scholarly journals Corrosion of Copper in Unpolluted Chloride-Rich Atmospheres

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 866 ◽  
Author(s):  
Patricia Lopesino ◽  
Jenifer Alcántara ◽  
Daniel de la Fuente ◽  
Belén Chico ◽  
José Jiménez ◽  
...  
Keyword(s):  
Atmospheric Corrosion ◽  
Product Layer ◽  
Corrosion Products ◽  
X Ray Diffraction ◽  
Deposition Rates ◽  
X Ray ◽  
Corrosion Product Layer ◽  
Salinity Levels ◽  
Notable Increase ◽  
Chloride Deposition

The atmospheric corrosion of copper in pure coastal atmospheres has not been extensively studied. This paper presents the results of research carried out in pure coastal atmospheres with annual chloride deposition rates of between 110–1640 mg/m2·d. Copper specimens (99.99 wt % Cu) were exposed for 3, 6, 9, and 12 months at six testing stations located at different distances from the seashore. Tests were performed to determine the copper corrosion rate, the surface area coated with corrosion products, and the evolution of both magnitudes with exposure time. Conventional and grazing X-ray diffraction techniques were used to analyze the corrosion products formed—cuprite and the polymorphs botallackite, atacamite, and clinoatacamite—and their presence through the patina thickness, while scanning electron microscopy/energy dispersive X-ray spectrometry was employed to study the morphology of the resulting corrosion layers. The most relevant findings are a notable increase in atacamite and clinoatacamite formation at higher atmospheric salinity levels and longer exposure times, and the flaking-off of the corrosion product layer formed in the marine atmospheres with the highest chloride deposition rates.

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.

scholarly journals Program of experimental atmospheric corrosion tests of weathering steels

2015 ◽  
Vol 59 (1) ◽  
pp. 7-18
Author(s):  
V. Křivý ◽  
K. Kreislová ◽  
V. Urban ◽  
K. Vavrušová
Keyword(s):  
Atmospheric Corrosion ◽  
Corrosion Products ◽  
Experimental Program ◽  
Structural Elements ◽  
X Ray Diffraction ◽  
Corrosion Tests ◽  
X Ray ◽  
One Year ◽  
Supporting Structures

Abstract This article presents the program of experimental atmospheric corrosion test of weathering steels. This program is designed as a long-term project. Attention is paid to study of corrosion processes at different structural elements of supporting structures of bridges. Measurements of corrosion losses and average thicknesses of corrosion products are carried out within this experimental program. Protective ability of corrosion products is evaluated using X-ray diffraction analysis. The article presents results of corrosion tests after one year of exposure of corrosion specimens. It results from the tests that corrosion losses of weathering steels are signifi cantly conditioned by position and location of exposed surface within the structure.

scholarly journals Corrosion products and mechanism on NiTi shape memory alloy in physiological environment

2010 ◽  
Vol 25 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Tao Hu ◽  
Chenglin Chu ◽  
Yunchang Xin ◽  
Shuilin Wu ◽  
Kelvin W.K. Yeung ◽  
...  
Keyword(s):  
Shape Memory ◽  
Corrosion Product ◽  
Immersion Time ◽  
Product Layer ◽  
Corrosion Products ◽  
Niti Shape Memory Alloy ◽  
Nickel Concentration ◽  
Corrosion Mechanism ◽  
X Ray ◽  
Corrosion Product Layer

Despite many investigations on the corrosion behavior of NiTi shape memory alloys (SMAs) in various simulated physiological solutions by electrochemical measurements, few have reported detailed information on the corrosion products. In the present study, the structure and composition of the corrosion products on NiTi SMAs immersed in a 0.9% NaCl physiological solution are systematically investigated by scanning electron microscopy (SEM), x-ray energy dispersion spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS). It is found that attack by Cl−results in nickel being released into the solution and decrease in the local nickel concentration at the pitting sites. The remaining Ti reacts with dissolved oxygen from the solution to form titanium oxides. After long-term immersion, the corrosion product layer expands over the entire surface and XPS reveals that the layer is composed of TiO2, Ti2O3, and TiO with relatively depleted Ni. The growth rate of the corrosion product layer decreases with immersion time, and the corrosion product layer is believed to impede further corrosion and improve the biocompatibility of NiTi alloy in a physiological environment. It is found that the release rate of nickel is related to the surface structure of the corrosion product layer and immersion time. A corrosion mechanism is proposed to explain the observed results.

Corrosion Performance of TRIP Steels under Atmospheric Environment

2019 ◽  
Vol 960 ◽  
pp. 3-8
Author(s):  
Hao Xu Wang ◽  
Yi Qin Cai ◽  
Zhuang Li ◽  
Qi Zhou
Keyword(s):  
Trip Steel ◽  
Atmospheric Corrosion ◽  
Alloying Elements ◽  
Atmospheric Environment ◽  
Protective Mechanism ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trip Steels ◽  
Surface Morphologies

Atmospheric corrosion test of TRIP steels was conducted in laboratory. The surface morphologies of the specimens were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and electro-probe microanalysis (EPMA). Corrosion performance of TRIP steels under atmospheric environment was investigated by discussing the protective mechanism. The corrosion rates of steel A are significantly greater than steel B in atmospheric environment tests. The enhancement of corrosion performance of TRIP steel is attributed to the additions of alloying elements, such as P, Cr, Cu, and Ni etc.. The alloying elements increase the compactness and densification of rust layers. Electrochemical characteristic of TRIP steel is improved by means of the enhancement of the thermodynamic stability.

Corrosion Behavior of Q235A Steel under Wet-Dry Cyclic Condition

2012 ◽  
Vol 557-559 ◽  
pp. 139-142
Author(s):  
Jian Guo Liu ◽  
Yan Tao Li ◽  
Bao Rong Hou
Keyword(s):  
Electron Microscopy ◽  
Chloride Concentration ◽  
Corrosion Products ◽  
Drying Process ◽  
X Ray Diffraction ◽  
Cathodic Process ◽  
X Ray ◽  
Reduction Processes ◽  
Cyclic Condition ◽  
Scanning Electron

The corrosion processes and mechanisms of Q235A steel under wet-dry cyclic condition were studied using polarization curve compared with immersion samples, while, the corrosion morphologies and corrosion products of the steel samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The cathodic process of wet-dry samples was likely to be controlled not by the oxygen reduction, but rather by the reduction of corrosion products. During the drying process of the wet-dry sample, the electrolyte thickness decreased and chloride concentration increased. Oxygen would be much easier to diffuse into the interface of electrolyte/metal, which improved the cathodic reduction processes. Except for this, the rust itself took part in the reduction processes and hence increased the corrosion rate of the steel samples.

scholarly journals Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 591
Author(s):  
Ana Crespo ◽  
Iván Díaz ◽  
Delphine Neff ◽  
Irene Llorente ◽  
Sagrario Martínez-Ramírez ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Atmospheric Corrosion ◽  
Scientific Literature ◽  
Urban Atmosphere ◽  
Weathering Steel ◽  
X Ray Diffraction ◽  
Civil Structures ◽  
X Ray ◽  
Sulfuric Acid Treatment ◽  
Micro Raman Spectroscopy

The requirements for the formation of a protective patina on conventional weathering steels (WS) are well known in the scientific literature related to civil structures. However, these criteria are not always given due consideration when WS is used in cultural heritage, as in the case of sculptural work. An artificial patina was produced simulating artists’ working procedures using a direct patination technique, applying a solution of 10% H2SO4 on WS specimens. These were exposed for two years in the urban atmosphere of Madrid along with weathering steel specimens without artificial patina, called natural patina. The patinas generated have been analyzed using colorimetry, micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thickness measurements.The artificial patina color formed hardly differs from the color that the natural patina acquires from practically the beginning of its formation in the atmosphere of Madrid. After two years, the atmospheric corrosion rate of patinated WS is lower than 6 µm/year. The sulfuric acid treatment accelerates the protective ability of the patina with respect to the natural patina according to the ratio goethite to lepidocrocite (α/γ). Chromium-rich goethite is located in the inner part of the artificial patina as well as chromium-rich ferrihydrite. Ferrihydrite may act as a precursor of nanophasic goethite.

Synergistic effect of chloride and NO2 on the atmospheric corrosion of bronze

2009 ◽  
Vol 56 (6) ◽  
pp. 299-305 ◽  
Author(s):  
Xia Cao ◽  
Ning Wang ◽  
Ning Liu
Keyword(s):  
Synergistic Effect ◽  
Design Methodology ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
Content Type ◽  
X Ray ◽  
Corrosion Kinetics ◽  
Tension Tests

PurposeThe purpose of this paper is to investigate the effect of chloride along with NO2 on the atmospheric corrosion of bronze using exposure tests.Design/methodology/approachSurface tension tests and electrochemical impedance measurements together with scanning electron microscopy (SEM) with energy dispersive atomic X‐ray, and X‐ray diffraction are used to characterize the corrosion behavior.FindingsThe results of the weight loss measurements show that the whole corrosion kinetics can be described approximately by: ΔW=atb; the synergistic effect of chloride and NO2 is observed clearly, though no nitrate existed in the corrosion products.Originality/valueA new catalyst theory has been suggested in this paper, i.e. that NO2 acts as a catalyst during the corrosion process when significant quantities of chloride also are present.

Particularities of indoor atmospheric corrosion of steel inside electric boxes in the tropical climate of Tabasco, Mexico

2020 ◽  
pp. 1420326X2095041
Author(s):  
Ebelia Del Angel-Meraz ◽  
Francisco Corvo ◽  
Nancy E. Hernandez-Morales ◽  
Maria C. Tejero-Rivas
Keyword(s):  
Atmospheric Corrosion ◽  
Tropical Climate ◽  
Corrosion Products ◽  
Rural Site ◽  
Sulphur Compounds ◽  
Coastal Site ◽  
The Difference ◽  
Corrosion Of Steel ◽  
Chloride Deposition ◽  
Exposure Conditions

Indoor corrosion inside electric boxes is important for the reliability of electric and electronic instruments. A parallel evaluation of indoor/outdoor atmospheric corrosion of steel, pollutants and meteorological parameters was made at two sites, i.e. a rural site and a coastal site of the Tabasco State, Mexico. Two exposure conditions were evaluated: outdoors and inside electric boxes. Very low levels of sulphur compounds have been observed at the two exposure sites and two exposure conditions. As expected, corrosion of steel in an open atmosphere is higher than indoors (electric boxes). The difference between corrosion outdoors and inside electric boxes is higher at the coastal site due to the influence of chloride deposition. Significant differences have been observed in the morphology of corrosion products formed on steel. The influence of sun radiation, rain, dew and fog causes the formation of more compact corrosion products. The influence of Time of Wetness outdoors is in some extent equivalent to the influence of relative humidity inside electric boxes. Commonly, chloride deposition is very low indoors, showing low influence on corrosion. However, in particular conditions of Tabasco coastal tropical climate, its role is significant indoors. Reliability of electric and electronic instruments could be affected.

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