Tribological and physicochemical characterization of strontium colloidal additives in mild wear regime

Mansot, Jean-Louis; Golabkan, V.; Romana, Laurence; Bilas, Philippe; Alleman, E; Bercion, Y.

doi:10.1016/j.colsurfa.2004.02.024

Cited by 7 publications

(6 citation statements)

References 16 publications

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“…Because the SrTiO3 can be described by stacking of TiO2 and SrO layers, the O 1s absorption spectrum of this structure is a superposition of the TiO2 and SrO spectra displaying separately each structure. The analysis of energy position of O 1s-absorption spectra of TiO2 [23,30,34,51] and SrO [52] indicates that these spectra differ significantly from each other in the energy positions of the main spectral details that allow their separate analysis. It should be also noted that according to [30,[53][54][55], in the pre-edge region of OK-absorption spectrum of non-stoichiometric SrTiO3 there is a feature connected with oxygen defect states.…”

Section: Iron 2p X-ray Absorptionmentioning

confidence: 99%

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

et al. 2017

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We present a study of the electronic and atomic structure of two series of SrTi1-xFexO3-δ (STFO) powders with different Fe content produced by two different methods, spray pyrolysis or modified Pechini synthesis, by means of soft X-ray absorption spectroscopy. Partial substitution of Ti by Fe atoms in SrTiO3 were found to cause asymmetric distortion of TiO6 octahedrons which increases with increasing Fe content that may violate the cubic symmetry of STFO. The presence mainly of Fe 3+ states in octahedral environment at small concentration of Fe atoms along with essentially smaller content of Fe 4+ states in octahedral environment where the latter contribution increases with increasing Fe content was traced. It is found that the modified Pechini method allows to synthesize more stable structures but a tendency of the SrOx formation in the structure prepared by this technique was marked. The spray pyrolysis method gives the structure free of SrO precipitates but the presence of Fe 3+ states in tetrahedral environment with Fe content higher than 50% and even a certain amount of Fe 2+ ions in an octahedral environment at concentrations higher than 75% in the STFO prepared by this method was established. The O1s (K)-absorption spectra point to increase in oxygen vacancy concentration with increasing Fe content. The lowest degree of structure distortions with enough high oxygen vacancy concentration was traced in STFO (x= 0.25 to x = 0.35) produced by modified Pechini synthesis, which makes it mostly appropriate for technical applications, e.g., as gas sensors, oxygen separation membranes or as fuel cell material.

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Section: Iron 2p X-ray Absorptionmentioning

confidence: 99%

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

et al. 2017

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“…The friction reduction process is classically attributed to the weak interactions between the sheets [11]. Recent works realized on new synthesized carbonaceous nanoparticles (fullerenes, carbon-onions, nanotubes, nanofibres) and inorganic fullerenes and nanotubes (IF-MoS 2 , IF-WS 2 ) gave a lot of informations about the friction reduction processes, involving nanotubes or fullerenes delamination and deposition of graphite layers of some nanometres thickness in the contact area [14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…Due to these limitations, new strategies have been investigated. They consist in the introduction, in the lubricant base, of nanoparticles of tribo-active phases (MoS 2 , graphite) [11][12][13] or precursors of tribo-active phases (fullerenes, carbon-onions, carbon nanotubes, inorganic fullerenes and nanotubes, …) [14][15][16][17][18][19][20][21][22] subjected to build on the sliding surfaces, in the physical conditions of the sliding interface, the tribofilm without any chemical reactions with the substrates. Additionally, the immediate formation of the tribofilm can be obtained in the case of optimized formulation as far as the tribo-active nanoparticles are expected to instantaneously form the tribologic film in the sliding contact.…”

Section: Introductionmentioning

confidence: 99%

Friction Properties of Fluorinated Carbon Nanodiscs and Nanocones

Pandorf¹,

Himmel²,

Mansot³

et al. 2010

Tribol Lett

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The tribologic properties of carbon nanodiscs and nanocones and their fluorinated derivatives are investigated and correlated to their structure and chemical composition (atomic fluorine/carbon ratio). Two families of products are studied obtained by fluorination of ill ordered and highly graphitized carbon nanodiscs and nanocones. The studies clearly point out that friction properties of the nanoparticles are strongly dependent on the structure of the initial carbonaceous compounds. Better tribologic behaviour is obtained when the initial nanoparticles structure is highly ordered (graphitized particles). In that case, an optimum of fluorination rate is put in evidence.

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“…If the molecular layer is formed from a dispersion of molecules into an hydrocarbon base oil embedding the sliding contact, the friction can remain stable at a relatively low value as far as continuous adsorption of amphiphilic molecules on the sliding surfaces occurs [27].…”

Section: Measurement Of the Fiction Coefficientmentioning

confidence: 99%

“…In order to simplify the tribologic results interpretation [62,63], the colloidal additives are introduced alone in a model mineral base oil of low viscosity, normal dodecane, and the tribologic properties are evaluated using the alternative sphere on plane tribometer presented in figure 3. The main parameters of the experiments are summarized in table 2.…”

Section: Tribologic Properties Of the Two Types Of Colloidal Systemsmentioning

confidence: 99%

Nanolubrication

Mansot¹,

Bercion²,

Romana³

et al. 2009

Braz. J. Phys.

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Lubrication strategies developed long time ago employed amphiphilic molecular lubricant additives to confer to lubricating oils or greases specific properties such as friction reduction, antiwear, anticorrosion. The understanding of their action and the development of various type of nanoparticles are at the origin of new lubrication strategies using composite or functionalized nanoparticles in dispersion in lubricating oils or greases to confer to the lubricants the needed functions. The present work is concerned with the presentation of these new approaches. Some examples will be developed to show the main aspects of the mechanisms of action of these new nano-additives.

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Tribological and physicochemical characterization of strontium colloidal additives in mild wear regime

Cited by 7 publications

References 16 publications

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Friction Properties of Fluorinated Carbon Nanodiscs and Nanocones

Nanolubrication

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