Passivation of steel surface: An atomistic modeling approach aided with X-ray analyses

2011 ◽  
Vol 65 (21-22) ◽  
pp. 3223-3226 ◽  
Author(s):  
Tongyan Pan ◽  
Adri C.T. van Duin
Keyword(s):  
Steel Surface ◽  
Atomistic Modeling ◽  
X Ray ◽  
Modeling Approach

Halogens molecular modifications with high pressure: the case of iodine

2021 ◽  
Author(s):  
Jingming Shi ◽  
Emiliano Fonda ◽  
Silvana Botti ◽  
Miguel A. L. Marques ◽  
Toru Shinmei ◽  
...  
Keyword(s):  
High Pressure ◽  
Absorption Spectroscopy ◽  
Diatomic Molecules ◽  
Giant Planets ◽  
Atomistic Modeling ◽  
X Ray ◽  
X Ray Absorption

Metallization and dissociation are key transformations in diatomic molecules at high densities particularly significant for modeling giant planets. Using X-ray absorption spectroscopy and atomistic modeling, we demonstrate that in halogens,...

scholarly journals Synthesis and Characterization of Ni–W/Cr2O3 Nanocomposite Coatings Using Electrochemical Deposition Technique

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 815 ◽  
Author(s):  
Samuel Mbugua Nyambura ◽  
Min Kang ◽  
Jiping Zhu ◽  
Yuntong Liu ◽  
Yin Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Binary Alloy ◽  
Steel Surface ◽  
Nanocomposite Coatings ◽  
Electrodeposition Technique ◽  
X Ray ◽  
Citrate Electrolyte ◽  
Cr2o3 Nanoparticles ◽  
Nanoparticle Content

Ni–W/Cr2O3 nanocomposite coatings were synthesized from aqueous sulphate-citrate electrolyte containing Cr2O3 nanoparticles on a steel surface using conventional electrodeposition technique. This study was aimed at investigating the influence of Cr2O3 nanoparticle content on the microstructure, corrosion resistance, and mechanical properties of electrodeposited Ni–W/Cr2O3 nanocomposite coatings. Ni–W binary alloy coatings were deposited and optimized before addition of the nanoparticles to produce high-quality coatings. The microstructure and chemical composition of the Ni–W/Cr2O3 nanocomposite coatings were evaluated using scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), and XRD. Corrosion resistance properties were evaluated using potentiodynamic polarization (Tafel) measurements in 3.5 wt.% NaCl medium. The corrosion resistance and microhardness are significantly higher in Ni–W/Cr2O3 nanocomposite coatings compared to pure Ni–W binary alloy and increase with the increase in content of Cr2O3 nanoparticles in the coatings. Wear resistance is also higher in Ni–W/Cr2O3 nanocomposite coatings.

Influence of Pyrrhotite on the Corrosion of Mild Steel

CORROSION ◽  
10.5006/2505 ◽  
2017 ◽  
Vol 74 (1) ◽  
pp. 37-49 ◽  
Author(s):  
Saba Navabzadeh Esmaeely ◽  
Gheorghe Bota ◽  
Bruce Brown ◽  
Srdjan Nešić
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Product Layer ◽  
Localized Corrosion ◽  
X Ray Diffraction ◽  
Galvanic Coupling ◽  
X Ray ◽  
H2s Corrosion ◽  
Corrosion Product Layer ◽  
Nacl Concentration

As a result of the electrical conductivity of pyrrhotite, it was hypothesized that its presence in the corrosion product layer on a steel surface could lead to localized corrosion. Mild steel specimens (API 5L X65) were pretreated to form a pyrrhotite layer on the surface using high-temperature sulfidation in oil. The pretreated specimens were then exposed to a range of aqueous CO2 and H2S corrosion environments at 30°C and 60°C. X-ray diffraction data showed that the pyrrhotite layer changed during exposure; in an aqueous CO2 solution it underwent dissolution, while in a mixed CO2/H2S solution it partially transformed to troilite, with some mackinawite formation. Initiation of localized corrosion was observed in both cases. It was concluded that this was the result of a galvanic coupling between the pyrrhotite layer and the steel surface. The intensity of the observed localized corrosion varied with solution conductivity (NaCl concentration); a more conductive solution resulted in higher localized corrosion rates, consistent with the galvanic nature of the attack.

Study on Improving Stainless Steel Antibacterial Capability

2006 ◽  
Vol 510-511 ◽  
pp. 894-897
Author(s):  
Wei Hu Yang ◽  
Yu Bao Li ◽  
Lan Wu ◽  
Ai Ping Yang ◽  
Ji Dong Li ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Chemical Bond ◽  
Steel Surface ◽  
New Method ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Naoh Treatment

A new method was studied for improving stainless steel antibacterial capability. The Na2FeO4 coating was prepared on steel surface throughout NaOH treatment, then steel samples were immersed into the solution coantaining Ag+, Zn2+ and TiO2. The antibacterial-ions were fixated firmly on the stainless steel with chemical bond. Scanning electronic microscopy(SEM), X-ray(XRD) and atomic absoption spectroscopy(AAS) were employed to analyze the materials, and the results showed that the antibacterial membrane included silver citrate and silver peroxide. Quinn test was also carried out, in which Staphylococus and E.coli. the results showed that the steel has a bacteriostasis rate of 99.48% to Staphylococus, and 99.09% to E.coli.

Study on Ware Resistance of Laser Hardening Rolling Mill Liner

2011 ◽  
Vol 121-126 ◽  
pp. 3551-3554 ◽  
Author(s):  
Xing Wu Qiu ◽  
Yun Peng Zhang ◽  
Chun Ge Liu
Keyword(s):  
Laser Processing ◽  
Rolling Mill ◽  
Steel Surface ◽  
Testing Machine ◽  
Cross Flow ◽  
Wear Testing ◽  
X Ray ◽  
Technical Requirements ◽  
Laser Transformation Hardening ◽  
Single Material

In order to change the traditional status that rolling mill liner can not be manufactured with a single material, laser transformation hardening was carried out by HL-1500 cross-flow CO2 laser processing machine on 45 steel surface. developed a non-composite liner instead of the original. The microstructure and properties were researched by means of scanning electron microscopy, X-ray diffractometer, microhardness tester and abrasive wear testing machine. The result indicate that, the microstructure of laser transformation hardening layer fine and homogeneous, mainly composed of Fe, Fe3C, Fe-Cr and Cr3C2, the hardness and the relative wear resistance are about 3 times and 2.7 times as that of the substrate respectively; which can reached the technical requirements liner needed.

scholarly journals ENSURING THE EFFICIENT OPERATION OF FRICTION UNITS IN THE CONTEXT OF SELECTING FUNCTIONALLY HIGH QUALITY OILS

2021 ◽  
pp. 59-71
Author(s):  
V.I. Kyrychenko ◽  
V.V. Kyrychenko ◽  
V.P. Nezdorovin ◽  
A.I. Stremetskyi
Keyword(s):  
Phase Transformations ◽  
Surface Activity ◽  
Friction And Wear ◽  
Steel Surface ◽  
Structure And Properties ◽  
Surface Layers ◽  
Efficient Operation ◽  
X Ray ◽  
Friction Units ◽  
Steel Surfaces

The article reflects certain applied aspects of a new direction of energy — biosynthetic energy sources, such as bio-oils obtained from technical oils. In particular, there are considered results of the research of the influence of such a characteristic factor of base oils and, first of all, bio-oils as their surface activity on energy efficiency and reliability of operation of friction units lubricated by them under the conditions of the boundary regime of friction. It is proved that the surface activity of oils as an indicator of their functional quality is due to the peculiarities of the structure and properties of their molecules, the energy fields of which evoke certain tribochemical interactions with triboactivated nano-surfaces of friction steels. Separate provisions for evaluating the effect of the tribochemical activity of oils on the process of modifying the steel surfaces of functioning friction units have been formed. The essence of X-ray examination of the influence of lubricating media on the condition of the steel surface by the method of a sliding X-ray beam, analyzing the surface layers with a depth of 0.5–7 mkm. The effect of significant influence of bio-oils obtained from oils on the phase transformations of the structure and properties of the steel surface during tribe tests of samples on friction and wear is revealed. It is established that the effect of obtaining the crystal structure of steel with surface hardening under the deformed layer depends on the tribochemical activity of the proposed three lubricating compositions, which are characterized by the algorithmic growth of such activity. It is proved that the tribochemical activity of bio-oils (in compositions 2 and 3, estimated by the intensity of phase transformations in the surface layers (the effect of Rebinder PO), leads, in turn, to improved friction and wear of lubricated samples compared to the composition 1 low triboactivity. X-structural surfaces analysis of the samples of steel 45 in the initial state and after testing in the media of each of the compositions showed that in the friction processes there is a destruction of the structure of austenite with the release of α-phase (ferrite). It is shown that the intensity of such modification of steel surfaces is progressively amplified in samples lubricated with compositions in accordance with their increasing triboactivity. It was found that with the penetration into the surface layers of steel (from 0.5 to 7 mkm), lubricated with bio-oils of the samples after their tribometer tests, the amount of ferrite increases and the content of austenite decreases. This reduces the deformability of the structure of metal crystals, which leads to the strengthening of its surface under its plasticized layer, and hence the reduction of friction and wear due to the formed intersurface servito-tribopolymer film, resistant to friction. Bibl. 12, Fig. 5, Tab. 3.

In Situ Observation of Crystal Grain Orientation During Scuffing Process of Steel Surface Using Synchrotron X-ray Diffraction

2020 ◽  
Vol 68 (4) ◽  
Author(s):  
K. Yagi ◽  
T. Izumi ◽  
J. Koyamachi ◽  
S. Sanda ◽  
S. Yamaguchi ◽  
...  
Keyword(s):  
Grain Orientation ◽  
Steel Surface ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
X Ray

A MULTISCALE MODELING AND X-RAY CT EXPLORATION OF BEARING FAILURE MECHANISMS IN A COUNTERSUNK BOLTED COMPOSITE STRUCTURE

2021 ◽  
Author(s):  
XIAODONG CUI ◽  
JIAN XIAO ◽  
JIM LUA ◽  
SUPUN KARIYAWASAM ◽  
ETHAN FULGHUM ◽  
...  
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Matrix Cracking ◽  
Bearing Failure ◽  
X Ray ◽  
Failure Patterns ◽  
Modeling Approach ◽  
X Ray Computed ◽  
Bolt Diameter

To investigate the failure mechanism in composite bolted joints, an in-situ X-Ray computed tomography (XCT) technique was developed and single shear bearing (SSB) tests were performed with quasi-isotropic layup. High-fidelity XCT was explored for the detection and characterization of bearing failure in bolted composite components without removing the fastener. A novel load frame was also introduced for in-situ XCT scan and a preliminary scan was performed. A micro-macro coupling modeling approach was proposed on the basis of continuum damage mechanics (CDM) method and a static bearing model, which was based on micromechanics analysis to consider the residual stress after fiber kinking and matrix cracking under compression in the bearing region. The SSB specimens were modified using a larger bolt diameter to avoid bolt failure and achieve extensive bearing failure. The developed modeling approach was verified using SSB test data by comparing the predicted load displacement response with experimental measurement and the failure patterns obtained from XCT scanning images.

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