scholarly journals Investigation of Barkhausen Noise Emission in Steel Wires Subjected to Different Surface Treatments

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 912
Author(s):  
Lukáš Krkoška ◽  
Martin Moravčík ◽  
Katarína Zgútová ◽  
Miroslav Neslušan ◽  
Milan Uhričík ◽  
...  

Steel rope wires represent the main bearing components of bridges whose long-term operation depends on loading conditions, corrosion attack, and/or pre-stressing. Corrosion attack especially can remarkably reduce the effective cross-sectional area, which in turn over-stresses the wires and redistributes stress to the neighboring wires. The premature collapse of many bridges is very often caused by wire rupture as a result of their poor corrosion protection. For these reasons, various processes—such as galvanizing, phosphating, etc.—have been applied to steel wires to increase their resistance against corrosion. However, these processes can alter the microstructure, especially in the near-surface regions. The Barkhausen noise technique has been already reported as a suitable technique for investigating corrosion extent and true pre-stress in the steel rope wires. This study reports that non-homogeneity of the surface state of wires undergoing different surface treatment makes it more difficult to assess the true stress state and increase the uncertainty of Barkhausen noise measurement. Barkhausen noise signals are correlated with metallographic and SEM observations as well as microhardness measurements. The non-homogeneity of the surface state of wires is also investigated by the use of chemical mapping and linear chemical analyses.

2020 ◽  
Vol 513 ◽  
pp. 167134
Author(s):  
M. Neslušan ◽  
F. Bahleda ◽  
K. Trojan ◽  
M. Pitoňák ◽  
K. Zgútová

2021 ◽  
Vol 11 (22) ◽  
pp. 10646
Author(s):  
Filip Pastorek ◽  
Martin Decký ◽  
Miroslav Neslušan ◽  
Martin Pitoňák

This study deals with corrosion damage of low alloyed feritic steels of variable strength. Three different steels of nominal yield strength 235, 700 and 1100 MPa were subjected to the variable degree of corrosion attack developed in the corrosion chamber under a neutral salt spray (NSS) atmosphere. The corrosion damage was investigated by the use of conventional metallographic observations when the thickness of corroded layer was quantified. Moreover, non-destructive magnetic technique, based on Barkhausen noise, was also employed. It was found that the rate of corrosion damage decreases along with the increasing number of days in the chamber. The similar evolution can be also found for Barkhausen noise emission and the extracted parameters from the emission. It can be reported that conventional rms value of Barkhausen noise signal as well as FWHM (full width at half maximum of Barkhausen noise envelope) can be linked with the corrosion extent, especially in the early phases of corrosion attack. The PP (peak position of Barkhausen noise envelope) values exhibit poor sensitivity.


2019 ◽  
Vol 484 ◽  
pp. 179-187 ◽  
Author(s):  
M. Neslušan ◽  
F. Bahleda ◽  
P. Minárik ◽  
K. Zgútová ◽  
M. Jambor

Author(s):  
R.C. Dickenson ◽  
K.R. Lawless

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.


Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.


2016 ◽  
Vol 23 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Dunja Perić ◽  
Paul A. Bartley ◽  
Lawrence Davis ◽  
Ali Ulvi Uzer ◽  
Cahit Gürer

AbstractLignin is a coproduct of biofuel and paper industries, which exhibits binding qualities when mixed with water. Lignin is an ideal candidate for a sustainable stabilization of unpaved roads. To this end, an experimental program was devised and carried out to quantify effects of lignin on compaction and early age shear strength behaviors of sand. Samples were prepared by mixing a particular type of coproduct called calcium lignosulfonate (CaL) with sand and water. Based on the extensive analyses of six series of strength tests, it was found that a normalized cohesion increased with an increasing normalized areas ratio. Normalizations were carried out by dividing the cohesion and area ratio by gravimetric CaL content whereby the area ratio was obtained by dividing the portion of the cross-sectional area occupied with lignosulfonate-water (CaL-W) paste by the total cross-sectional area. While the increase in the normalized cohesion eventually leveled out, the cohesion peaked at 6% of CaL. Thus, sand-CaL-water (S-CaL-W) mixes sustained larger shear stresses than dry sand for a range of normal stresses below the limiting normal stress. Consequently, the early age behavior indicates that adding CaL-W to sand is clearly beneficial in the near-surface applications in dry sand.


1994 ◽  
Vol 357 ◽  
Author(s):  
A. J. Pedraza ◽  
Siqi Cao ◽  
L. F. Allard ◽  
D. H. Lowndes

AbstractA near-surface thin layer is melted when single crystal alumina (sapphire) is pulsed laserirradiated in an Ar-4%H2 atmosphere. γ-alumina grows epitaxially from the (0001) face of axalumina (sapphire) during the rapid solidification of this layer that occurs once the laser pulse is over. Cross sectional high resolution transmission electron microscopy (HRTEM) reveals that the interface between unmelted sapphire and γ-alumina is atomistically flat with steps of one to a few close-packed oxygen layers; however, pronounced lattice distortions exist in the resolidified γ-alumina. HRTEM also is used to study the metal-ceramic interface of a copper film deposited on a laser-irradiated alumina substrate. The observed changes of the interfacial structure relative to that of unexposed substrates are correlated with the strong enhancement of film-substrate bonding promoted by laser irradiation. HRTEM shows that a thin amorphous film is produced after irradiation of 99.6% polycrystalline alumina. Formation of a diffuse interface and atomic rearrangements that can take place in metastable phases contribute to enhance the bonding strength of copper to laser-irradiated alumina.


2002 ◽  
Vol 743 ◽  
Author(s):  
Hideki Hasegawa ◽  
Tamotsu Hashizume

ABSTRACTThis paper reviews the authors′ recent efforts to clarify the properties of electronic states near surfaces of GaN and AlGaN by using variousin-situandex-situcharacterization techniques, including UHV contact-less C-V, photoluminescence surface state spectroscopy (PLS3), cathode luminescence in-depth spectroscopy (CLIS),and gateless FET techniques that have been developed by the authors’ group.As a result, a model including a U-shaped surface state continuum, having a particular charge neutrality level, combined with frequent appearance of near-surface N-vacancy related deep donor states having a discrete level at Ec - 0.37eV is proposed as a unified model that can explain large gate leakage currents and current collapse in AlGaN/GaN HFETs. Hydrogen plasma treatment and SiO2deposition increase N-vacancy related deep donors. Reasonably good surface passivation can be achieved by ECR-plasma SiNx films and by ECR-plasma oxidized Al2O3films both combined with ECR N2plasma treatment.


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