Corrosion Damage Research of Stayed Cable Under Coupling Salt Spray Environment and Loading

2016 ◽  
pp. 2240-2246
Author(s):  
Y. Guowen ◽  
D. Guojun ◽  
L. Shiya
Keyword(s):  
Salt Spray ◽  
Corrosion Damage

Effect of Black Plate on Growth Action and Corrosion Resistance of Sn-Fe Alloy Film

2011 ◽  
Vol 121-126 ◽  
pp. 100-104
Author(s):  
Jian Zhong Li ◽  
Yan Wen Tian ◽  
Ying Li ◽  
Yu Cheng Wang
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Alloy Film ◽  
Void Space ◽  
Alloy Films ◽  
Fe Alloys ◽  
Black Plate ◽  
Annealing Mode ◽  
Better Than

Effect of black plate on growth action and corrosion resistance of Sn-Fe alloy film was investigated by means of metallurgical microscope, scanning electron microscopy (SEM), salt spray corrosion test and electrochemistry methods. The results show that the different modes of annealing and rolling have a remarkably effects on the surface morphology and grain size of Sn-Fe alloys. Crystalline grain of Sn-Fe alloy film for T4-CA or T2.5-BA is relatively continues, homogeneous and denser, but that for DR materials exists obviously surface inhomogeneity sizes and even void space of interweave. Rust spot easily generate on discontinuous alloy films or void space of interweave growth and gradually cover on the surface of Sn-Fe alloy films without corrosion damage. Corrosion resistance of BA materials is better than that of CA materials. Under the same annealing mode, corrosion resistance of DR materials is worse.

Study of Corrosion Damage Under Protective Coatings

2001 ◽  
Author(s):  
Mohammad Khobaib ◽  
Jochen Hoffmann ◽  
Shamachary Sathish ◽  
Michael S. Donley
Keyword(s):  
Spatial Resolution ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Salt Spray ◽  
Electrochemical Techniques ◽  
Corrosion Damage ◽  
Acoustic Microscopy ◽  
Localized Corrosion ◽  
Corrosion Activity ◽  
Military Aircraft

Abstract Polymer coatings provide an excellent corrosion barrier for Al-skinned military aircraft. However, the degradation and damage of the coatings in their service life over time leads to the initiation of corrosion damage at the substrate level. Early detection and negation of such activity can provide extensive cost savings. Several Electrochemical techniques and Non Destructive Evaluation (NDE) show promise in detecting the onset of corrosion under such coatings. Current accelerated testing of aircraft coating systems for corrosion protection relies heavily on salt spray methods. Electrochemical techniques such as Electrochemical Impedance Spectroscopy (EIS) and Electrochemical Noise Methods (ENM) provide insight into the global properties of a coating system, and both techniques are being used on a limited basis. However, there is a need to investigate corrosion events with greater spatial resolution under coatings at the metal/coating interface. Such corrosion activity may be related to coating defects and variations in the surface chemistry of the underlying metal. The Scanning Vibrating Electrode Technique (SVET) has been developed to allow the investigation of localized corrosion activity with high spatial resolution. Such activity may be associated with coating defects or galvanic coupled regions of the metal surface. Electrochemical and NDE techniques were used to investigate the early stage of corrosion activity under protective coatings. Coatings in this investigation ranged from a simple epoxy amine to commercially used military aircraft polyurethane coatings. SVET testing of panels with intact high-resistance barrier coatings could not reveal corrosion damage under normal testing conditions because of little or no corrosion activity within the limited exposure time. Chemical, mechanical, and electrochemical means of accelerating the corrosion damage were utilized to obtain results in a reasonable time frame. Corrosion initiation and its progress under the coating were studied in detail and the results are discussed here. Complimentary high-resolution NDE techniques, such as Scanning Acoustic Microscopy (SAM) and Fan Thermography measurements were used to identify the corrosion sites. The overall objective of this investigation is to establish a correlation between the electrochemical and NDE techniques.

scholarly journals Effect of Carbon Nanotubes on Chloride Penetration in Cement Mortars

2019 ◽  
Vol 9 (5) ◽  
pp. 1032 ◽  
Author(s):  
Panagiota Dalla ◽  
Ilias Tragazikis ◽  
Dimitrios Exarchos ◽  
Konstantinos Dassios ◽  
Nektaria Barkoula ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Mechanical Performance ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Surface Conductivity ◽  
Chloride Penetration ◽  
Accelerated Corrosion ◽  
Compressive Response ◽  
Cement Mortars

The study investigates the effect of carbon nanotubes on chloride penetration in nano-modified mortars and reports on the physical, electrical, and mechanical performance of the material. Mortars were artificially corroded and their surface electrical surface conductivity as well as flexural and compressive strength were measured. The influence of variable nanotube concentration in accelerated corrosion damage was evaluated. Nanotube concentration was found to significantly affect the permeability of the mortars; improvements in flexural and compressive response of mortars exposed to salt spray fog, compared to virgin specimens, were rationalized upon decreases in the apparent porosity of the materials due to filling of the pores with sodium chloride. Electrical resistivity was found to increase up to two orders of magnitude with respect to the surface value; above the percolation threshold, the property impressively increased up to five orders of magnitude.

scholarly journals Usage of Barkhausen Noise for Assessment of Corrosion Damage on Different Low Alloyed Steels

2021 ◽  
Vol 11 (22) ◽  
pp. 10646
Author(s):  
Filip Pastorek ◽  
Martin Decký ◽  
Miroslav Neslušan ◽  
Martin Pitoňák
Keyword(s):  
Salt Spray ◽  
Corrosion Damage ◽  
Noise Signal ◽  
Peak Position ◽  
Barkhausen Noise ◽  
Variable Degree ◽  
Neutral Salt ◽  
Noise Emission ◽  
Corrosion Attack ◽  
Non Destructive

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.

CORROSION RESISTANCE OF THE BRAZED JOINTS OF THE GTE FUEL MANIFOLDS, MADE WITH VARIOUS BRAZING ALLOYS

2021 ◽  
pp. 23-33
Author(s):  
A.V. Sviridov ◽  
◽  
A.N. Afanasyev-Khodykin ◽  
I.A. Galushka ◽  
◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Gas Turbine ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Spray Chamber ◽  
Corrosion Resistant ◽  
Research Results ◽  
Brazed Joints

Presents the results of work on assessing the corrosion resistance of brazed joints of corrosion-resistant steels used in the manufacture of fuel manifolds for gas turbine engines in a salt spray chamber. The main types of corrosion damage of brazed joints made with brazing alloys of various types (based on copper and nickel) have been identified. The influence of the type of brazing alloy and the grade of the brazed materials on the nature of corrosion damage to brazed joints is determined. Based on the research results, assumptions have been made about the mechanism of occurrence and development of corrosion damage in brazed joints of various materials.

scholarly journals Microstructure and Corrosion Resistance of Zn-Al Diffusion Layer on 45 Steel Aided by Mechanical Energy

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3032 ◽  
Author(s):  
Jianbin Tong ◽  
Yi Liang ◽  
Shicheng Wei ◽  
Hongyi Su ◽  
Bo Wang ◽  
...  
Keyword(s):  
Diffusion Layer ◽  
Mechanical Energy ◽  
Salt Spray ◽  
Steel Structures ◽  
Corrosion Damage ◽  
Immersion Test ◽  
Corrosion Products ◽  
Diffusion Method ◽  
Electrochemical Test ◽  
Before And After

In harsh environments, the corrosion damage of steel structures and equipment is a serious threat to the operational safety of service. In this paper, a Zn-Al diffusion layer was fabricated on 45 steel by the Mechanical Energy Aided Diffusion Method (MEADM) at 450 °C. The microstructure and composition, the surface topography, and the electrochemical performance of the Zn-Al diffusion layer were analyzed before and after corrosion. The results show that the Zn-Al diffusion layer are composed of Al2O3 and Γ1 phase (Fe11Zn40) and δ1 phase (FeZn6.67, FeZn8.87, and FeZn10.98) Zn-Fe alloy. There is a transition zone with the thickness of about 5 μm at the interface between the Zn-Al diffusion layer and the substrate, and a carbon-rich layer exists in this zone. The full immersion test and electrochemical test show that the compact corrosion products produced by the initial corrosion of the Zn-Al diffusion layer will firmly bond to the Zn-Al diffusion layer surface and fill the crack, which plays a role in preventing corrosion of the corrosive medium and reducing the corrosion rate of the Zn-Al diffusion layer. The salt spray test reveals that the initial corrosion products of the Zn-Al diffusion layer are mainly ZnO and Zn5(OH)8Cl2H2O. New corrosion products such as ZnAl2O4, FeOCl appear at the middle corrosion stage. The corrosion product ZnAl2O4 disappears, and the corrosion products Zn(OH)2 and Al(OH)3 appear at the later corrosion stage.

scholarly journals Corrosion Damage Mechanism of TiN/ZrN Nanoscale Multilayer Anti-Erosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 400 ◽  
Author(s):  
Mingrui Geng ◽  
Guangyu He ◽  
Zhiping Sun ◽  
Jiao Chen ◽  
Zhufang Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Hot Corrosion ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Damage Mechanism ◽  
Element Distribution ◽  
Salt Spray Corrosion ◽  
Corrosion Tests ◽  
Engine Compressor ◽  
Aero Engines

TiN/ZrN multilayers can effectively improve the erosion resistance of metals, particularly titanium alloys employed in aero engines. To explore the corrosion damage mechanism of TiN/ZrN nanoscale multilayers (nanolaminate), a novel [TiN/ZrN]100 nanolaminate coating was deposited on Ti-6Al-4V alloys by multi-arc ion plating method. Salt spray corrosion tests and hot corrosion experiment were carried out to evaluate the corrosion resistance of the coating. The corrosion and damage mechanisms were explored with the help of detailed microstructure, phase composition and element distribution characterizations. The salt spray corrosion tests showed that the [TiN/ZrN]100 nanolaminate coating possessed good corrosion resistance, which protected substrate against the corrosion. The low temperature hot corrosion tests showed that the oxidation occurred on the surface of the coating, which improved the oxidation resistance of the sample. However, the oxidized droplets squeezed the coating, and destroyed the oxidized layers. As a result, the coating was peeled off from the substrate. The research highlights the corrosion resistance of the novel TiN/ZrN nanolaminate coating and offers a support for their application in engine compressor blade.

scholarly journals Corrosion Behavior of Laser Interference Structured Al 2024 Coated with a Chromate-containing Epoxy Primer

CORROSION ◽  
10.5006/3717 ◽  
2021 ◽  
Author(s):  
Jiheon Jun ◽  
Adrian Sabau ◽  
Michael Stephens
Keyword(s):  
Corrosion Behavior ◽  
Laser Fluence ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Nanosecond Laser ◽  
Type I ◽  
Preparation Technique ◽  
Laser Interference ◽  
Chemical Cleaning ◽  
Epoxy Primer

In this study, corrosion behavior of laser-interference treated Al20204-T3 specimens, which were coated with a primer, is presented. The surface of as-received Al2024-T3 specimens were laser-interference structured by splitting the primary beam of a Q-switched Nd:YAG pulsed nanosecond laser into two beams and focusing them to the same spot on the specimen surface. After being stored in plastic cases for up to 70 days, without any additional cleaning, the specimens were spray painted with a chromate-containing epoxy primer, CA7233, compliant to MIL-PRF-23377 Type I Class C2 specification. The corrosion behavior of laser-interference specimens was assessed against that of specimens prepared by chromated conversion coating and sulfuric acid anodizing treatments. After the ASTM B117 corrosion exposure, it was found that the laser processed specimens exhibited only few blisters. On one hand, most specimens prepared at a laser fluence of 1.78 J/cm2, without any additional chemical cleaning, were found to develop one very small blister after only 96 h of exposure. However, the growth of these blisters was not significant even after 1000 h of salt spray exposure. On the other hand, only a fraction of the specimens prepared at a laser fluence of 1.24 J/cm2 and acetone wiped right after the laser structuring, were found to develop several tiny blisters after 790 h and longer exposure. Overall, it was found that the corrosion damage was minimized at a laser rastering speed of 4 mm/s, condition for which only 33% of specimens developed very minor corrosion damage. The ASTM D1654 creepage ratings, which was used to evaluate the corrosion damage along the scribe lines, were found to be at least nine for all coated panels. These results indicate that the laser-interference technique with the additional acetone wiping has the potential to be further developed as a non-chemical surface preparation technique for chromate-containing epoxy primers coating systems.

Improved Atmospheric Corrosion Testing for Aluminum Alloys, Part I: Deconstructing ASTM G85-A2

CORROSION ◽  
10.5006/3334 ◽  
2019 ◽  
Vol 76 (1) ◽  
pp. 39-50
Author(s):  
Mary E. Parker ◽  
Robert G. Kelly
Keyword(s):  
Aluminum Alloys ◽  
Relative Humidity ◽  
Corrosion Rate ◽  
Atmospheric Corrosion ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Spray Chamber ◽  
Testing Environment ◽  
Dry Air ◽  
Dwell Period

In this work, the testing environment generated during ASTM G85-A2 exposure was deconstructed for two different commercial salt spray chambers. It was found that relative humidity (RH) control was critical to obtaining consistent results among different salt spray chamber designs, and seemingly small differences in chamber operation could have a significant impact on RH and associated corrosion damage. When RH was too high during the dwell period of the wet-dry cycle, rinsing of the sample prevented the accumulation of corrosion products along grain boundaries, which was necessary for exfoliation formation. When RH during the dwell period was too low, local anodes stifled during the dry air purge and corrosion rate was very low for most of the repeating 6 hour cycle. This work was the first in a two part study.

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