Revealing the interface nature of ZDDP tribofilm by X-ray photoelectron spectroscopy and atom probe tomography

2020 ◽  
Vol 72 (7) ◽  
pp. 923-930
Author(s):  
Chia-Jui Hsu ◽  
Jenifer Barrirero ◽  
Rolf Merz ◽  
Andreas Stratmann ◽  
Hisham Aboulfadl ◽  
...  
Keyword(s):  
Peer Review ◽  
Photoelectron Spectroscopy ◽  
Atom Probe Tomography ◽  
Steel Substrate ◽  
Atom Probe ◽  
Engine Oil ◽  
Content Type ◽  
X Ray ◽  
Sliding Test ◽  
Cylindrical Roller

Purpose To decrease wear and friction, zinc dialkyldithiophosphate (ZDDP) has been used in engine oil for several decades, but the mechanism of the tribofilm formation is still unclear. The purpose of this study is to characterize the chemical details of the tribofilm by using high-resolution approaching. Design/methodology/approach An ISO VG 100 mineral oil mixed with ZDDP was used in sliding tests on cylindrical roller bearings. Tribofilm formation was observed after 2 h of the sliding test. X-ray photoelectron spectroscopy (XPS) and atom probe tomography (APT) were used for chemical analysis of the tribofilm. Findings The results show that the ZDDP tribofilm consists of the common ZDDP elements along with iron oxides. A considerable amount of zinc and a small amount of sulfur were observed. In particular, an oxide interlayer with sulfur enrichment was revealed by APT between the tribofilm and the steel substrate. The depth profile of the chemical composition was obtained, and a tribofilm of approximately 40 nm thickness was identified by XPS. Originality/value A sulfur enrichment at the interface is observed by APT, which is beneath an oxygen enrichment. The clear evidence of the S interlayer confirms the hard and soft acids and bases principle. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/

On the Behavior of Yttria/Yttrium during Mechanical Alloying of a Fe - Y2O3 Model Alloy System

2014 ◽  
Vol 922 ◽  
pp. 598-603
Author(s):  
Gerald Ressel ◽  
Peter Parz ◽  
Alexander Fian ◽  
David Holec ◽  
Sophie Primig ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Positron Annihilation ◽  
Photoelectron Spectroscopy ◽  
Atom Probe Tomography ◽  
Elevated Temperatures ◽  
Positron Annihilation Spectroscopy ◽  
Atom Probe ◽  
Model Alloy ◽  
High Temperature Strength ◽  
X Ray

Mechanical alloying (MA) is an established way to prepare nanocrystalline materials and metastable solutions of materials, which normally have no mutual solubility. This is also the case for oxide dispersion strengthened (ODS) steels with improved mechanical properties at elevated temperatures. It is known that a small addition of yttria (Y2O3) has a beneficial effect on high temperature strength and reduces the creep rate in mechanically alloyed ferritic steels by about six orders of magnitude. In this work we present an experimental study using atom probe tomography, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy combined with first principles modeling focusing on the distribution and behavior of yttria in pure iron prepared by mechanical alloying. Atom probe tomography and X-ray photoelectron spectroscopy measurements as well as positron annihilation spectroscopy conducted on powder particles directly after milling have revealed that a predominantly fraction of the yttria powder dissolves in the iron matrix and Y atoms occupy convenient positions, such as vacancies or dislocations. This is supported by ab initio calculations demonstrating that the formation energy for Y substitutional defects in bcc-Fe is significantly lower in the close neighborhood of vacancies.

Effect of engine oil additives reduction on the tribofilm structure of a cylinder liner model surface

2019 ◽  
Vol 72 (4) ◽  
pp. 515-523
Author(s):  
Maria de Lourdes Miranda-Medina ◽  
Christian Tomastik ◽  
Tia Truglas ◽  
Heiko Groiss ◽  
Martin Jech
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cylinder Liner ◽  
Engine Oil ◽  
Antiwear Additives ◽  
Content Type ◽  
X Ray ◽  
Underlying Mechanisms

Purpose The purpose of this paper is to provide a general picture for describing the formed tribofilm, including chemical and physical aspects in the micro-scale and the nano-scale. In a previous study, the durability of zinc dialkyl dithiophosphate (ZDDP) tribofilms on cylinder liner samples has been investigated in a tribometer model system by using fresh and aged fully formulated oils and replacing them with PAO8 without additives. Analyses of the derived tribofilms by means of X-ray photoelectron spectroscopy and scanning electron microscopy could give some hints about the underlying mechanisms of the tribofilm build-up and wear performance, but a final model has not been achieved. Design/methodology/approach Thus, characterisation of these tribofilms by means of focused ion beam-transmission electron microscopy (FIB-TEM) and energy dispersive X-ray spectroscopy is presented and a concluding model of the underlying mechanisms of tribofilm build-up is discussed in this paper. Findings For tribotests running first with fresh fully formulated engine oil, a rather homogeneous ZDDP-like tribofilm is found underneath a carbon rich tribofilm after changing to non-additivated PAO8. However, when the tests run first with aged fully formulated engine oil, no ZDDP-like tribofilm has been found after changing to non-additivated PAO8, but a wear protective carbon rich tribofilm. Originality/value The obtained results provide insights into the structure and durability of tribofilms. Carbon-based tribofilms are built up on the basis of non-additivated PAO8 because of the previously present ZDDP tribofilms, which suggests an alternative way to reducing the consumption of antiwear additives.

scholarly journals Mapping nitrogen heteroatoms in carbon fibres using atom probe tomography and photoelectron spectroscopy

Carbon ◽  
2021 ◽  
Author(s):  
Marcus Johansen ◽  
Christoph Schlueter ◽  
Pui Lam Tam ◽  
Leif E. Asp ◽  
Fang Liu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Carbon Fibres

Skidding research of a high-speed cylindrical roller bearing with beveled cage pockets

2020 ◽  
Vol 72 (7) ◽  
pp. 969-976
Author(s):  
Yanbin Liu ◽  
Zhanli Zhang
Keyword(s):  
Peer Review ◽  
Tilt Angle ◽  
High Speed ◽  
Hydrodynamic Lubrication ◽  
Roller Bearing ◽  
Front Wall ◽  
Dynamics Model ◽  
Content Type ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Purpose This study aims to uncover the influencing mechanism of the tilt angles of the cage pocket walls of the high-speed cylindrical roller bearing on the bearing skidding. Design/methodology/approach A novel cylindrical roller bearing with the beveled cage pockets was proposed. Using the Hertz contact theory and the elastohydrodynamic and hydrodynamic lubrication formulas, the contact models of the bearing were built. Using the multibody kinematics and the Newton–Euler dynamics theory, a dynamics model of the bearing was established. Using the Runge–Kutta integration method, the dynamics simulations and analysis of the bearing were performed. Findings The simulation results show that the effects of the tilt angles of the front and rear walls of the pocket on the bearing skidding are remarkable. Under a 5° tilt angle of the front wall of the pocket and a 10° tilt angle of the rear wall, the bearing skidding can be effectively decreased in the rotational speed range of 10,000-70,000 r/min. Originality/value In this paper, a novel cylindrical roller bearing with the beveled cage pockets was proposed; a dynamics model of the bearing was established; the influence mechanism of the tilt angles of the front and rear walls of the pocket on the bearing skidding was investigated, which can provide fundamental theory basis for optimizing the pocket. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/

The influence of Ni on the microstructure and corrosion resistance of high-strength low alloy steel in the Cl-containing environment

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dan Wang ◽  
Qingdong Zhong ◽  
Jian Yang ◽  
Shujian Zhang
Keyword(s):  
Corrosion Resistance ◽  
Alloy Steel ◽  
Photoelectron Spectroscopy ◽  
Hsla Steel ◽  
Electrochemical Techniques ◽  
High Strength ◽  
Low Alloy Steel ◽  
Transfer Resistance ◽  
Content Type ◽  
X Ray

Purpose This paper aims to search the optimum content of Ni on the microstructure, phase and electrochemical behavior of high-strength low alloy (HSLA) steel in the 3.5 wt.% NaCl solution. Design/methodology/approach The microstructure and corrosion resistance of Ni-containing HSLA steel in the simulated marine environment was studied by optical microscopy, scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Findings The sample containing 3.55 wt.% of nickel exhibited a finer grain size of 10 μm and a lower icorr of 2.169 µA cm−2. The XRD patterns showed that the Fe-Cr-Ni solid solution, FeC and Cr3C2 were observed in samples when Ni was added. Besides, the 3.55 wt.% of nickel addition enhanced the charge transfer resistance of the low alloy steel which suggested the sample possessed excellent inhibition of electrochemical reaction and corrosion resistance. The XPS spectrum suggested that nickel was beneficial to improve the corrosion resistance of steel by forming protective oxides, and the ratio of Fe2+/Fe3+ in protective oxides was increased. Practical implications Finding the comprehensive performance of HSLA steel which can be applied to unmanned surface vehicles in marine operations. Originality/value This study has a guiding significance for optimizing the composition of HSLA steel in a Cl- containing environment.

Influence of nitrite on chemical composition of passivation film of steel bars under the coupling effects of carbonization and chloride

2019 ◽  
Vol 66 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Junzhe Liu ◽  
Jundi Geng ◽  
Hui Wang ◽  
Mingfang Ba ◽  
Zhiming He
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Chloride Solution ◽  
Layer Structure ◽  
Coupling Effects ◽  
Content Type ◽  
X Ray ◽  
Passivation Film ◽  
Steel Bars ◽  
Micro Structures

Purpose This paper aims to study the influence of NaNO2 on the chemical composition of passivation film. Design/methodology/approach X-ray photoelectron spectroscopy and X-ray diffraction were selected to determine the composition of passivation film of steel bars in mortar. The specimens were exposed to the chloride solution, carbonation environment and the coupling effects of chloride solution and carbonation. The chemical composition and micro structures at 0 and 5 nm from the outer surface of the passivation film of steel bars were analyzed. Findings Results showed that the nitrite inhibitor improved the forming rate of the passivation film and increased the mass ratio of Fe3O4 to FeOOH on the surface of steel bars. The component of Fe3O4 at 5 nm of the steel passivation film was more than that at 0 nm. Sodium ferrite in the pore solution was easily hydrolyzed and then FeOOH was formed. Therefore, due to the nitrite inhibitor, a “double layer structure” of the passivation film was formed to prevent steels bars from corrosion. Originality/value This is original work and may help the researchers further understand the mechanism of rust resistance by nitrite inhibitor.

Synergistic effects of antiwear and friction modifier additives

2020 ◽  
Vol 72 (8) ◽  
pp. 1019-1025
Author(s):  
Jennifer Eickworth ◽  
Enes Aydin ◽  
Martin Dienwiebel ◽  
Thomas Rühle ◽  
Patrick Wilke ◽  
...  
Keyword(s):  
Peer Review ◽  
Photoelectron Spectroscopy ◽  
Synergistic Effects ◽  
Film Formation ◽  
Wear Volume ◽  
Friction Modifier ◽  
Quartz Crystals ◽  
Content Type ◽  
Representative Study ◽  
Wear Reduction

Purpose Interactions of different additive types for antiwear/friction modification on surfaces can be synergistic or antagonistic in nature. This paper aims to investigate whether there are interactions between different additives in the adsorption process and whether they synergistic or antagonistic. The yielded correlations will be validated with tribological experiments to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction. Design/methodology/approach In a representative study, zinc dialkyl-dithiophosphate and dithiophosphate were elaborated in combination with two different friction modifiers, a glycerol monooleate and an organic friction modifier. As base oils, mineral oil and poly alpha olefine were used. The adsorption behavior was studied via quartz crystal microbalance with dissipation using Fe2O3 coated quartz crystals. The tribological performance was evaluated in a ball-on-three disk tribometer. White light interferometry was used to determine the wear volume and X-ray photoelectron spectroscopy depth profiles of the tribofilms were obtained on selected systems. Findings The combination of dithiophosphate and an organic friction modifier (OFM) revealed a synergistic effect in terms of wear. If the initially formed films are viscoelastic, the third body formation during a tribo experiment is more pronounced and thereby wear can be reduced. As a mechanism, the adsorption of the OFM on the formed antiwear layer is proposed. Originality/value Correlating the analytical findings with performance experiments provides further understanding of the interactions between different constituents and their implications on film formation processes and wear reduction mechanisms. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0293/

Comparison studies of the protective properties of silane/polyrhodanine and polyrhodanine/silane bilayer coatings applied on stainless steel

2018 ◽  
Vol 65 (2) ◽  
pp. 190-196 ◽  
Author(s):  
Edyta Owczarek
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Steel Surface ◽  
Steel Substrate ◽  
Dip Coating ◽  
Stainless Steel Surface ◽  
Protective Properties ◽  
Content Type ◽  
Anticorrosion Properties ◽  
Bilayer Coatings

Purpose The purpose of this paper is to evaluate and compare the protective, anticorrosion properties of silane- and polyrhodanine-based bilayer coatings pRh/IBTES and IBTES/pRh on an X20Cr13 stainless steel substrate. Design/methodology/approach IBTES/pRh and pRh/IBTES have been coated using the dip-coating method and the cyclic voltammetry technique. The electrochemical measurements have been used to assess the anticorrosion properties of the resulting bilayer coatings. Morphological and chemical characterizations have been performed using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Findings The results clearly show that the combination of both the deposits of polyrhodanine and silane yields a more protective structure that affords better protection against corrosion with time. The best barrier properties are achieved by the substrates coated with polyrhodanine film upon which silane is subsequently adsorbed – the pRh/IBTES bilayer coating. Originality/value The paper reveals that the procedure of modification of silane films with polyrhodanine had a marked effect on the anti-corrosive performance of the obtained two types of bilayers coatings (pRh/IBTES, IBTES/pRh) applied on a stainless steel surface. The coating where polyrhodanine was first electrodeposited on the steel surface and then the silane layer adsorbed (pRh/IBTES) achieved the best protective properties.

scholarly journals Characteristics of Carbide Interfacial Layer Formed During Deposition of DLC Films on 316L Stainless Steel Substrate

2017 ◽  
Vol 62 (4) ◽  
pp. 2211-2216 ◽  
Author(s):  
M. Dudek
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
316L Stainless Steel ◽  
Steel Substrate ◽  
Carbon Film ◽  
Ex Situ ◽  
Second Phase ◽  
X Ray ◽  
Dlc Film

AbstractThe paper presents the analysis of formation of interfacial layer during deposition of diamond like carbon film (DLC) on the 316L stainless steel by capacitive plasma discharge in the CH4atmosphere. The structure of the interfacial layer of DLC film was strongly affected by the temperature increase during the initial stages of the process. Initially, thin interfacial layer of 5 nm has been formed. As the temperature had reached 210°C, the second phase of the process was marked by the onset of carbon atoms diffusion into the steel and by the interface thickness increase. Finally, the growth of chromium carbide interface, the upward diffusion of chromium and nickel atoms to film, the etching and the decrease of the DLC film thickness were observed at 233°C. These investigations were carried out ex-situ by spectroscopic ellipsometry, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy.

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