their performance dramatically [18,19].…”

Section: Introductionmentioning

confidence: 99%

Synergisms and antagonisms between MoS2 nanotubes and representative oil additives under various contact conditions

Tomala

Ripoll

Kogovšek

et al. 2019

Tribology International

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MoS 2 nanotubes are known to enhance the tribological properties of lubricants thanks to support friction-reducing and anti-wear properties. However, in fully-formulated lubricants particularly for steel elements, other properties such as oxidation and corrosion protection are also necessary to provide a comprehensive lubricating performance and protection against oil degradation. As a consequence, the coexistence of MoS 2 nanotubes with other oil additives is unavoidable in immediate future lubrication technologies. This study investigates the influence of representative oil additives such as anti-wear (AW), extreme pressure (EP), detergents and dispersants on the rheological and tribological performance of lubricant mixtures containing MoS 2 nanotubes (NTs). The results obtained provide a wide overview on which of the current commonly used oil additives have a place in future nanolubricant formulations and which additives need to be reconsidered. In general, the synergy between the oil additives and the MoS 2 nanotubes strongly depends on the contact conditions. The reason lies in the interaction mechanisms between the MoS 2 nanotubes and the lubricated surfaces under the presence of the supplementary additive. MoS 2 have an excellent synergy with AW additives under mixed rolling/sliding conditions due to the exfoliation of MoS 2 platelets on top of the AW tribofilm. Under reciprocating sliding, the interaction between the MoS 2 nanotubes and dispersant leads to higher antagonisms. Under extreme pressure unidirectional sliding, their synergy is better with S containing EP additives.

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In situ tribochemical sulfurization of molybdenum oxide nanotubes

Cited by 31 publications

References 43 publications

Tribological Anti-Wear and Extreme-Pressure Performance of Multifunctional Metal and Nonmetal Doped C-based Nanodots

Tribological Anti-Wear and Extreme-Pressure Performance of Multifunctional Metal and Nonmetal Doped C-based Nanodots

Performance of nanolubricants containing MoS2 nanotubes during form tapping of zinc-coated automotive components

Synergisms and antagonisms between MoS2 nanotubes and representative oil additives under various contact conditions

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