Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

NASA Astrophysics Data System (ADS)

Solehudin, Agus; Nurdin, Isdiriayani

2014-03-01

Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

The Corrosion of High Performance Steel in Adverse Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Desmond C.

The corrosion products that have formed on weathering steel bridges exposed to different weather conditions in the United States have been evaluated. They have been analyzed by spectroscopic techniques to determine the relationship between protective and non-protective rust coatings, and their relationship to the exposure conditions. Bridges constructed recently using High Performance Steel, as well as older bridges built with Type A588B weathering steel, were evaluated for corrosion performance of the rust coatings. In locations where the steel is subjected to regular wet-dry cycling, where the surface is wet for less than about 20% of the time, a protective patinamore » starts to form after a few months exposure, and continues to an adherent, impervious coating after a decade. The protective patina is characterized by the formation of only goethite and lepidocrocite. The goethite makes up about 80% of the rust, and itself consists of a nanophase component, < 15 nm, making up about 70% of the goethite. The nanophase goethite is basically undetected by X-ray diffraction. In the presence of high time-of-wetness, >40%, or infrequent drying cycles (regions close to waterways, fog or having high humidity), the weathering steel forms a rust coating that consists of a large amount of maghemite, and goethite that contains very little of the nanophase component. The rust coating ex-foliates from the steel and is not protective. Under exposure conditions in which chlorides are deposited onto the weathering steel surface (marine or de-icing salt locations), the protective patina also does not form. Instead, the rust coating consists of a large fraction of akaganeite that forms at the expense of the lepidocrocite and nanophase goethite. The bridges exposed to high chloride concentrations, 1.5 wt%, and therefore having no protective patina, have corrosion rates measured to be 6 times larger than expected for weathering steel with the protective patina.« less

Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

NASA Astrophysics Data System (ADS)

Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin; Othman, Norinsan Kamil

2014-09-01

Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm. Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

PubMed

Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

2013-01-01

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01).

Atmospheric Corrosion Behavior and Mechanism of a Ni-Advanced Weathering Steel in Simulated Tropical Marine Environment

NASA Astrophysics Data System (ADS)

Wu, Wei; Zeng, Zhongping; Cheng, Xuequn; Li, Xiaogang; Liu, Bo

2017-12-01

Corrosion behavior of Ni-advanced weathering steel, as well as carbon steel and conventional weathering steel, in a simulated tropical marine atmosphere was studied by field exposure and indoor simulation tests. Meanwhile, morphology and composition of corrosion products formed on the exposed steels were surveyed through scanning electron microscopy, energy-dispersive x-ray spectroscopy and x-ray diffraction. Results indicated that the additive Ni in weathering steel played an important role during the corrosion process, which took part in the formation of corrosion products, enriched in the inner rust layer and promoted the transformation from loose γ-FeOOH to dense α-FeOOH. As a result, the main aggressive ion, i.e., Cl-, was effectively separated in the outer rust layer which leads to the lowest corrosion rate among these tested steels. Thus, the resistance of Ni-advanced weathering steel to atmospheric corrosion was significantly improved in a simulated tropical marine environment.

Corrosion behavior of low alloy steels in a wet-dry acid humid environment

NASA Astrophysics Data System (ADS)

Zhao, Qing-he; Liu, Wei; Yang, Jian-wei; Zhu, Yi-chun; Zhang, Bin-li; Lu, Min-xu

2016-09-01

The corrosion behavior of corrosion resistant steel (CRS) in a simulated wet-dry acid humid environment was investigated and compared with carbon steel (CS) using corrosion loss, polarization curves, X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), N2 adsorption, and X-ray photoelectron spectroscopy (XPS). The results show that the corrosion kinetics of both steels were closely related to the composition and compactness of the rust, and the electrochemical properties of rusted steel. Small amounts of Cu, Cr, and Ni in CRS increased the amount of amorphous phases and decreased the content of γ-FeOOH in the rust, resulting in higher compactness and electrochemical stability of the CRS rust. The elements Cu, Cr, and Ni were uniformly distributed in the CRS rust and formed CuFeO2, Cu2O, CrOOH, NiFe2O4, and Ni2O3, which enhanced the corrosion resistance of CRS in the wet-dry acid humid environment.

Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin

Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm.more » Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.« less

Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solehudin, Agus, E-mail: asolehudin@upi.edu; Nurdin, Isdiriayani

2014-03-24

Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H{sub 2}S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAHmore » concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.« less

Corrosion behavior of 2205 duplex stainless steel.

PubMed

Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

1997-07-01

The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

Hot-corrosion of AISI 1020 steel in a molten NaCl/Na2SO4 eutectic at 700°C

NASA Astrophysics Data System (ADS)

Badaruddin, Mohammad; Risano, Ahmad Yudi Eka; Wardono, Herry; Asmi, Dwi

2017-01-01

Hot-corrosion behavior and morphological development of AISI 1020 steel with 2 mg cm-2 mixtures of various NaCl/Na2SO4 ratios at 700°C were investigated by means of weight gain measurements, Optical Microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The weight gain kinetics of the steel with mixtures of salt deposits display a rapid growth rates, compared with the weight gain kinetics of AISI 1020 steel without salt deposit in dry air oxidation, and follow a steady-state parabolic law for 49 h. Chloridation and sulfidation produced by a molten NaCl/Na2SO4 on the steel induced hot-corrosion mechanism attack, and are responsible for the formation of thicker scale. The most severe corrosion takes place with the 70 wt.% NaCl mixtures in Na2SO4. The typical Fe2O3 whisker growth in outer part scale was attributed to the FeCl3 volatilization. The formation of FeS in the innermost scale is more pronounced as the content of Na2SO4 in the mixture is increased.

Fracture-Toughness Analysis in Transition-Temperature Region of Three American Petroleum Institute X70 and X80 Pipeline Steels

NASA Astrophysics Data System (ADS)

Shin, Sang Yong; Woo, Kuk Je; Hwang, Byoungchul; Kim, Sangho; Lee, Sunghak

2009-04-01

The fracture toughness in the transition-temperature region of three American Petroleum Institute (API) X70 and X80 pipeline steels was analyzed in accordance with the American Society for Testing and Materials (ASTM) E1921-05 standard test method. The elastic-plastic cleavage fracture toughness ( K Jc ) was determined by three-point bend tests, using precracked Charpy V-notch (PCVN) specimens; the measured K Jc values were then interpreted by the three-parameter Weibull distribution. The fracture-toughness test results indicated that the master curve and the 98 pct confidence curves explained the variation in the measured fracture toughness well. The reference temperatures obtained from the fracture-toughness test and index temperatures obtained from the Charpy impact test were lowest in the X70 steel rolled in the two-phase region, because this steel had smaller effective grains and the lowest volume fraction of hard phases. In this steel, few hard phases led to a higher resistance to cleavage crack initiation, and the smaller effective grain size led to a higher possibility of crack arrest, thereby resulting in the best overall fracture properties. Measured reference temperatures were then comparatively analyzed with the index temperatures obtained from the Charpy impact test, and the effects of microstructures on these temperatures were discussed.

Resistance to Corrosion of Zirconia Coatings Deposited by Spray Pyrolysis in Nitrided Steel

NASA Astrophysics Data System (ADS)

Cubillos, G. I.; Olaya, J. J.; Bethencourt, M.; Cifredo, G.; Blanco, G.

2013-10-01

Coatings of zirconium oxide were deposited onto three types of stainless steel, AISI 316L, 2205, and tool steel AISI D2, using the ultrasonic spray pyrolysis method. The effect of the flux ratio on the process and its influence on the structure and morphology of the coatings were investigated. The coatings obtained, 600 nm thick, were characterized using x-ray diffraction, scanning electron microscopy, confocal microscopy, and atomic force microscopy. The resistance to corrosion of the coatings deposited over steel (not nitrided) and stainless steel nitrided (for 2 h at 823 K) in an ammonia atmosphere was evaluated. The zirconia coating enhances the stainless steel's resistance to corrosion, with the greatest increase in corrosion resistance being observed for tool steel. When the deposition is performed on previously nitrided stainless steel, the morphology of the surface improves and the coating is more homogeneous, which leads to an improved corrosion resistance.

Control of microbiological corrosion on carbon steel with sodium hypochlorite and biopolymer.

PubMed

Oliveira, Sara H; Lima, Maria Alice G A; França, Francisca P; Vieira, Magda R S; Silva, Pulkra; Urtiga Filho, Severino L

2016-07-01

In the present work, the interaction of a mixture of a biocide, sodium hypochlorite (NaClO), and a biopolymer, xanthan, with carbon steel coupons exposed to seawater in a turbulent flow regime was studied. The cell concentrations, corrosion rates, biomasses, and exopolysaccharides (EPSs) produced on the coupon surfaces with the various treatments were quantified. The corrosion products were evaluated using X-ray diffraction (XRD), and the surfaces of steels were analysed by scanning electron microscopy (SEM). The results indicated that xanthan and the hypochlorite-xanthan mixture reduced the corrosion rate of steel. Copyright © 2016. Published by Elsevier B.V.

Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

PubMed Central

Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng

2016-01-01

The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328

A comparative study on the electrochemical corrosion behavior of iron and X-65 steel in 4.0 wt % sodium chloride solution after different exposure intervals.

PubMed

Sherif, El-Sayed M

2014-07-09

In this work, the results obtained from studying the anodic dissolution of pure iron and API X-65 5L pipeline steel after 40 min and 12 h exposure period in 4.0 wt % NaCl solutions at room temperature were reported. Potential-time, electrochemical impedance spectroscopy, potentiodynamic polarization, and chronoamperometric current-time at constant potential techniques were employed. It has been found that the iron electrode corrodes in the chloride test solutions faster than the API X-65 5L steel does under the same conditions. Increasing the exposure period for the electrodes from 40 min to 12 h showed a significant reduction in the corrosion parameters for both iron and steel in the 4.0 wt % NaCl solution. Results together confirmed clearly that the X-65 steel is superior to iron against corrosion in sodium chloride solutions.

Development of New Type Seawater Resistant Steel and the Research of Its Structure and Corrosion Resistance

NASA Astrophysics Data System (ADS)

Yin, Baoliang; Yin, Shaojiang; Liu, Zhiyong; Wang, Yunge; Yu, Hao; Li, Haixu; Zhou, Tao

This paper investigated two kinds of corrosion resistant low alloy steels depending on the environment of the North China see (Steel S) and South China sea (Steel N), respectively. The mechanical and corrosion properties of the two steels were analyzed in this paper. Tin was added into both steels to improve the corrosion resistance. Structure and mechanical properties of the two steels were detected, and the results revealed that the microstructures of both steels were ferrite and little divorced pearlite. The yield strength and impact toughness at -40°C of the steel S are 423MPa and 98 J, respectively. The yield strength and impact toughness at -40°C of the steel N are 437 MPa and 70 J, respectively. The properties mentioned above met or even exceeded the requirement (yield strength 355 MPa, toughness 34 J) in these areas. The corrosion resistant properties of the two steels were also investigated via the means of immersion test and electrochemical experiment. The immersion test indicated that the corrosion rate of steel S and steel N was 0.00938 mg/h·cm2 and 0.00838 mg/h·cm2, respectively, when completely immersed for 168 hours, and the corrosion rate was much lower than that of E36. The Electrochemical experiments showed that the corrosion potential (Ecorr) of both steels was higher in contrast to E36, which indicated a lower corrosion trend.

Atmospheric corrosion performance of different steels in early exposure in the coastal area region West Java, Indonesia

NASA Astrophysics Data System (ADS)

Nuraini, Lutviasari; Prifiharni, Siska; Priyotomo, Gadang; Sundjono, Gunawan, Hadi; Purawiardi, Ibrahim

2018-05-01

The performance of carbon steel, galvanized steel and aluminium after one month exposed in the atmospheric coastal area, which is in Limbangan and Karangsong Beach, West Java, Indonesia was evaluated. The corrosion rate was determined by weight loss method and the morphology of the steel after exposed was observed by Scanning Electron Microscopy(SEM)/Energy Dispersive X-Ray Analysis(EDX). The site was monitored to determine the chloride content in the marine atmosphere. Then, the corrosion products formed at carbon steel were characterized by X-Ray diffraction (XRD). The result showed the aggressively corrosion in Karangsong beach, indicated from the corrosion rate of carbon steel, galvanized steel and aluminium were 38.514 mpy; 4.7860 mpy and 0.5181 mpy, respectively. While in Limbangan Beach the corrosion rate of specimen carbon steel, galvanized steel and aluminium were 3.339; 0.219 and 0.166 mpy, respectively. The chloride content was found to be the main factor that influences in the atmospheric corrosion process in this area. Chloride content accumulated in Karangsong and Limbangan was 497 mg/m2.day and 117 mg/m2.day, respectively. The XRD Analysis on each carbon steel led to the characterization of a complex mixture of iron oxides phases.

Corrosion resistance of high-Cr oxide dispersion strengthened ferritic steels in super-critical pressurized water

NASA Astrophysics Data System (ADS)

Cho, H. S.; Kimura, A.

2007-08-01

The effects of alloying elements, such as Cr and Al, on corrosion resistance in super critical pressurized water (SCPW) have been investigated to develop corrosion resistant oxide-dispersion-strengthened (ODS) steels. Corrosion tests were performed in a SCPW (783 K, 25 MPa) environment. Weight gain was measured after exposure to the SCPW, and then oxide layers were analyzed by low angle X-ray diffraction and SEM microscopy. The weight gains of all high-Cr ODS steels are smaller than an austenitic stainless steel (SUS316L). More uniform and thinner oxidation layers were observed on the ODS steels after corrosion compared to those on 9Cr martensitic steel and SUS316L.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review.

PubMed

Dwivedi, D; Lepkova, K; Becker, T

2017-03-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review

NASA Astrophysics Data System (ADS)

Dwivedi, D.; Lepkova, K.; Becker, T.

2017-03-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review

PubMed Central

Dwivedi, D.; Becker, T.

2017-01-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed. PMID:28413351

Relationship Between pH and Electrochemical Corrosion Behavior of Thermal-Sprayed Ni-Al-Coated Q235 Steel in Simulated Soil Solutions

NASA Astrophysics Data System (ADS)

Wei, Wei; Wu, Xin-qiang; Ke, Wei; Xu, Song; Feng, Bing; Hu, Bo-tao

2017-09-01

Electrochemical corrosion behavior of a thermal-sprayed Ni-Al-coated Q235 steel was investigated in the simulated soil solutions at different pH values using measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy as well as surface analyses including x-ray diffraction analysis, scanning electron microscope equipped with an energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The results showed that the corrosion resistance of the Ni-Al-coated Q235 steel was dependent on the pH of the test solution. From pH = 3.53 to pH = 4.79, the corrosion resistance of the coated steel increased rapidly. In the pH range from 4.79 to 12.26, the corrosion resistance exhibited no significant change. At pH 13.25, the corrosion resistance of the sample was found to decrease. The calculated corrosion rate of Ni-Al-coated Q235 steel was lower than that of the uncoated Q235 steel and galvanized steel in all the test solutions. Over a wide range of pH values, the Ni-Al-coated Q235 steel exhibited extremely good corrosion resistance. The experimental data together with the potential-pH diagrams provided a basis for a detailed discussion of the related corrosion mechanisms of the coated steel.

A SURVEY OF THE CORROSION OF MARTENSITIC AND FERRITIC STAINLESS STEELS IN PRESSURIZED WATER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaver, R.J.; Leitten, C.F. Jr.

1963-07-16

>The corrosion resistance of mantensitic and ferritic austenitic stainless steels and carbon steels in pressurized water at 500 to 600 deg F is compared. Included are specific out-of-pile data for austenitic stainless steels, AISI types types 410, 420, 431, and 440C; the ferritic AISI types 430, 442, and 446; the precipitation-hardening type 17-4PH; and carbon steels, ASTM 212 A and B. Available corrosion results obtained under irradiation at exposures in the range of 7 x 10/sup 16/ to 3 x 10/sup 19/ nvt are also included for types 304, types of martensitic and ferritic stainless steels which were evaluated domore » not contain nickel. For application where it is desirable to minimize Co/sup 58/ activity produced from nickel, selection of a martensitic or ferritic stainless steel may be more appropriate than choosing the more popular nickel-bearing austenitic stainless steel or a fuel-element cladding material. Interpretation of the data indicates that, on the average, martensitic and ferritic stainless steels corrode more rapidly than austenitic alloys but more slowly than carbon and low-alloy steels. Under selected controlled water conditions or under irradiation, the corrosion of the nickel-free stainless steels appears to differ little from the austenitics. The corrosion of martensitic and ferritic stainless steels in pressurized-water systems therefore does not appear of such magnitude as to rule out development of these materials as the cladding fuel elements for specific applications. (auth)« less

Marine corrosion of mild steel at Lumut, Perak

NASA Astrophysics Data System (ADS)

Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

2012-09-01

The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

Nuclear Repository steel canister: experimental corrosion rates

NASA Astrophysics Data System (ADS)

Caporuscio, F.; Norskog, K.

2017-12-01

The U.S. Spent Fuel & Waste Science & Technology campaign evaluates various generic geological repositories for the disposal of spent nuclear fuel. This experimental work analyzed and characterized the canister corrosion and steel interface mineralogy of bentonite-based EBS 304 stainless steel (SS), 316 SS, and low-carbon steel coupons in brine at higher heat loads and pressures. Experiments contrasted EBS with and without an argillite wall rock. Unprocessed bentonite from Colony, Wyoming simulated the clay buffer and Opalinus Clay represented the wall rock. Redox conditions were buffered at the magnetite-iron oxygen fugacity univariant curve. A K-Na-Ca-Cl-based brine was chosen to replicate generic granitic groundwater compositions, while Opalinous Clay groundwater was used in the wall rock series of experiments. Most experiments were run at 150 bar and 300°C for 4 to 6 weeks and one was held at elevated conditions for 6 months. The two major experimental mixtures were 1) brine-bentonite clay- steel, and 2) brine-bentonite clay-Opalinus Clay-steel. Both systems were equilibrated at a high liquid/clay ratio. Mineralogy and aqueous geochemistry of each experiment were evaluated to monitor the reactions that took place. In total 4291 measurements were obtained: 2500 measured steel corrosion depths and 1791 were of phyllosilicate mineral reactions/growths at the interface. The low carbon steel corrosion mechanism was via pit corrosion, while 304 SS and 316 SS were by general corrosion. The low carbon steel corrosion rate (1.95 μm/day) was most rapid. The 304 SS corrosion rate (0.37 μm/day) was slightly accelerated versus the 316 SS corrosion rate (0.26 μm/day). Note that the six month 316 SS experiment shows inhibited corrosion rates (0.07 μm/day). This may be in part due to mantling by the Fe-saponite/chlorite authigenic minerals. All phyllosilicate growth rates at the interface exhibit similar growth rate patterns to the steels (i.e. LCS>304>316> 316 six month).

Effect of alpha/gamma phase ratio on corrosion behavior of dual-phase stainless steels.

PubMed

Lim, Y J; Reyes, M; Thongthammachat, S; Sukchit, K; Panich, M; Oshida, Y

1999-01-01

Dual-phase stainless steels have been developed in order to reduce the nickel content, which is potentially responsible to an allergic reaction when these steels are used as medical or dental applications. In this study, two different dual-phase stainless steels (2205 and Z100) were electrochemically tested to evaluate their corrosion resistance in three corrosive solutions (i.e., synthetic saliva, 0.9% NaCl solution, and Ringer solution). Particularly, an attempt was made to correlate the corrosion resistance to a metallographic parameter, which is, in this study, the alpha/gamma phase ratio. It was concluded that (1) type 2205 stainless steel exhibited excellent corrosion resistance in all three corrosion media; however 2205 stainless steel decreases its corrosion resistance by increasing chloride concentration in tested electrolytes from synthetic saliva through 0.9% NaCl solution to Ringer solution. (2) X-ray diffraction analysis indicated that the alpha/gamma phase ratio of 2205 (1.735) was higher than that of Z100 (0.905). As a result, it is suggested that by increasing the alpha/gamma phase ratio the material shows more corrosion-prone behavior when being subjected to a hostile environment containing higher chloride ion concentration.

Microstructure and Corrosive Behavior of Enamel Coating Modified on Mild Steel

NASA Astrophysics Data System (ADS)

Li, Y. L.; Huang, Z. R.; Zhong, Q. D.

Due to the study of marine corrosion of mild steel, in order to simulate the corrosion conditions of enamel coatings in seawater, enamel coatings applied on mild steel were immersed in 3.5wt.% NaCl liquor and the related corrosion features and behavior of enamel were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and evaluated by electro-chemical method such as potentiodynamic polarization testing. Under the appropriate heat treatment system, the enamel coatings sintered on the same kind of mild steel at different temperatures were studied: all enamel samples were within the temperature range from 710∘C to 830∘C, the heat treating process at the microstructural level was evaluated and correlated with corrosion resistance properties. All the enamel coatings were characterized and it was observed that the enamel coatings that showed excellent corrosion resistance when sintered at a temperature of 810∘C can offer a better physical barrier than other temperatures because of their better bonding force and dense microstructure with less pores.

Stress Corrosion Cracking of High Strength Steels

DTIC Science & Technology

1995-06-01

R. Brown, J. H. Graves, E. U. Lee, C. E. Neu and J. Kozol, " Corrosion Behavior of High Strength Steels for Aerospace Applications," Proceedings of...h fit Stress Corrosion Cracking of High Strength Steels Eun U. Lee, Henry Sanders and Bhaskar Sarkar Naval Air Warfare Center Aircraft Division...Patuxent River, Maryland 20670 ABSTRACT The stress corrosion cracking (SCC) was investigated for AerMet 100 and 300M steels in four aqueous NaCl

Microstructure and Corrosion Resistance of Laser Additively Manufactured 316L Stainless Steel

NASA Astrophysics Data System (ADS)

Trelewicz, Jason R.; Halada, Gary P.; Donaldson, Olivia K.; Manogharan, Guha

2016-03-01

Additive manufacturing (AM) of metal alloys to produce complex part designs via powder bed fusion methods such as laser melting promises to be a transformative technology for advanced materials processing. However, effective implementation of AM processes requires a clear understanding of the processing-structure-properties-performance relationships in fabricated components. In this study, we report on the formation of micro and nanoscale structures in 316L stainless steel samples printed by laser AM and their implications for general corrosion resistance. A variety of techniques including x-ray diffraction, optical, scanning and transmission electron microscopy, x-ray fluorescence, and energy dispersive x-ray spectroscopy were employed to characterize the microstructure and chemistry of the laser additively manufactured 316L stainless steel, which are compared with wrought 316L coupons via electrochemical polarization. Apparent segregation of Mo has been found to contribute to a loss of passivity and an increased anodic current density. While porosity will also likely impact the environmental performance (e.g., facilitating crevice corrosion) of AM alloys, this work demonstrates the critical influence of microstructure and heterogeneous solute distributions on the corrosion resistance of laser additively manufactured 316L stainless steel.

Effects of simulated inflammation on the corrosion of 316L stainless steel.

PubMed

Brooks, Emily K; Brooks, Richard P; Ehrensberger, Mark T

2017-02-01

Stainless steel alloys, including 316L, find use in orthopaedics, commonly as fracture fixation devices. Invasive procedures involved in the placement of these devices will provoke a local inflammatory response that produces hydrogen peroxide (H 2 O 2 ) and an acidic environment surrounding the implant. This study assessed the influence of a simulated inflammatory response on the corrosion of 316L stainless steel. Samples were immersed in an electrolyte representing either normal or inflammatory physiological conditions. After 24h of exposure, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to evaluate differences in corrosion behavior and ion release induced by the inflammatory conditions. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to evaluate surface morphology and corrosion products formed on the sample surface. Inflammatory conditions, involving the presence of H 2 O 2 and an acidic pH, significantly alter the corrosion processes of 316L stainless steel, promoting aggressive and localized corrosion. It is demonstrated that particular consideration should be given to 316L stainless steel implants with crevice susceptible areas (ex. screw-head/plate interface), as those areas may have an increased probability of rapid and aggressive corrosion when exposed to inflammatory conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of tempering temperature on pitting corrosion resistance of 420 stainless steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anwar, Moch Syaiful, E-mail: moch026@lipi.go.id; Prifiharni, Siska, E-mail: sisk002@lipi.go.id; Mabruri, Efendi, E-mail: effe004@lipi.go.id

2016-04-19

The AISI Type 420 stainless steels are commonly used to steam generators, mixer blades, etc. These stainless steels are most prone to pitting in dissolved Cl{sup −} containing environments. In this paper, the effect of tempering temperature on pitting corrosion resistance of AISI Type 420 stainless steels was studied. The AISI Type 420 stainless steels specimens were heat treated at the temperature of 1050°C for 1 hour to reach austenite stabilization and then quench in the oil. After that, the specimens were tempered at the temperature of 150, 250, 350 and 450°C for 30 minutes and then air cooled tomore » the room temperature. The electrochemical potentiodynamic polarization test was conducted at 3.5% sodium chloride solution to evaluate corrosion rate and pitting corrosion behaviour. The Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) were used to evaluate the pitting corrosion product. The result have shown that highest pitting potential was found in the sample tempered at 250°C and corrosion pits were found to initiate preferentially around chromium carbides.« less

A Study on Corrosion Inhibitor for Mild Steel in Ethanol Fuel Blend.

PubMed

Vu, Nguyen Si Hoai; Hien, Pham Van; Man, Tran Van; Hanh Thu, Vu Thi; Tri, Mai Dinh; Nam, Nguyen Dang

2017-12-31

The main aim of this study is to investigate Aganonerion polymorphum leaf-ethyl acetate extract (APL-EAE) and its inhibiting effect for steel in ethanol fuel blend. The immersion test, electrochemical and surface analysis techniques were successfully carried out in this research. Scanning electron microscope images indicated that the ethanol fuel blend induced pitting corrosion of steel. Remarkably, the surface of the sample containing 1000 ppm APL-EAE is smoother than the others submerged in different conditions. The electrochemical impedance spectroscopy result shows that APL-EAE has formed a good protective layer, preventing corrosive factors from hitting the steel surface. The potentiodynamic polarization data argue that the corrosion inhibition efficiency was strengthened with the increase of APL-EAE concentration. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated less intensity of Fe peaks, higher intensity of C 1s peak and the appearance of organic peaks (N 1s , P 2p , O 1s ) from specimens with and without APL-EAE addition. Therefore, the results suggest the formation of the protective film on steel surface and affirm that APL-EAE has served as an effective corrosion inhibitor for steel in ethanol fuel blend.

A Study on Corrosion Inhibitor for Mild Steel in Ethanol Fuel Blend

PubMed Central

Vu, Nguyen Si Hoai; Hien, Pham Van; Man, Tran Van; Hanh Thu, Vu Thi; Tri, Mai Dinh

2017-01-01

The main aim of this study is to investigate Aganonerion polymorphum leaf-ethyl acetate extract (APL-EAE) and its inhibiting effect for steel in ethanol fuel blend. The immersion test, electrochemical and surface analysis techniques were successfully carried out in this research. Scanning electron microscope images indicated that the ethanol fuel blend induced pitting corrosion of steel. Remarkably, the surface of the sample containing 1000 ppm APL-EAE is smoother than the others submerged in different conditions. The electrochemical impedance spectroscopy result shows that APL-EAE has formed a good protective layer, preventing corrosive factors from hitting the steel surface. The potentiodynamic polarization data argue that the corrosion inhibition efficiency was strengthened with the increase of APL-EAE concentration. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated less intensity of Fe peaks, higher intensity of C1s peak and the appearance of organic peaks (N1s, P2p, O1s) from specimens with and without APL-EAE addition. Therefore, the results suggest the formation of the protective film on steel surface and affirm that APL-EAE has served as an effective corrosion inhibitor for steel in ethanol fuel blend. PMID:29301224

Electrochemical Corrosion of Stainless Steel in Thiosulfate Solutions Relevant to Gold Leaching

NASA Astrophysics Data System (ADS)

Choudhary, Lokesh; Wang, Wei; Alfantazi, Akram

2016-01-01

This study aims to characterize the electrochemical corrosion behavior of stainless steel in the ammoniacal thiosulfate gold leaching solutions. Electrochemical corrosion response was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy, while the semi-conductive properties and the chemical composition of the surface film were characterized using Mott-Schottky analysis and X-ray photoelectron spectroscopy, respectively. The morphology of the corroded specimens was analyzed using scanning electron microscopy. The stainless steel 316L showed no signs of pitting in the ammoniacal thiosulfate solutions.

Performance of ferritic stainless steels for automobile muffler corrosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarutani, Y.; Hashizume, T.

1995-11-01

Corrosion behavior of ferritic stainless steels was studied in artificial exhaust gas condensates containing corrosive ions such as Cl{sup {minus}} and SO{sub 3}{sup 2{minus}}. Continuous immersion tests in flasks and Dip and Dry tests by using the alternate corrosion tester with a heating system clarified the effects of chromium and molybdenum additions on the corrosion resistance of a ferritic stainless steel in the artificial exhaust gas condensates. Effects of surface oxidation on the corrosion behavior were investigated in a temperature range of 573K to 673K. Oxidation of 673K reduced the corrosion resistance of the ferritic stainless steels in the artificialmore » environment of the automobile muffler. Particulate matter deposited on the muffler inner shell from the automobile exhaust gas was also examined. Deposited particulate matter increased the corrosion rate of the ferritic stainless steel. Finally, the authors also investigated the corrosion of the automobile mufflers made of Type 436L ferritic stainless steel with 18% chromium-1.2% molybdenum after 24 months, in Japan. The sets of results clarified that Type 436L ferritic stainless steel as the material for the automobile muffler exhibited acceptable corrosion resistance.« less

Evaluation of corrosion products formed by sulfidation as inhibitors of the naphthenic corrosion of AISI-316 steel

NASA Astrophysics Data System (ADS)

Sanabria-Cala, J. A.; Montañez, N. D.; Laverde Cataño, D.; Y Peña Ballesteros, D.; Mejía, C. A.

2017-12-01

Naphthenic acids present in oil from most regions worldwide currently stand as the main responsible for the naphthenic corrosion problems, affecting the oil-refining industry. The phenomenon of sulfidation, accompanying corrosion processes brought about by naphthenic acids in high-temperature refining plant applications, takes place when the combination of sulfidic acid (H2S) with Fe forms layers of iron sulphide (FeS) on the material surface, layers with the potential to protect the material from attack by other corrosive species like naphthenic acids. This work assessed corrosion products formed by sulfidation as inhibitors of naphthenic corrosion rate in AISI-316 steel exposed to processing conditions of simulated crude oil in a dynamic autoclave. Calculation of the sulfidation and naphthenic corrosion rates were determined by gravimetry. The surfaces of the AISI-316 gravimetric coupons exposed to acid systems; were characterized morphologically by X-Ray Diffraction (XRD) and X-ray Fluorescence by Energy Dispersive Spectroscopy (EDS) combined with Scanning Electron Microscopy (SEM). One of the results obtained was the determination of an inhibiting effect of corrosion products at 250 and 300°C, where lower corrosion rate levels were detected. For the temperature of 350°C, naphthenic corrosion rates increased due to deposition of naphthenic acids on the areas where corrosion products formed by sulfidation have lower homogeneity and stability on the surface, thus accelerating the destruction of AISI-316 steel. The above provides an initial contribution to oil industry in search of new alternatives to corrosion control by the attack of naphthenic acids, from the formation of FeS layers on exposed materials in the processing of heavy crude oils with high sulphur content.

Super-Hydrophobic Green Corrosion Inhibitor On Carbon Steel

NASA Astrophysics Data System (ADS)

Hassan, H.; Ismail, A.; Ahmad, S.; Soon, C. F.

2017-06-01

There are many examples of organic coatings used for corrosion protection. In particular, hydrophobic and super-hydrophobic coatings are shown to give good protection because of their enhanced ability to slow down transport of water and ions through the coating. The purpose of this research is to develop water repellent coating to avoid direct contact between metal and environment corrosive and mitigate corrosion attack at pipeline system. This water repellent characteristic on super-hydrophobic coating was coated by electrodeposition method. Wettability of carbon steel with super-hydrophobic coating (cerium chloride and myristic acid) and oxidized surface was investigated through contact angle and inhibitor performance test. The inhibitor performance was studied in 25% tannin acid corrosion test at 30°C and 3.5% sodium chloride (NaCl). The water contact angle test was determined by placing a 4-μL water droplet of distilled water. It shows that the wettability of contact angle super-hydrophobic with an angle of 151.60° at zero minute can be classified as super-hydrophobic characteristic. By added tannin acid as inhibitor the corrosion protection on carbon steel becomes more consistent. This reveals that the ability of the coating to withstand with the corrosion attack in the seawater at different period of immersions. The results elucidate that the weight loss increased as the time of exposure increased. However, the corrosion rates for uncoated carbon steel is high compared to coated carbon steel. As a conclusion, from both samples it can be seen that the coated carbon steel has less corrosion rated compared to uncoated carbon steel and addition of inhibitor to the seawater provides more protection to resist corrosion attack on carbon steel.

Effects of gaseous nitriding AISI4140 alloy steel on corrosion and hardness properties

NASA Astrophysics Data System (ADS)

Tamil Moli, L.; Wahab, N.; Gopinathan, M.; Karmegam, K.; Maniyarasi, M.

2016-10-01

Corrosion is one of the major problems in the industry especially on machinery since it weakens the structure of the machinery part and causes the mechanical failure. This will stop the production and increase the maintenance cost. In this study, the corrosion behaviour of gas nitriding on a screw press machine shaft made from AISI 4140 steel was investigated. Pitting corrosion was identified as a major cause of the shaft failure and this study was conducted to improve the corrosion resistance on the AISI 4140 alloy steel shaft by gas nitriding as a surface hardening treatment. Gas nitriding was performed with composition of 15% ammonia and 85% nitrogen at temperatures of 525 °C, 550 °C and 575 °C and with the soaking time of 30, 45 and 60 minutes, respectively. The samples were prepared as rectangular sized of 30mm x 12mm x 3mm for immersion testing. The results showed that corrosion rate of untreated samples was 77% higher compared to the nitrided samples. It was also found that hardness of the nitrided samples was higher than untreated sample. All in all, it can be concluded that gaseous nitriding can significantly improve the surface hardness and the corrosion resistance of the shaft made of AISI 4140 alloy steel, hence reduces the pitting that is the root cause of failure.

Stress Corrosion-Cracking and Corrosion Fatigue Impact of IZ-C17+ Zinc Nickel on 4340 Steel

DTIC Science & Technology

2017-05-17

REPORT NO: NAWCADPAX/TIM-2016/189 STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by...CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by Craig Matzdorf Charles Lei Matt Stanley...5a. CONTRACT NUMBER STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL 5b. GRANT NUMBER 5c. PROGRAM

Effective grain size and charpy impact properties of high-toughness X70 pipeline steels

NASA Astrophysics Data System (ADS)

Hwang, Byoungchul; Kim, Yang Gon; Lee, Sunghak; Kim, Young Min; Kim, Nack J.; Yoo, Jang Yong

2005-08-01

The correlation of microstructure and Charpy V-notch (CVN) impact properties of a high-toughness API X70 pipeline steel was investigated in this study. Six kinds of steel were fabricated by varying the hot-rolling conditions, and their microstructures, effective grain sizes, and CVN impact properties were analyzed. The CVN impact test results indicated that the steels rolled in the single-phase region had higher upper-shelf energies (USEs) and lower energy-transition temperatures (ETTs) than the steels rolled in the two-phase region because their microstructures were composed of acicular ferrite (AF) and fine polygonal ferrite (PF). The decreased ETT in the steels rolled in the single-phase region could be explained by the decrease in the overall effective grain size due to the presence of AF having a smaller effective grain size. On the other hand, the absorbed energy of the steels rolled in the two-phase region was considerably lower because a large amount of dislocations were generated inside PFs during rolling. It was further decreased when coarse martensite or cementite was formed during the cooling process.

Effect of CO2 partial pressure and different CO2 phases on carbon steel corrosion

NASA Astrophysics Data System (ADS)

Mahlobo, MGR; Premlall, K.; Olubambi, PA

2017-12-01

Carbon capture and storage (CCS) is the recent promising technology aimed at reducing greenhouse gas emission. Like many other developed technologies, CCS is faced with great challenges such as pipeline transportation failure due to corrosion. There are many factors contributing to steel corrosion during the pipeline transportation of carbon dioxide (CO2). This study focuses on CO2 partial pressure and different phases of CO2 as some of the factors contributing to steel corrosion. Carbon steel was used as a testing specimen. High pressure reactor was used in this study to compress CO2 from low to high pressures ultimately changing the CO2 from gaseous phase to gas/liquid phase (subcritical) and to dense phase (supercritical). Weight loss method was employed to determine the corrosion rate while scanning electron microscopy (SEM) and X-Ray diffraction (XRD) were used to study the carbon steel morphology and phase analysis. Using low magnification digital camera, the type of corrosion that took place on the carbon steel surface was identified.

High Corrosion Resistance Offered by Multi-Walled Carbon Nanotubes Directly Grown Over Mild Steel Substrate

NASA Astrophysics Data System (ADS)

Arora, Sweety; Rekha, M. Y.; Gupta, Abhay; Srivastava, Chandan

2018-02-01

The inert and hydrophobic nature of carbon nanotubes (CNTs) makes them a potential material for corrosion protection coatings. In this work, a uniform coating of multi-walled CNTs (MWCNTs) was formed over a mild steel substrate by direct decomposition of a ferrocene-benzene mixture over the substrate which was kept inside a chemical vapor deposition setup at a temperature of 800°C. The MWCNTs formed over the substrate were characterized using x-ray diffraction, Raman spectroscopy and transmission electron microscopy techniques. Corrosion behavior of the bare and MWCNT-coated mild steel substrate was examined through potentiodynamic polarization and electrochemical impedance spectroscopy methods. A significant improvement in the corrosion resistance in terms of the reduction in corrosion current and corrosion rate and increase in polarization resistance was noted in the case of the MWCNT-coated mild steel plate. Corrosion resistance increased due to MWCNT coating.

Ultrasonic guided wave for monitoring corrosion of steel bar

NASA Astrophysics Data System (ADS)

Liu, Xi; Qin, Lei; Huang, Bosheng

2018-01-01

Steel corrosion of reinforced concrete structures has become a serious problem all over the word. In this paper, the work aims at monitoring steel corrosion using ultrasonic guided wave (UGW). Ultrasonic guided wave monitoring is a dynamic and non-destructive testing technology. The advantages of ultrasonic guided wave monitoring for reinforcement corrosion are real-time, online and continuous. In addition, it can judge the different stages of steel bar corrosion, which achieved non-destructive detection.

Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

PubMed

Spark, Amy J; Law, David W; Ward, Liam P; Cole, Ivan S; Best, Adam S

2017-08-01

Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

Effects of H2S/HS- on Stress Corrosion Cracking Behavior of X100 Pipeline Steel Under Simulated Sulfate-Reducing Bacteria Metabolite Conditions

NASA Astrophysics Data System (ADS)

Liu, Q.; Li, Z.; Liu, Z. Y.; Li, X. G.; Wang, S. Q.

2017-04-01

The effect of H2S/HS-, which simulates the main metabolites of sulfate-reducing bacteria (SRB), on the electrochemical and stress corrosion cracking (SCC) behaviors of X100 steel was investigated in a near-neutral solution. The results showed that different H2S/HS- contents mainly affected the cathodic process of X100 electrochemical corrosion. As the concentration of H2S/HS- increased, the corrosion potential was shifted negatively, the corrosion current density was considerably increased, and the corrosion rate was linearly increased. Different rust layers with shifting structures were formed under different conditions and had different effects on electrochemical behaviors. However, sulfide mainly promoted local corrosion processes. With the synergistic effects of stress and H2S/HS-, SCC susceptibility was considerably enhanced. The accelerated process of hydrogen evolution by sulfide was crucial in enhancing SCC processes. In brief, the trace H2S/HS- generated by SRB metabolites played a positive role in promoting SCC.

A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel

PubMed Central

Chen, Dong; Yen, Max; Lin, Paul; Groff, Steve; Lampo, Richard; McInerney, Michael; Ryan, Jeffrey

2014-01-01

An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor’s normalized electrical resistance (R/R0) decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor’s normalized capacitance (C/C0) increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite. PMID:28788158

Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere

NASA Astrophysics Data System (ADS)

Li, Dong-liang; Fu, Gui-qin; Zhu, Miao-yong; Li, Qing; Yin, Cheng-xiang

2018-03-01

The corrosion resistance of weathering bridge steels containing conventional contents of Ni (0.20wt%, 0.42wt%, 1.50wt%) and a higher content of Ni (3.55wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low (≤0.42wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher ( 3.55wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe2O2 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42wt% to 1.50wt%, the corrosion resistance of the bridge steel increased only slightly.

Resistance of Some Steels to Stress Corrosion Cracking

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Nelson, E. E.

1982-01-01

Evaluations of stress-corrosion cracking resistance of five high-strength low-alloy steels described in report now available. Steels were heat-treated to various tensile strengths and found to be highly resistant to stress-corrosion cracking.

All-Optical Photoacoustic Sensors for Steel Rebar Corrosion Monitoring.

PubMed

Du, Cong; Owusu Twumasi, Jones; Tang, Qixiang; Guo, Xu; Zhou, Jingcheng; Yu, Tzuyang; Wang, Xingwei

2018-04-27

This article presents an application of an active all-optical photoacoustic sensing system with four elements for steel rebar corrosion monitoring. The sensor utilized a photoacoustic mechanism of gold nanocomposites to generate 8 MHz broadband ultrasound pulses in 0.4 mm compact space. A nanosecond 532 nm pulsed laser and 400 μm multimode fiber were employed to incite an ultrasound reaction. The fiber Bragg gratings were used as distributed ultrasound detectors. Accelerated corrosion testing was applied to four sections of a single steel rebar with four different corrosion degrees. Our results demonstrated that the mass loss of steel rebar displayed an exponential growth with ultrasound frequency shifts. The sensitivity of the sensing system was such that 0.175 MHz central frequency reduction corresponded to 0.02 g mass loss of steel rebar corrosion. It was proved that the all-optical photoacoustic sensing system can actively evaluate the corrosion of steel rebar via ultrasound spectrum. This multipoint all-optical photoacoustic method is promising for embedment into a concrete structure for distributed corrosion monitoring.

All-Optical Photoacoustic Sensors for Steel Rebar Corrosion Monitoring

PubMed Central

Du, Cong; Owusu Twumasi, Jones; Tang, Qixiang; Guo, Xu; Zhou, Jingcheng; Yu, Tzuyang; Wang, Xingwei

2018-01-01

This article presents an application of an active all-optical photoacoustic sensing system with four elements for steel rebar corrosion monitoring. The sensor utilized a photoacoustic mechanism of gold nanocomposites to generate 8 MHz broadband ultrasound pulses in 0.4 mm compact space. A nanosecond 532 nm pulsed laser and 400 μm multimode fiber were employed to incite an ultrasound reaction. The fiber Bragg gratings were used as distributed ultrasound detectors. Accelerated corrosion testing was applied to four sections of a single steel rebar with four different corrosion degrees. Our results demonstrated that the mass loss of steel rebar displayed an exponential growth with ultrasound frequency shifts. The sensitivity of the sensing system was such that 0.175 MHz central frequency reduction corresponded to 0.02 g mass loss of steel rebar corrosion. It was proved that the all-optical photoacoustic sensing system can actively evaluate the corrosion of steel rebar via ultrasound spectrum. This multipoint all-optical photoacoustic method is promising for embedment into a concrete structure for distributed corrosion monitoring. PMID:29702554

Quantitative Study on Corrosion of Steel Strands Based on Self-Magnetic Flux Leakage.

PubMed

Xia, Runchuan; Zhou, Jianting; Zhang, Hong; Liao, Leng; Zhao, Ruiqiang; Zhang, Zeyu

2018-05-02

This paper proposed a new computing method to quantitatively and non-destructively determine the corrosion of steel strands by analyzing the self-magnetic flux leakage (SMFL) signals from them. The magnetic dipole model and three growth models (Logistic model, Exponential model, and Linear model) were proposed to theoretically analyze the characteristic value of SMFL. Then, the experimental study on the corrosion detection by the magnetic sensor was carried out. The setup of the magnetic scanning device and signal collection method were also introduced. The results show that the Logistic Growth model is verified as the optimal model for calculating the magnetic field with good fitting effects. Combined with the experimental data analysis, the amplitudes of the calculated values ( B xL ( x,z ) curves) agree with the measured values in general. This method provides significant application prospects for the evaluation of the corrosion and the residual bearing capacity of steel strand.

Corrosion Behavior and Durability of Low-Alloy Steel Rebars in Marine Environment

NASA Astrophysics Data System (ADS)

Liu, Ming; Cheng, Xuequn; Li, Xiaogang; Yue, Pan; Li, Jun

2016-11-01

The corrosion resistance of Cr-modified low-alloy steels and HRB400 carbon steel was estimated using the open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopic, and weight loss methods in simulated concrete pore solution. Results show that Cr-modified steels exhibit a higher corrosion resistance with a higher critical chloride level (CTL), lower corrosion current density, and higher impedance than carbon steel. The CTL of the steels significantly reduces with increasing temperature. Weight loss measurement shows that the Cr-modified steels exhibit low corrosion rates and small corrosion pitting. The primary constituents of the corrosion scales are Fe2O3, Fe3O4, β-FeOOH, γ-FeOOH, and α-FeOOH. A large amount of α-FeOOH could be detected in the Cr-modified steel corrosion products. Moreover, the Cr-modified steels demonstrate a higher durability than HRB400 carbon steel.

The structural and bio-corrosion barrier performance of Mg-substituted fluorapatite coating on 316L stainless steel human body implant

NASA Astrophysics Data System (ADS)

Sharifnabi, A.; Fathi, M. H.; Eftekhari Yekta, B.; Hossainalipour, M.

2014-01-01

In this study, Mg-substituted fluorapatite coatings were deposited on medical grade AISI 316L stainless steel via sol-gel dip coating method. Phase composition, crystallite size and degree of crystallinity of the obtained coatings were evaluated by X-ray diffraction (XRD) analysis. Fourier transform infrared (FTIR) spectroscopy was also used to evaluate functional groups of the obtained coatings. The surface morphology and cross-section of the final coatings were studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy was used to determine elemental chemical composition of the obtained coatings. In order to determine and compare the corrosion behavior of uncoated and Mg-substituted fluorapatite coated 316L stainless steel, electrochemical potentiodynamic polarization tests were performed in physiological solutions at 37 ± 1 °C. Moreover, the released metallic ions from uncoated and coated substrates were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) within 2 months of immersing in Ringer's solution at 36.5 ± 1 °C as an indication of biocompatibility. The results showed that fluoride and magnesium were successfully incorporated into apatite lattice structure and the prepared coatings were nanostructured with crystallinity of about 70%. Obtained coatings were totally crack-free and uniform and led to decrease in corrosion current densities of 316L stainless steel in physiological solutions. In addition, coated sample released much less ions such as Fe, Cr and Ni in physiological media. Therefore, it was concluded that Mg-substituted fluorapatite coatings could improve the corrosion resistance and biocompatibility of 316L stainless steel human body implants.

Simulation on the steel galvanic corrosion and acoustic emission

NASA Astrophysics Data System (ADS)

Yu, Yang; Shi, Xin; Yang, Ping

2015-12-01

Galvanic corrosion is a very destructive localized corrosion. The research on galvanic corrosion could determine equipment corrosion and prevent the accidents occurrence. Steel corrosion had been studied by COMSOL software with mathematical modeling. The galvanic corrosion of steel-aluminum submerged into 10% sodium chloride solution had been on-line detected by PIC-2 acoustic emission system. The results show that the acoustic emission event counts detected within unit time can qualitative judge galvanic corrosion rate and further erosion trend can be judged by the value changes.

Effect of Acidified Feronia elephantum Leaf Extract on the Corrosion Behavior of Mild Steel

NASA Astrophysics Data System (ADS)

Muthukrishnan, Pitchaipillai; Prakash, Periakaruppan; Ilayaraja, Murugan; Jeyaprabha, Balasubramanian; Shankar, Karikalan

2015-03-01

Mild steel is used as a structural material for pipes, tank, reaction vessels, etc. which are known to corrode invariably in contact with various solvents. From the view point of a nation's economy and financial implications of corrosion hazard, it is necessary to adopt appropriate means and ways to reduce the losses due to corrosion. The use of eco-friendly corrosion inhibitors are increasing day by day. Feronia elephantum leaf extract (FELE) has been tested as eco-friendly corrosion inhibitor for A262 mild steel in 1 M H2SO4 and 1 M HCl solutions using non-electrochemical (Gravimetric, X-ray diffraction analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy) and electrochemical techniques (open circuit potential, potentiostatic polarization, and electrochemical impedance measurements). The protection efficiency is found to increase with increase in FELE concentration but decrease with temperature, which is suggestive of physical adsorption mechanism. The adsorption of FELE on mild steel surface obeys the Langmuir adsorption isotherm. SEM results confirm the formation of a protective layer by FELE over mild steel surface.

Effect of tungsten on the corrosion behavior of sulfuric acid-resistant steels for flue gas desulfurization system

NASA Astrophysics Data System (ADS)

Ji, Woo-Soo; Jang, Young-Wook; Kim, Jung-Gu

2011-06-01

Flue gas desulfurization systems (FGDs) are operated in severely corrosive environments that cause sulfuric acid dew-point corrosion. The corrosion behavior of low-alloy steels was tested using electrochemical techniques (electrochemical impedance spectroscopy, potentiodynamic tests, potentiostatic tests), and the corrosion products were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical results showed that alloying W with small amounts of Sb, Cu, and Co improves the corrosion resistance of steels. The results of surface analyses showed that the surface of the steels alloyed with W consisted of W oxides and higher amounts of Sb and Cu oxides. This suggests that the addition of W promotes the formation of a protective WO3 film, in addition to Sb2O5 and CuO films on the surface.

Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

NASA Astrophysics Data System (ADS)

Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

2015-07-01

The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

Effects of Sn and Sb on the corrosion resistance of AH 32 steel in a cargo oil tank environment

NASA Astrophysics Data System (ADS)

Ahn, SooHoon; Park, Kyung Jin; Oh, KkochNim; Hwang, SungDoo; Park, ByungJoon; Kwon, HyukSang; Shon, MinYoung

2015-09-01

Effects of the alloying elements, Sn and Sb, on the corrosion resistance of modified AH 32 steel for the cargo oil tanks (COT) were examined using an electrochemical test and weight loss measurement. All experiments were carried out in acidic chloride solution (0.14 M HCl and 10 wt% NaCl, pH 0.85) at 30 °C, simulating the inner bottom plate of COT. It was clearly found that the small amount addition of Sn and Sb improved the corrosion resistance of modified AH 32 steel, which is confirmed by the higher polarization resistance of AH 32 steel modified with Sn and Sb addition compared with that of the base steel. X-ray photoelectron spectroscopy analysis of the corroded surface after immersion of 72 h presented that the AH 32 steel modified with Sn and Sb addition created the protective corrosion products including SnO2 and Sb2O5. These oxides act as high corrosion inhibitor to anodic corrosion reaction, and hence leading to the improvement in the corrosion resistance of the modified AH 32 steels.

Effect of Mo contents on corrosion behaviors of welded duplex stainless steel

NASA Astrophysics Data System (ADS)

Bae, Seong Han; Lee, Hae Woo

2013-05-01

The corrosion behaviour and change of the phase fraction in welded 24Cr Duplex stainless steel was investigated for different chemical composition ranges of Mo contents. Filler metal was produced by fixing the contents of Cr, Ni, N, and Mn while adjusting the Mo content to 0.5, 1.4, 2.5, 3.5 wt%. The δ-ferrite fraction was observed to increase as the content of Mo increased. A polarisation test conducted in a salt solution, indicated the pitting corrosion potential increased continuously to 3.5 wt% Mo, while the corrosion potential changed most between 0.5 and 1.41 wt% Mo. The location of the pitting corrosion in 0.5 wt% Mo steel was randomly distributed, but it occurred selectively at the grain boundary between the γ- and δ-ferrite phases in 1.4, 2.5 and 3.5 wt% Mo steel. Energy dispersive X-ray spectroscopy mapping analysis showed that areas deficient in Cr, Mo, and Ni occurred around the grain boundary of the γ- and δ-ferrite phases. Non-metallic inclusions are thought to act as initiation points for the pitting corrosion that occurs in the salt solution initially as a result of the potential difference between the matrix structure and the incoherent inclusions.

Prediction of stress corrosion of carbon steel by nuclear process liquid wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ondrejcin, R.S.

1978-08-01

Radioactive liquid wastes are produced as a consequence of processing fuel from Savannah River Plant (SRP) production reactors. These wastes are stored in mild steel waste tanks, some of which have developed cracks from stress corrosion. A laboratory test was developed to determine the relative agressiveness of the wastes for stress corrosion cracking of mild steel. Tensile samples were strained to fracture in synthetic waste solutions in an electrochemical cell with the sample as the anode. Crack initiation is expected if total elongation of the steel in the test is less than its uniform elongation in air. Cracking would bemore » anticipated in a plant waste tank if solution conditions were equivalent to test conditions that cause a total elongation that is less than uniform elongation. The electrochemical tensile tests showed that the supernates in salt receiver tanks at SRP have the least aggressive compositions, and wastes newly generated during fuel repocessing have the most aggressive ones. Test data also verified that ASTM A 516-70 steel used in the fabrication of the later design waste tanks is less susceptible to cracking than the ASTM A 285-B steel used in earlier designs.« less

Bacillus sp. Acting as Dual Role for Corrosion Induction and Corrosion Inhibition with Carbon Steel (CS)

PubMed Central

Karn, Santosh K.; Fang, Guan; Duan, Jizhou

2017-01-01

Present work investigated the role of five different bacteria species as a corrosion inducer as well as corrosion inhibitor with carbon steel (CS). We observed the ability of different bacteria species on the metal surface attachment, biofilm formation, and determined Peroxidase, Catalase enzyme activity in the detached biofilm from the CS surface. We found that each strain has diverse conduct for surface attachment like DS1 3.3, DS2 2.5, DS3 4.3, DS4 4.0, and DS5 4.71 log cfu/cm2 and for biofilm 8.3 log cfu/cm2. The enzyme Peroxidase, Catalase was found in huge concentration inside the biofilm Peroxidase was maximum for DS4 36.0 U/ml and least for DS3 19.54 U/ml. Whereas, Catalase was highest for DS4, DS5 70.14 U/ml and least 57.2 U/ml for DS2. Scanning electron microscopy (SEM) was conducted to examine the biofilm and electrochemical impedance spectroscopy (EIS) were utilized to observe corrosion in the presence of bacteria. The electrochemical results confirmed that DS1, DS3, DS4, and DS5 strains have statistically significant MIC-factors (Microbially Influenced Corrosion) of 5.46, 8.51, 2.36, and 1.04, while DS2 protective effect factor of 0.89. Weight reduction results with carbon steel likewise supports that corrosion was initiated by DS1 and DS3, while DS2 and DS5 have no any impact though with DS4 we watched less weight reduction however assumed no role in the corrosion. We established the relation of Peroxidase enzyme activity of the isolates. DS1, DS3 and having Peroxidase in the range 22.18, 19.54 U/ml which induce the corrosion whereas DS2 and DS5 having 28.57 and 27.0 U/ml has no any effect and DS4 36 U/ml has inhibitory effect, increasing concentration inhibiting the corrosion. For Catalase DS1, DS3 have 67.28, 61.57 U/ml which induce corrosion while DS2 and DS5 57.71 and 59.14 U/ml also has no effect whereas DS4 70.14 U/ml can inhibit corrosion. Results clearly express that in a specific range both enzymes can induce the corrosion. Our goals are to

Corrosion resistance of premodeled wires made of stainless steel used for heart electrotherapy leaders

NASA Astrophysics Data System (ADS)

Przondziono, J.; Walke, W.; Młynarski, R.; Szatka, W.

2012-05-01

The purpose of the study is to evaluate resistance to electrochemical corrosion of wire made of X10CrNi18-8 stainless steel designed for use in cardiology treatment. The influence of strain formed in the premodeling process and methods of wire surface preparation to corrosive resistance in artificial plasma solution were analysed. Wire corrosion tests were carried out in the solution of artificial plasma. Resistance to electrochemical corrosion was evaluated on the ground of recorded curves of anodic polarization by means of potentiodynamic method. Potentiodynamic tests carried out enabled to determine how the resistance to pitting corrosion of wire changes, depending on strain formed in the premodeling process as well as on the method of wire surface preparation. For evaluation of phenomena occurring on the surface of tested steel, electrochemical impedance spectroscopy (EIS) was applied. Deterioration of corrosive properties of wire along with the increase in the formed strain hardening was observed.

Liquid Coatings for Reducing Corrosion of Steel in Concrete

NASA Technical Reports Server (NTRS)

MacDowell, Louis G.; Curran, Joseph

2003-01-01

Inorganic coating materials are being developed to slow or stop corrosion of reinforcing steel members inside concrete structures. It is much simpler and easier to use these coating materials than it is to use conventional corrosion-inhibiting systems based on impressed electric currents. Unlike impressed electrical corrosion-inhibiting systems, these coatings do not require continuous consumption of electrical power and maintenance of power-supply equipment. Whereas some conventional systems involve the use of expensive arc-spray equipment to apply the metallic zinc used as the sacrificial anode material, the developmental coatings can be applied by use of ordinary paint sprayers. A coating material of the type under development is formulated as a liquid containing blended metallic particles and/or moisture-attracting compounds. The liquid mixture is sprayed onto a concrete structure. Experiments have shown that even though such a coat resides on the exterior surface, it generates a protective galvanic current that flows to the interior reinforcing steel members. By effectively transferring the corrosion process from the steel reinforcement to the exterior coating, the protective current slows or stops corrosion of the embedded steel. Specific formulations have been found to meet depolarization criteria of the National Association of Corrosion Engineers (NACE) for complete protection of steel reinforcing bars ("rebar") embedded in concrete.

Mechanical Behavior of Stainless Steel Fiber-Reinforced Composites Exposed to Accelerated Corrosion

PubMed Central

O’Brien, Caitlin; McBride, Amanda; E. Zaghi, Arash; Burke, Kelly A.; Hill, Alex

2017-01-01

Recent advancements in metal fibers have introduced a promising new type of stainless steel fiber with high stiffness, high failure strain, and a thickness < 100 μm (<0.00394 in.) that can be utilized in a steel fiber-reinforced polymer. However, stainless steel is known to be susceptible to pitting corrosion. The main goal of this study is to compare the impact of corrosion on the mechanical properties of steel fiber-reinforced composites with those of conventional types of stainless steel. By providing experimental evidences, this study may promote the application of steel fiber-reinforced composite as a viable alternative to conventional metals. Samples of steel fiber-reinforced polymer and four different types of stainless steel were subjected to 144 and 288 h of corrosion in ferric chloride solution to simulate accelerated corrosion conditions. The weight losses due to corrosion were recorded. The corroded and control samples were tested under monotonic tensile loading to measure the ultimate stresses and strains. The effect of corrosion on the mechanical properties of the different materials was evaluated. The digital image correlation (DIC) technique was used to investigate the failure mechanism of the corrosion-damaged specimens. Overall, steel fiber-reinforced composites had the greatest corrosion resistance. PMID:28773132

The effect of various deformation processes on the corrosion behavior of casing and tubing carbon steels in sweet environment

NASA Astrophysics Data System (ADS)

Elramady, Alyaa Gamal

susceptibility to SCC when they were cold-rolled and cold-expanded. The research found that surface compressive stresses have an effect on the SCC behavior of casing and tubing steels. The CO2 corrosion behavior and atomic processes at the corroding interface were investigated at laboratory temperature using electrochemical techniques. Cold-work was found to have an influence on the corrosion behavior of both API 5CT K55 and P110 grade steels. These behaviors were found to be material and process dependent. Surface evaluation techniques such as field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) analysis did not detect formation of a protective scale. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) analysis both detected the appearance of a scale that was traced back to magnetite.

Investigation of corrosion of welded joints of austenitic and duplex stainless steels

NASA Astrophysics Data System (ADS)

Topolska, S.

2016-08-01

Investigation of corrosion resistance of materials is one of the most important tests that allow determining their functional properties. Among these tests the special group consist electrochemical investigations, which let to accelerate the course of the process. These investigations allow rapidly estimating corrosion processes occurring in metal elements under the influence of the analysed environment. In the paper are presented results of investigations of the resistance to pitting corrosion of the steel of next grades: austenitic 316L and duplex 2205. It was also analysed the corrosion resistance of welded joints of these grades of steel. The investigations were conducted in two different corrosion environments: in the neutral one (3.5 % sodium chloride) and in the aggressive one (0.1 M sulphuric acid VI). The obtained results indicate different resistance of analysed grades of steel and their welded joints in relation to the corrosion environment. The austenitic 316L steel characterizes by the higher resistance to the pitting corrosion in the aggressive environment then the duplex 2205 steel. In the paper are presented results of potentiodynamic tests. They showed that all the specimens are less resistant to pitting corrosion in the environment of sulphuric acid (VI) than in the sodium chloride one. The 2205 steel has higher corrosion resistance than the 316L stainless steel in 3.5% NaCl. On the other hand, in 0.1 M H2SO4, the 316L steel has a higher corrosion resistance than the 2205 one. The weld has a similar, very good resistance to pitting corrosion like both steels.

Effects of chloride ions on corrosion of ductile iron and carbon steel in soil environments.

PubMed

Song, Yarong; Jiang, Guangming; Chen, Ying; Zhao, Peng; Tian, Yimei

2017-07-31

Chloride is reported to play a significant role in corrosion reactions, products and kinetics of ferrous metals. To enhance the understanding of the effects of soil environments, especially the saline soils with high levels of chloride, on the corrosion of ductile iron and carbon steel, a 3-month corrosion test was carried out by exposing ferrous metals to soils of six chloride concentrations. The surface morphology, rust compositions and corrosion kinetics were comprehensively studied by visual observation, scanning electron microscopy (SEM), X-Ray diffraction (XRD), weight loss, pit depth measurement, linear polarization and electrochemical impedance spectroscopy (EIS) measurements. It showed that chloride ions influenced the characteristics and compositions of rust layers by diverting and participating in corrosion reactions. α-FeOOH, γ-FeOOH and iron oxides were major corrosion products, while β-Fe 8 O 8 (OH) 8 Cl 1.35 rather than β-FeOOH was formed when high chloride concentrations were provided. Chloride also suppressed the decreasing of corrosion rates, whereas increased the difficulty in the diffusion process by thickening the rust layers and transforming the rust compositions. Carbon steel is more susceptible to chloride attacks than ductile iron. The corrosion kinetics of ductile iron and carbon steel corresponded with the probabilistic and bilinear model respectively.

The Influence of Porosity on Corrosion Attack of Austenitic Stainless Steel

NASA Astrophysics Data System (ADS)

Abdullah, Z.; Ismail, A.; Ahmad, S.

2017-10-01

Porous metals also known as metal foams is a metallic body having spaces orpores through which liquid or air may pass. Porous metals get an attention from researchers nowadays due to their unique combination of properties includes excellent mechanical and electrical, high energy absorption, good thermal and sound insulation and water and gas permeability. Porous metals have been applied in numerous applications such as in automotive, aerospace and also in biomedical applications. This research reveals the influence of corrosion attack in porous austenitic stainless steel 316L. The cyclic polarization potential analysis was performed on the porous austenitic stainless steel 316L in 3.5% NaCl solution. The morphology and the element presence on the samples before and after corrosion attack was examined using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) respectively to determine the corrosion mechanism structure. The cyclic polarization potential analysis showed the result of (E corr ) for porous austenitic stainless steel type 316L in the range of -0.40v to -0.60v and breakdown potential (E b ) is -0.3v to -0.4v in NaCl solution.

A technique for predicting steel corrosion resistance

NASA Astrophysics Data System (ADS)

Novikov, V. F.; Sokolov, R. A.; Neradovskiy, D. F.; Muratov, K. R.

2018-01-01

Research works were carried out to develop a technique with the aim to increase the lifetime of steel items used in corrosive media. The possibility to monitor corrosion parameters of steel samples is analyzed on the basis of magnetic properties obtained by means of a magnetic structuroscope DIUS-1.15M designed by the Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences (IMP UB RAS).

21 CFR 178.3300 - Corrosion inhibitors used for steel or tinplate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Corrosion inhibitors used for steel or tinplate... and Production Aids § 178.3300 Corrosion inhibitors used for steel or tinplate. Corrosion inhibitors may be safely used for steel or tinplate intended for use in, or to be fabricated as, food containers...

Effect of Deformation Parameters on Microstructure and Properties During DIFT of X70HD Pipeline Steel

NASA Astrophysics Data System (ADS)

Wang, Jian; Zhu, Wei; Xiao, Hong; Zhang, Liang-liang; Qin, Hao; Yu, Yue

2018-02-01

Grain refinement is a critical approach to improve the strength of materials without damaging the toughness. The grains of deformation-induced ferrite are considerably smaller than those of proeutectoid ferrite. Grain refinement is crucial to the application of deformation-induced ferrite. The composition of ferrite and bainite or martensite is important in controlling the performance of X70HD pipeline steel, and cooling significantly influences the control of their ratio and grain size. By analyzing the static and dynamic phase-transition points using Gleeble-3800 thermal simulator, thermal simulations were performed through two-stage deformations in the austenite zone. Ferrite transformation rules were studied with thermal simulation tests under different deformation and cooling parameters based on the actual production of cumulative deformation. The influence of deformation parameters on the microstructure transformation was analyzed. Numerous fine-grain deformation-induced ferrites were obtained by regulating various parameters, including deformation temperature, strain rate, cooling rate, final cooling temperature and other parameters. Results of metallographic observation and microtensile testing revealed that the selection of appropriate parameters can refine the grains and improve the performance of the X70HD pipeline steel.

A Micro-Mechanism-Based Continuum Corrosion Fatigue Damage Model for Steels

NASA Astrophysics Data System (ADS)

Sun, Bin; Li, Zhaoxia

2018-05-01

A micro-mechanism-based corrosion fatigue damage model is developed for studying the high-cycle corrosion fatigue of steel from multi-scale viewpoint. The developed physical corrosion fatigue damage model establishes micro-macro relationships between macroscopic continuum damage evolution and collective evolution behavior of microscopic pits and cracks, which can be used to describe the multi-scale corrosion fatigue process of steel. As a case study, the model is used to predict continuum damage evolution and number density of the corrosion pit and short crack of steel component in 5% NaCl water under constant stress amplitude at 20 kHz, and the numerical results are compared with experimental results. It shows that the model is effective and can be used to evaluate the continuum macroscopic corrosion fatigue damage and study microscopic corrosion fatigue mechanisms of steel.

A Micro-Mechanism-Based Continuum Corrosion Fatigue Damage Model for Steels

NASA Astrophysics Data System (ADS)

Sun, Bin; Li, Zhaoxia

2018-04-01

A micro-mechanism-based corrosion fatigue damage model is developed for studying the high-cycle corrosion fatigue of steel from multi-scale viewpoint. The developed physical corrosion fatigue damage model establishes micro-macro relationships between macroscopic continuum damage evolution and collective evolution behavior of microscopic pits and cracks, which can be used to describe the multi-scale corrosion fatigue process of steel. As a case study, the model is used to predict continuum damage evolution and number density of the corrosion pit and short crack of steel component in 5% NaCl water under constant stress amplitude at 20 kHz, and the numerical results are compared with experimental results. It shows that the model is effective and can be used to evaluate the continuum macroscopic corrosion fatigue damage and study microscopic corrosion fatigue mechanisms of steel.

Ultrasonic Corrosion Fatigue Behavior of High Strength Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Ebara, R.; Yamaguchi, Y.; Kanei, D.; Yamamoto, Y.

Ultrasonic corrosion fatigue tests were conducted for high strength austenitic stainless steels such as YUS270 and SUS304N2 in 3%NaCl aqueous solution. The reduction of giga-cycle corrosion fatigue strength of YUS270 and SUS304N2 was not observed at all, while the reduction of corrosion fatigue life was observed at higher stress amplitude. Corrosion pit was observed on corrosion fatigue crack initiation area. Striation was predominantly observed on crack propagation area in air and in 3% NaCl aqueous solution. The reduction of corrosion fatigue strength of high strength austenitic stainless steels such as YUS270 and SUS304N2 is due to the corrosion pit formation at corrosion fatigue crack initiation area. It can be concluded that the higher the ultimate tensile strength of austenitic stainless steels the higher the giga-cycle corrosion fatigue strength in 3%NaCl aqueous solution is.

Evaluating the Passivation of Corrosion of API-X100 Steel with Cyclic Voltammetry

NASA Astrophysics Data System (ADS)

Eliyan, Faysal Fayez; Alfantazi, Akram

2017-10-01

In this research, cyclic voltammetry, in oxygen-free low bicarbonate-carbonate solutions, was used to study the corrosion reactions of a high-strength steel, API-X100. With cycles of different scan ranges, the effects of cycling, transpassivation, and cathodic reduction on the electrochemistry of the passive films were analyzed. It was found that carbonate in higher concentrations reduces the anodic activity and the cathodic reactions of the surface. Bicarbonate in small concentrations in solutions that contained low carbonate concentrations catalyzed dissolution and disrupted the formation of the passive films, in reference to the measured anodic currents. From the experiments, there was electrochemical evidence that with more cycles, the passive films were growing thicker, the transpassivation deteriorated the passive films, and during the cathodic reduction, the dissolution was occurring at lower potentials to facilitate later the passivation at higher potentials.

Corrosion Protection Of Mild Steel In Sea Water Using Chemical Inhibitor

NASA Astrophysics Data System (ADS)

Araoyinbo, Alaba O.; Salleh, Mohd Arif Anuar Mohd; Zulerwan Jusof, Muhammad

2018-03-01

The effect of sodium nitrite as a corrosion inhibitor of mild steel in sea water (i.e ASTM standard prepared sea water and sea water obtained from a local river) was investigated, using the weight loss technique. Different amount of sodium nitrite were prepared (i.e 2 % to 10 %) in the inhibition of the mild steel corrosion in sea water exposed to irradiation condition from sunlight exposure. The cut samples of mild steel were exposed to these corrosive media and the corresponding weight loss subsequently obtained was recorded at intervals of 1 to 4 weeks. It was observed that corrosion rate increases with the time of exposure to the corrosive medium exposed to sunlight and that sodium nitrite that was used at the chemical inhibitor was able to retard the corrosion rate of mild steel if the appropriate concentration is applied. The results obtained from the weight loss analysis shows that the optimum percentage of sodium nitrate in sea water that gives the optimum corrosion inhibition of mild steel is 4 %.

Research on corrosion mechanism of suspension insulator steel foot of direct current system and measures for corrosion inhibition

NASA Astrophysics Data System (ADS)

Chen, He; Yang, Yueguang; Su, Guolei; Wang, Xiaoqing; Zhang, Hourong; Sun, Xiaoyu; Fan, Youping

2017-09-01

There are increasingly serious electrocorrosion phenomena on insulator hardware caused by direct current transmission due to the wide-range popularization of extra high voltage direct current transmission engineering in our country. Steel foot corrosion is the main corrosion for insulators on positive polarity side of transmission lines. On one hand, the corrosion leads to the tapering off of steel foot diameter, having a direct influence on mechanical property of insulators; on the other hand, in condition of corrosion on steel foot wrapped in porcelain ware, the volume of the corrosion product is at least 50% more than that of the original steel foot, leading to bursting of porcelain ware, threatening safe operation of transmission lines. Therefore, it is necessary to conduct research on the phenomenon and propose feasible measures for corrosion inhibition. Starting with the corrosion mechanism, this article proposes two measures for corrosion inhibition, and verifies the inhibition effect in laboratory conditions, providing reference for application in engineering.

Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete.

PubMed

Simescu, Florica; Idrissi, Hassane

2008-12-01

We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 . After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

NASA Astrophysics Data System (ADS)

Simescu, Florica; Idrissi, Hassane

2008-12-01

We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

PubMed Central

Simescu, Florica; Idrissi, Hassane

2008-01-01

We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating. PMID:27878037

Progress in the Research of Fatigue of Weathering Steel after Corrosion

NASA Astrophysics Data System (ADS)

Jianyu, Liang; Jian, Yao; Youwu, Xu

2017-12-01

Weathering steel has a good corrosion resistance in the atmosphere, and the application of weathering steel in civil structure also reduces the cost of painting and maintenance. It is also possible for the bare weathering steel to bear the fatigue load with a rust layer. This paper summarizes the fatigue researches after corrosion of weathering steel, including the shape of specimens, failure modes of fatigue and the conclusions obtained through experimental investigations. It is also introduced the fatigue model of weathering steel after corrosion, which can be useful for the engineering application or further researches.

Steel Bar corrosion monitoring based on encapsulated piezoelectric sensors

NASA Astrophysics Data System (ADS)

Xu, Ying; Tang, Tianyou

2018-05-01

The durability of reinforced concrete has a great impact on the structural bearing capacity, while the corrosion of steel bars is the main reason for the degradation of structural durability. In this paper, a new type of encapsulated cement based piezoelectric sensor is developed and its working performance is verified. The consistency of the finite element simulation and the experimental results shows the feasibility of monitoring the corrosion of steel bars using encapsulated piezoelectric sensors. The research results show that the corrosion conditions of the steel bars can be determined by the relative amplitude of the measured signal through the encapsulated piezoelectric sensor.

Accelerated corrosion of stainless steel in thiocyanate-containing solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pistorius, P Chris; Li, Wen

2012-09-19

It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, whichmore » is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk

Evaluation of corrosion resistance of microalloyed reinforcing steel

DOT National Transportation Integrated Search

2004-02-01

The corrosion resistance of three microalloyed steels and two conventional reinforcing steels in concrete was evaluated. The microalloyed steels contain concentrations of chromium, copper, and phosphorus that, while low, are significantly higher than...

High temperature chlorosilane corrosion of iron and AISI 316L stainless steel

NASA Astrophysics Data System (ADS)

Aller, Joshua Loren

Chlorosilane gas streams are used at high temperatures (>500°C) throughout the semiconductor, polycrystalline silicon, and fumed silica industries, primarily as a way to refine, deposit, and produce silicon and silicon containing materials. The presence of both chlorine and silicon in chlorosilane species creates unique corrosion environments due to the ability of many metals to form both metal-chlorides and metal-silicides, and it is further complicated by the fact that many metal-chlorides are volatile at high-temperatures while metal-silicides are generally stable. To withstand the uniquely corrosive environments, expensive alloys are often utilized, which increases the cost of final products. This work focuses on the corrosion behavior of iron, the primary component of low-cost alloys, and AISI 316L, a common low-cost stainless steel, in environments representative of industrial processes. The experiments were conducted using a customized high temperature chlorosilane corrosion system that exposed samples to an atmospheric pressure, high temperature, chlorosilane environment with variable input amounts of hydrogen, silicon tetrachloride, and hydrogen chloride plus the option of embedding samples in silicon during the exposure. Pre and post exposure sample analysis including scanning electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, and gravimetric analysis showed the surface corrosion products varied depending on the time, temperature, and environment that the samples were exposed to. Most commonly, a volatile chloride product formed first, followed by a stratified metal silicide layer. The chlorine and silicon activities in the corrosion environment were changed independently and were found to significantly alter the corrosion behavior; a phenomenon supported by computational thermodynamic equilibrium simulations. It was found that in comparable environments, the stainless steel corroded significantly less than the pure iron. This

Correlation of rolling condition, microstructure, and low-temperature toughness of X70 pipeline steels

NASA Astrophysics Data System (ADS)

Hwang, Byoungchul; Kim, Young Min; Lee, Sunghak; Kim, Nack J.; Yoo, Jang Yong

2005-07-01

Correlation of rolling conditions, microstructure, and low-temperature toughness of high-toughness X70 pipeline steels was investigated in this study. Twelve kinds of steel specimens were fabricated by vacuum-induction melting and hot rolling, and their microstructures were varied by rolling conditions. Charpy V-notch (CVN) impact test and drop-weight tear test (DWTT) were conducted on the rolled steel specimens in order to analyze low-temperature fracture properties. Charpy impact test results indicated that the energy transition temperature (ETT) was below -100 °C when the finish cooling temperature range was 350 °C to 500 °C, showing excellent low-temperature toughness. The ETT increased because of the formation of bainitic ferrite and martensite at low finish cooling temperatures and because of the increase in effective grain size due to the formation of coarse ferrites at high finish cooling temperatures. Most of the specimens also showed excellent DWTT properties as the percent shear area well exceeded 85 pct, irrespective of finish rolling temperatures or finish cooling temperatures, although a large amount of inverse fracture occurred at some finish cooling temperatures.

Corrosion protection of steel in ammonia/water heat pumps

DOEpatents

Mansfeld, Florian B.; Sun, Zhaoli

2003-10-14

Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

Stress corrosion cracking of duplex stainless steels in caustic solutions

NASA Astrophysics Data System (ADS)

Bhattacharya, Ananya

Duplex stainless steels (DSS) with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, de-salination plants, marine environments, and others. However, many DSS grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfide-containing caustic solutions. Although stress corrosion cracking of duplex stainless steels in chloride solution has been investigated and well documented in the literature but the SCC mechanisms for DSS in caustic solutions were not known. Microstructural changes during fabrication processes affect the overall SCC susceptibility of these steels in caustic solutions. Other environmental factors, like pH of the solution, temperature, and resulting electrochemical potential also influence the SCC susceptibility of duplex stainless steels. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Changes in the DSS microstructure by different annealing and aging treatments were characterized in terms of changes in the ratio of austenite and ferrite phases, phase morphology and intermetallic precipitation using optical micrography, SEM, EDS, XRD, nano-indentation and microhardness methods. These samples were then tested for general and localized corrosion susceptibility and SCC to understand the underlying mechanisms of crack initiation and propagation in DSS in the above-mentioned environments. Results showed that the austenite phase in the DSS is more susceptible to crack initiation and propagation in caustic solutions, which is different from that in the low pH chloride environment where the ferrite phase is the more susceptible phase. This study also showed that microstructural changes in duplex stainless steels due to different heat treatments could affect their SCC

Anaerobic Corrosion of 304 Stainless Steel Caused by the Pseudomonas aeruginosa Biofilm

PubMed Central

Jia, Ru; Yang, Dongqing; Xu, Dake; Gu, Tingyue

2017-01-01

Pseudomonas aeruginosa is a ubiquitous bacterium capable of forming problematic biofilms in many environments. They cause biocorrosion of medical implants and industrial equipment and infrastructure. Aerobic corrosion of P. aeruginosa against stainless steels has been reported by some researchers while there is a lack of reports on anaerobic P. aeruginosa corrosion in the literature. In this work, the corrosion by a wild-type P. aeruginosa (strain PAO1) biofilm against 304 stainless steel (304 SS) was investigated under strictly anaerobic condition for up to 14 days. The anaerobic corrosion of 304 SS by P. aeruginosa was reported for the first time. Results showed that the average sessile cell counts on 304 SS coupons after 7- and 14-day incubations were 4.8 × 107 and 6.2 × 107 cells/cm2, respectively. Scanning electron microscopy and confocal laser scanning microscopy corroborated the sessile cell counts. The X-ray diffraction analysis identified the corrosion product as iron nitride, confirming that the corrosion was caused by the nitrate reducing biofilm. The largest pit depths on 304 SS surfaces after the 7- and 14-day incubations with P. aeruginosa were 3.9 and 7.4 μm, respectively. Electrochemical tests corroborated the pitting data. PMID:29230206

21 CFR 178.3300 - Corrosion inhibitors used for steel or tinplate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Corrosion inhibitors used for steel or tinplate... steel or tinplate. Corrosion inhibitors may be safely used for steel or tinplate intended for use in, or... packaging of steel or tinplate or articles fabricated therefrom: List of substances Limitations...

21 CFR 178.3300 - Corrosion inhibitors used for steel or tinplate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Corrosion inhibitors used for steel or tinplate... steel or tinplate. Corrosion inhibitors may be safely used for steel or tinplate intended for use in, or... packaging of steel or tinplate or articles fabricated therefrom: List of substances Limitations...

Evaluation of pitting corrosion resistance of high-alloyed stainless steels welds for FGD plants in Korea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baek, K.K.; Sung, H.J.; Im, C.S.

1998-12-31

For successful application of high-alloyed stainless steels for Flue Gas Desulfurization (FGD) plants, pitting corrosion resistance of arc welds of N-added 6%Mo austenitic stainless steels (UNS N 08367) and super duplex stainless steels (UNS S 32550) made with various filler metals were evaluated using the Green Death solution. For Gas Tungsten Arc (GTA) and Gas Metal Arc (GMA) welds of N 08367, Critical Pitting Temperature (CPT) of base metal was 65--70 C, whereas weld made by ERNiCrMo-3 filler metal yielded CPT of 50 C. Welds made by ERNiCrMo-10 or ERNiCrMo-4 filler metals showed CPT of 60--65 C and 65--70C, respectively.more » For GTA and GMA welds of S 32550, CPT of welds made by ERNiCrMo-3 was 45--50 C, indicating that the filler metal can provide pitting corrosion resistance matching the S 32550 alloy. Thus, a proper pitting corrosion resistance of weldments of high-alloy stainless steels can be achieved by selecting filler metals having at least +10 higher Pitting Resistance Equivalent Number (PRE{sub N}) value than the base metal regardless of the type of arc welding process. The over-alloyed filler metals would compensate preferential segregation of Cr, MO along the dendrite boundary, which made the dendrite core more susceptible to pitting. Nitrogen addition to the GTA welds of N 08367 made with ERNiCrMo-3 failed to improve pitting corrosion resistance, which was attributed to the precipitation of nitrogen in the weld metal in the form of Nb-nitride.« less

Inhibition of atmospheric corrosion of mild steel by sodium benzoate treatment

NASA Astrophysics Data System (ADS)

Kahraman, Ramazan

2002-02-01

The objective of this study was to evaluate the effectiveness of sodium benzoate as an inhibitor to slow down or prevent atmospheric corrosion/discoloration of the local mild steel during storage in the Arabian Gulf region. Test specimens were prepared from locally produced reinforcing steel products. The inhibitor solution was applied on steel specimens at a concentration of 100 mM for 1 day at room temperature. Wooden exposure racks were used to hold as-received and inhibitor-treated specimens during atmospheric exposure for different periods. Corrosion was evaluated through weight loss determination and electrochemical technique. As expected, the Arabian Gulf atmosphere was corrosive on the as-received local mild steel. On the other hand, treatment of steel with sodium benzoate lowered its corrosion rate during initial days of its exposure to atmosphere. However, atmospheric corrosion inhibition performance of sodium benzoate deteriorated with exposure time after 30 or more days of atmospheric exposure, and the corrosion rates of sodium benzoate-treated specimens reached that of the unprotected specimens at the end of 90 days of atmospheric exposure.

Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

NASA Astrophysics Data System (ADS)

Shi, Jin-jie; Ming, Jing

2017-01-01

Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon (LC) steel and low-alloy (LA) steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

Microbial Iron Respiration Can Protect Steel from Corrosion

PubMed Central

Dubiel, M.; Hsu, C. H.; Chien, C. C.; Mansfeld, F.; Newman, D. K.

2002-01-01

Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

Corrosion protection of galvanized steels by silane-based treatments

NASA Astrophysics Data System (ADS)

Yuan, Wei

The possibility of using silane coupling agents as replacements for chromate treatments was investigated on galvanized steel substrates. In order to understand the influence of deposition parameters on silane film formation, pure zinc substrates were first used as a model for galvanized steel to study the interaction between silane coupling agents and zinc surfaces. The silane films formed on pure zinc substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and atomic force microscopy. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation reactions in aqueous solutions. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is almost independent of the solution dipping time. The molecular orientation of applied silane films is determined by the pH value of applied silane solutions and the isoelectric point of metal substrates. The deposition window in terms of pH value for zinc substrates is between 6.0 and 9.0. The total surface energy of the silane-coated pure zinc substrates decreases with film aging time, the decrease rate, however, is determined by the nature of silane coupling agents. Selected silane coupling agents were applied as prepaint or passivation treatments onto galvanized steel substrates. The corrosion protection provided by these silane-based treatments were evaluated by salt spray test, cyclic corrosion test, electrochemical impedance spectroscopy, and stack test. The results showed that silane coupling agents can possibly be used to replace chromates for corrosion control of galvanized steel substrates. Silane coatings provided by these silane treatments serve mainly as physical barriers. Factors that

Effect of Alternating Current on the Cathodic Protection and Interface Structure of X80 Steel.

PubMed

Wang, Huiru; Du, Cuiwei; Liu, Zhiyong; Wang, Luntao; Ding, De

2017-07-25

This study employs potential-monitoring techniques, cyclic voltammetry tests, alternating current (AC) voltammetry methods, and surface characterization to investigate the AC corrosion of cathodically protected X80 pipeline steel. In a non-passive neutral solution at pH 7.2, a sufficiently negative potential completely protects steel at an AC current density of 100 A/m². In an alkaline solution at pH 9.6, more serious AC corrosion occurs at more negative cathodic protection (CP) potential, whereas without CP the steel suffers negligible corrosion. In addition, the interface capacitance increases with AC amplitude. Based on these results, the AC corrosion mechanisms that function under various conditions are analyzed and described.

Effect of Alternating Current on the Cathodic Protection and Interface Structure of X80 Steel

PubMed Central

Wang, Huiru; Du, Cuiwei; Liu, Zhiyong; Wang, Luntao; Ding, De

2017-01-01

This study employs potential-monitoring techniques, cyclic voltammetry tests, alternating current (AC) voltammetry methods, and surface characterization to investigate the AC corrosion of cathodically protected X80 pipeline steel. In a non-passive neutral solution at pH 7.2, a sufficiently negative potential completely protects steel at an AC current density of 100 A/m2. In an alkaline solution at pH 9.6, more serious AC corrosion occurs at more negative cathodic protection (CP) potential, whereas without CP the steel suffers negligible corrosion. In addition, the interface capacitance increases with AC amplitude. Based on these results, the AC corrosion mechanisms that function under various conditions are analyzed and described. PMID:28773211

Effect of SO2 concentration as an impurity on carbon steel corrosion under subcritical CO2 environment

NASA Astrophysics Data System (ADS)

Mahlobo, MGR; Premlall, K.; Olubambi, PA

2017-12-01

Carbon dioxide (CO2) is considered to be easier to transport over moderate distances when turned into supercritical state (dense phase) than at any other state. Because of this reason, the transportation of CO2 during carbon capture and storage requires CO2 to be at its supercritical state. CO2 temperature profile from different regions causes CO2 to deviate between supercritical and subcritical state (gas/liquid phase). In this study the influence of sulphur dioxide (SO2) on the corrosion of carbon steel was evaluated under different SO2 concentrations (0.5, 1.5 and 5%) in combination with subcritical CO2. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy-Dispersive X-ray Spectroscopy (EDS) were used to characterize the CO2 corrosion product layer formed on the carbon steel surface. The weight loss results showed that corrosion rate increased with SO2 concentration with corrosion rate up to 7.45 mm/year while at 0% SO2 the corrosion rate was 0.067 mm/year.

AC-Induced Bias Potential Effect on Corrosion of Steels

DTIC Science & Technology

2009-02-05

induction, variable conduction Experimental Setup Super- martensitic stainless steel composition Analysis: C Mn Si Cr Ni Mo Cu N Typical 13 Cr ɘ.01 0.6... stainless steel used in pipelines. •Low carbon (ɘ.01): allows the formation of a “soft” martensite that is more resistant than standard martensitic ...Proposed AC Corrosion Models  AC Simulated Corrosion testing  Stainless steel pipe and coating  Cathodic protection  Experimental Setup  Preliminary

Pitting and stress corrosion cracking of stainless steel

NASA Astrophysics Data System (ADS)

Saithala, Janardhan R.

An investigation has been performed to determine the pitting resistance of stainless steels and stress corrosion cracking of super duplex stainless steels in water containing chloride ions from 25 - 170°C. The steels studied are 12% Cr, FV520B, FV566, 304L, Uranus65, 2205, Ferallium Alloy 255, and Zeron 100. All these commercial materials used in very significant industrial applications and suffer from pitting and stress corrosion failures. The design of a new experimental setup using an autoclave enabled potentiodynamic polarisation experiments and slow strain rate tests in dilute environments to be conducted at elevated temperatures. The corrosion potentials were controlled using a three electrode cell with computer controlled potentiostat.The experimental programme to determine pitting potentials was designed to simulate the service conditions experienced in most industrial plants and develop mathematical model equations to help a design engineer in material selection decision. Stress corrosion resistance of recently developed Zeron100 was evaluated in dilute environments to propose a mechanism in chloride solutions at high' temperatures useful for the nuclear and power generation industry. Results have shown the significance of the composition of alloying elements across a wide range of stainless steels and its influence on pitting. Nitrogen and molybdenum added to modern duplex stainless steels was found to be unstable at higher temperatures. The fractographic results obtained using the scanning electron microscope (SEM) has given insight in the initiation of pitting in modem duplex and super duplex stainless steels. A mathematical model has been proposed to predict pitting in stainless steels based on the effect of environmental factors (temperature, chloride concentration, and chemical composition). An attempt has been made to identify the mechanism of SCC in Zeron100 super duplex stainless steel.The proposed empirical models have shown good correlation

Effects of scan rate on the corrosion behavior SS 304 stainless steel in the nanofluid measured by Tafel polarization methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prajitno, Djoko Hadi

The Effects of scan rate on the Tafel polarization curve that is obtained to determine corrosion rate are conducted. The tafel polarization curves are obtained at different scan rates for Stainless Steel 304 in nanofluids contain 0.01 gpl nano particle ZrO{sub 2}. The corrosion stainless steel in nanofluid contains adm+0.01 gpl ZrO{sub 2} nanoparticles at different scan rate was performed by Tafel polarization. The results show that according corrosion potential examination of the stainless steel in nanofluid media 0.01gpl ZrO{sub 2} nanoparticle was actively corroded. The value of cathodic Tafel slope stainless steel in nanofluid at different scan rate relativelymore » unchanged after polarization testing. Mean while the value of anodic Tafel slope stainless steel in nanofluid increase at different scan rate. The results of Tafel polarization technique show that corrosion rate of stainless steel in nanofluid increase with increasing scan rate. X ray diffraction examination of stainless steel after Tafel polarization depict that γ Fe phase is major phase in the surface of alloy.« less

Corrosion Resistance of Stainless Steels in Biodiesel

NASA Astrophysics Data System (ADS)

Román, Alejandra S.; Méndez, Claudia M.; Ares, Alicia E.

The aim of this work was to study the corrosion behavior of stainless steels in biodiesel of vegetal origin, at room temperature, evaluating its properties according to the differences in the structures (austenitic, ferritic and austenitic — ferritic) and compositions of the materials. The biodiesel employed was obtained by industrially manufactured based on soybean oil as main raw material. The stainless steels used as samples for the tests were: AISI 304L, Sea Cure and Duplex 2205. For obtaining the desired data potentiodynamic polarization and weight loss trials were carried out. These studies were complemented by observations using an optical microscope. The weight loss study allowed the identification of low corrosion rates to the three stainless steels studied.

The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hilca, B. R., E-mail: bangkithilca@yahoo.com; Triyono, E-mail: triyonomesin@uns.ac.id

This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO{sub 3}) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate contentmore » as inhibitor.« less

Stress-corrosion susceptibility of highway bridge construction steels. Phase I

DOT National Transportation Integrated Search

1972-04-01

A catalog of steels used in highway bridge construction has been developed. A state-of-the-art survey on the stress-corrosion susceptibility of these steels has been conducted. The types and concentrations of corrosives that can be experienced in the...

Corrosion rate of API 5L Gr. X60 multipurpose steel pipeline under combined effect of water and crude oil

NASA Astrophysics Data System (ADS)

Miao, Jian; Wang, Qiang

2016-09-01

Multipurpose pipeline is often seriously corroded during its service life, and the phenomenon is more prominent once the transportation medium is changed. Electrochemical polarization curves and impedance spectroscopy of the API 5L Gr. X60 steel pipeline's corrosion process in sedimentary water with different ion types and their concentrations have been studied in this work. The results showed that the corrosion rates were found to be 0.00418 and 0.00232 mm/a for pure water and crude oil, respectively. However, for the mixtures of water and crude oil (with water content increased from 0.2 vol% to 10 vol%), the corrosion rate increased consistently and reached a maximum value of 0.15557 mm/a for 10 vol% water in crude oil. The effect of the concentration of various ions, namely, chloride, bicarbonate and sulfate in (oil/water) mixtures on the corrosion rate was characterized by weight-loss method. The results showed that with increasing the ions' concentrations, the corresponding exchange current density increased significantly. The results were further supported by the observations of corrosion morphology using scanning electron microscopy and are helpful in devising guidelines which would help in reducing corrosion in multipurpose transport pipelines involving a change of transported medium during their service life.

Novel Corrosion Inhibitor for Mild Steel in HCl.

PubMed

Al-Amiery, Ahmed A; Kadhum, Abdul Amir H; Alobaidy, Abdul Hameed M; Mohamad, Abu Bakar; Hoon, Pua Soh

2014-01-27

Corrosion inhibitory effects of new synthesized compound namely 5,5'- ((1Z,1'Z)-(1,4-phenylenebis(methanylylidene))bis(azanylylidene))bis(1,3,4-thiadiazole-2-thiol) (PBB) on mild steel in 1.0 M HCl was investigated at different temperatures using open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results showed that PBB inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiencies increased with the concentration of inhibitor, but decreased proportionally with temperature. Changes in impedance parameters suggested the adsorption of PBB on the mild steel surface, leading to the formation of protective films.

Forecasting Corrosion of Steel in Concrete Introducing Chloride Threshold Dependence on Steel Potential

NASA Astrophysics Data System (ADS)

Sanchez, Andrea Nathalie

Corrosion initiates in reinforced concrete structures exposed to marine environments when the chloride ion concentration at the surface of an embedded steel reinforcing bar exceeds the chloride corrosion threshold (CT) value. The value of CT is generally assumed to have a conservative fixed value ranging from 0.2% to - 0.5 % of chloride ions by weight of cement. However, extensive experimental investigations confirmed that C T is not a fixed value and that the value of CT depends on many variables. Among those, the potential of passive steel embedded in concrete is a key influential factor on the value of CT and has received little attention in the literature. The phenomenon of a potential-dependent threshold (PDT) permits accounting for corrosion macrocell coupling between active and passive steel assembly components in corrosion forecast models, avoiding overly conservative long-term damage projections and leading to more efficient design. The objectives of this investigation was to 1) expand by a systematic experimental assessment the knowledge and data base on how dependent the chloride threshold is on the potential of the steel embedded in concrete and 2) introduce the chloride threshold dependence on steel potential as an integral part of corrosion-related service life prediction of reinforced concrete structures. Experimental assessments on PDT were found in the literature but for a limited set of conditions. Therefore, experiments were conducted with mortar and concrete specimens and exposed to conditions more representative of the field than those previously available. The experimental results confirmed the presence of the PDT effect and provided supporting information to use a value of -550 mV per decade of Cl- for the cathodic prevention slope betaCT, a critical quantitative input for implementation in a practical model. A refinement of a previous corrosion initiation-propagation model that incorporated PDT in a partially submerged reinforced concrete

Hot Corrosion Behavior of Stainless Steel with Al-Si/Al-Si-Cr Coating

NASA Astrophysics Data System (ADS)

Fu, Guangyan; Wu, Yongzhao; Liu, Qun; Li, Rongguang; Su, Yong

2017-03-01

The 1Cr18Ni9Ti stainless steel with Al-Si/Al-Si-Cr coatings is prepared by slurry process and vacuum diffusion, and the hot corrosion behavior of the stainless steel with/without the coatings is studied under the condition of Na2SO4 film at 950 °C in air. Results show that the corrosion kinetics of stainless steel, the stainless steel with Al-Si coating and the stainless steel with Al-Si-Cr coating follow parabolic laws in several segments. After 24 h corrosion, the sequence of the mass gain for the three alloys is the stainless steel with Al-Si-Cr coating < the stainless steel with Al-Si coating < the stainless steel without any coating. The corrosion products of the three alloys are layered. Thereinto, the corrosion products of stainless steel without coating are divided into two layers, where the outside layer contains a composite of Fe2O3 and FeO, and the inner layer is Cr2O3. The corrosion products of the stainless steel with Al-Si coating are also divided into two layers, of which the outside layer mainly consists of Cr2O3, and the inner layer is mainly SiO2. The corrosion film of the stainless steel with Al-Si-Cr coating is thin and dense, which combines well with substrate. Thereinto, the outside layer is mainly Cr2O3, and the inside layer is Al2O3. In the matrix of all of the three alloys, there exist small amount of sulfides. Continuous and protective films of Cr2O3, SiO2 and Al2O3 form on the surface of the stainless steel with Al-Si and Al-Si-Cr coatings, which prevent further oxidation or sulfide corrosion of matrix metals, and this is the main reason for the much smaller mass gain of the two alloys than that of the stainless steel without any coatings in the 24 h hot corrosion process.

Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions

PubMed Central

Yang, Yuanfeng; Joshi, Gaurav R.; Akid, Robert

2015-01-01

The aim of this research was to investigate the influence of metallurgy on the corrosion behaviour of separate weld zone (WZ) and parent plate (PP) regions of X65 pipeline steel in a solution of deionised water saturated with CO2, at two different temperatures (55 °C and 80 °C) and at initial pH~4.0. In addition, a non-electrochemical immersion experiment was also performed at 80 °C in CO2, on a sample portion of X65 pipeline containing part of a weld section, together with adjacent heat affected zones (HAZ) and parent material. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion behaviour of the separate weld and parent plate samples. This study seeks to understand the significance of the different microstructures within the different zones of the welded X65 pipe in CO2 environments on corrosion performance; with particular attention given to the formation of surface scales; and their composition/significance. The results obtained from grazing incidence X-ray diffraction (GIXRD) measurements suggest that, post immersion, the parent plate substrate is scale free, with only features arising from ferrite (α-Fe) and cementite (Fe3C) apparent. In contrast, at 80 °C, GIXRD from the weld zone substrate, and weld zone/heat affected zone of the non-electrochemical sample indicates the presence of siderite (FeCO3) and chukanovite (Fe2CO3(OH)2) phases. Scanning Electron Microscopy (SEM) on this surface confirmed the presence of characteristic discrete cube-shaped crystallites of siderite together with plate-like clusters of chukanovite.

Active corrosion protection performance of an epoxy coating applied on the mild steel modified with an eco-friendly sol-gel film impregnated with green corrosion inhibitor loaded nanocontainers

NASA Astrophysics Data System (ADS)

Izadi, M.; Shahrabi, T.; Ramezanzadeh, B.

2018-05-01

In this study the corrosion resistance, active protection, and cathodic disbonding performance of an epoxy coating were improved through surface modification of steel by a hybrid sol-gel system filled with green corrosion inhibitors loaded nanocontainer as intermediate layer on mild steel substrate. The green inhibitor loaded nanocontainers (GIN) were used to induce active inhibition performance in the protective coating system. The corrosion protection performance of the coated panels was investigated by electrochemical impedance spectroscopy (EIS), salt spray, and cathodic disbonding tests. It was observed that the corrosion inhibition performance of the coated mild steel panels was significantly improved by utilization of active multilayer coating system. The inhibitor release from nanocontainers at the epoxy-silane film/steel interface resulted in the anodic and cathodic reactions restriction, leading to the lower coating delamination from the substrate and corrosion products progress. Also, the active inhibition performance of the coating system was approved by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDS) analysis on the panels with artificial defects. The inhibitive agents were released to the scratch region and blocked the active sites on the metal surface.

Evaluation and control of environmental corrosion for aluminum and steel alloys

NASA Technical Reports Server (NTRS)

Franklin, D. B.

1977-01-01

Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

Research on A3 steel corrosion behavior of basic magnesium sulfate cement

NASA Astrophysics Data System (ADS)

Xing, Sainan; Wu, Chengyou; Yu, Hongfa; Jiang, Ningshan; Zhang, Wuyu

2017-11-01

In this paper, Tafel polarization technique is used to study the corrosion behavior of A3 steel basic magnesium sulfate, and then analyzing the ratio of raw materials cement, nitrites rust inhibitor and wet-dry cycle of basic magnesium sulfate corrosion of reinforced influence, and the steel corrosion behavior of basic magnesium sulfate compared with magnesium oxychloride cement and Portland cement. The results show that: the higher MgO/MgSO4 mole ratio will reduce the corrosion rate of steel; Too high and too low H2O/MgSO4 mole ratio may speed up the reinforcement corrosion effect; Adding a small amount of nitrite rust and corrosion inhibitor, not only can obviously reduce the alkali type magnesium sulfate in the early hydration of cement steel bar corrosion rate, but also can significantly reduce dry-wet circulation under the action of alkali type magnesium sulfate cement corrosion of reinforcement effect. Basic magnesium sulfate cement has excellent ability to protect reinforced, its long-term corrosion of reinforcement effect and was equal to that of Portland cement. Basic magnesium sulfate corrosion of reinforced is far below the level in the MOC in the case.

A New Green Ionic Liquid-Based Corrosion Inhibitor for Steel in Acidic Environments.

PubMed

Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdel Rahman O

2015-06-17

This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS) and oleylammonium tosylate (OA-TS) for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements, scanning electron microscope (SEM), Energy dispersive X-rays (EDX) analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface.

Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

PubMed Central

Shi, Shih-Chen; Su, Chieh-Chang

2016-01-01

The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives. PMID:28773733

The effect of O2 content on the corrosion behaviour of X65 and 5Cr in water-containing supercritical CO2 environments

NASA Astrophysics Data System (ADS)

Hua, Yong; Barker, Richard; Neville, Anne

2015-11-01

The general and localized corrosion behaviour of X65 carbon steel and 5Cr low alloy steel were evaluated in a water-saturated supercritical CO2 environment in the presence of varying concentrations of O2. Experiments were performed at a temperature of 35 °C and a pressure of 80 bar to simulate the conditions encountered during CO2 transport and injection. Results indicated that increasing O2 concentration from 0 to 1000 ppm caused a progressive reduction in the general corrosion rate, but served to increase the extent of localized corrosion observed on both materials. Pitting (or localized attack) rates for X65 ranged between 0.9 and 1.7 mm/year, while for 5Cr rose from 0.3 to 1.4 mm/year as O2 concentration was increased from 0 to 1000 ppm. General corrosion rates were over an order of magnitude lower than the pitting rates measured. Increasing O2 content in the presence of X65 and 5Cr suppressed the growth of iron carbonate (FeCO3) on the steel surface and resulted in the formation of a corrosion product consisting mainly of iron oxide (Fe2O3). 5Cr was shown to offer more resistance to pitting corrosion in comparison to X65 steel over the conditions tested. At concentrations of O2 above 500 ppm 5Cr produced general corrosion rates less than 0.04 mm/year, which were half that recorded for X65. The improved corrosion resistance of 5Cr was believed to be at least partially attributed to the formation of a Cr-rich film on the steel surface which was shown using X-ray photoelectron spectroscopy to contain chromium oxide (Cr2O3) and chromium hydroxide (Cr(OH)3). A final series of tests conducted with the addition of 1000 ppm O2 in under-saturated conditions (water content below solubility limit) revealed that no corrosion was observed when the water content was below 1200 ppm for both materials.

Corrosion Behavior of Weathering Steel Under Thin Electrolyte Layer at Different Relative Humidity

NASA Astrophysics Data System (ADS)

Xia, Yan; Liu, Pan; Zhang, Jianqing; Cao, Fahe

2018-01-01

The corrosion behavior of weathering steel under thin electrolyte layer (TEL) at different relative humidity (RH) was investigated by cathodic polarization, electrochemical impedance spectroscopy, electrochemical noise, SEM/EDS, XRD and Raman spectroscopy. The results indicate that during the initial stage, the corrosion rate increases as the RH decreases when the initial thickness of TEL is above 100 μm. During the middle and final corrosion stages, the corrosion behavior of weathering steel is influenced by RH, the initial thickness of TEL and corrosion product. The TEL corrosion is divided into three types, and a weathering steel corrosion model under TEL and bulk solution is also proposed.

Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste

NASA Astrophysics Data System (ADS)

Duffó, G. S.; Farina, S. B.; Schulz, F. M.

2013-07-01

Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 μm/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 μm/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

Characterization and prediction of carbon steel corrosion in diluted seawater containing pentaborate

NASA Astrophysics Data System (ADS)

Fukaya, Yuichi; Watanabe, Yutaka

2018-01-01

This study addresses the influence of Na2B10O16, which may be used for criticality control of fuel debris in the Fukushima Daiichi Nuclear Power Station, on the corrosion behavior of carbon steel in diluted artificial seawater. The corrosion forms of carbon steel were categorized as uniform corrosion, localized corrosion, and passivity based on the balance between the dilution ratio of artificial seawater and the concentration of Na2B10O16. The changes in corrosion forms were arranged on a water quality region map. Passivity was maintained by adding 3.7 × 10-2 M or more of Na2B10O16 to artificial seawater with a dilution ratio of 100-fold or more. The criticality control of the fuel debris and corrosion mitigation of the carbon steel components may be achieved simultaneously in the water quality. The prediction of the corrosion form of carbon steel was attempted by the extended Larson-Skold Index (LSI) = ([Cl-] + 2[SO42-])/([HCO3-] + 2[B10O162-]). However, because the passivating action of B10O162- was remarkably stronger than that of HCO3-, the prediction was difficult under the simple addition of equivalent concentrations. The localized corrosion of carbon steel under the addition of Na2B10O16 preferentially occurred from the crevices of the test specimens, as was the case in stainless steel.

Investigating pitting in X65 carbon steel using potentiostatic polarisation

NASA Astrophysics Data System (ADS)

Mohammed, Sikiru; Hua, Yong; Barker, R.; Neville, A.

2017-11-01

Although pitting corrosion in passive materials is generally well understood, the growth of surface pits in actively-corroding materials has received much less attention to date and remains poorly understood. One of the key challenges which exists is repeatedly and reliably generating surface pits in a practical time-frame in the absence of deformation and/or residual stress so that studies on pit propagation and healing can be performed. Another pertinent issue is how to evaluate pitting while addressing general corrosion in low carbon steel. In this work, potentiostatic polarisation was employed to induce corrosion pits (free from deformation or residual stress) on actively corroding X65 carbon steel. The influence of applied potential (50 mV, 100 mV and 150 mV vs open circuit potential) was investigated over 24 h in a CO2-saturated, 3.5 wt.% NaCl solution at 30 °C and pH 3.8. Scanning electron microscopy (SEM) was utilised to examine pits, while surface profilometry was conducted to measure pit depth as a function of applied potential over the range considered. Analyses of light pitting (up to 120 μm) revealed that pit depth increased linearly with increase in applied potential. This paper relates total pit volume (measured using white light interferometry) to dissipated charge or total mass loss (using the current response for potentiostatic polarisation in conjunction with Faraday's law). By controlling the potential of the surface (anodic) the extent of pitting and general corrosion could be controlled. This allowed pits to be evaluated for their ability to continue to propagate after the potentiostatic technique was employed. Linear growth from a depth of 70 μm at pH 3.8, 80 °C was demonstrated. The technique offers promise for the study of inhibition of pitting.

Detecting Corrosion Resistance of Coated Steel Rebars by Electrochemical Technique (eis)

NASA Astrophysics Data System (ADS)

Ryou, J.; Shah, S.

Electrochemical impedance spectroscopy (EIS) is one of the electrochemical techniques used in materials science. The present measurements are used to evaluate the corrosion resistance of new types of coated steel rebar used in reinforced concrete. In this study, Si-based coating materials are used and evaluated, because adding Si to metals and alloys, including steel, generally increases their corrosion, oxidation, and erosion resistance. The result suggests that electrochemical impedance spectroscopy may be useful for monitoring corrosion activity on coated steel rebars. Based upon impedance changes, it appears that the silicon powder coating bonds well to the steel, and that the coating has a good performance.

Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

DOEpatents

Park, Jong-Hee; Natesan, Krishnamurti; Rink, David L.

2010-03-16

An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

Corrosion of carbon steels, stainless steels, and titanium in aqueous lithium bromide solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guinon, J.L.; Garcia-Anton, J.; Perez-Herranz, V.

1994-03-01

Effects of lithium bromide (LiBr) concentration, pH, temperature, exposure time, and the action of some inhibitors on corrosion of several carbon (C) steels, stainless steels (SS), and a titanium (Ti) alloy were studied. Corrosion rates were determined by the polarization resistance method and compared to rates determined by weight-loss measurements. Pitting potentials (E[sub p]) were evaluated in neutral LiBr solution and with different inhibitors. Pit density and average pit depth depended on the metal tested, with lowest values for Ti, the next lowest values for type 316 SS (UNS S31600), and the highest values for UNS G41350 tempered steel.

Composition-controlled active-passive transition and corrosion behavior of Fe-Cr(Mo)-Zr-B bulk amorphous steels

NASA Astrophysics Data System (ADS)

Si, Jiajia; Wu, Yidong; Wang, Tan; Liu, Yanhui; Hui, Xidong

2018-07-01

Various corrosive environments in daily life and industry have put forward high requirement on corrosion resistance of metals, especially steels. Unlike the strict demand in Cr content of crystalline stainless steels, amorphous steels (ASs) with lower Cr content can be endowed with outstanding corrosion resistance, while the intrinsic mechanism is not fully understood. Herein, we present a novel Fe92-x-y-zCrxMoyZr8Bz (6 ≤ x ≤ 40, 0 ≤ y ≤ 22, and 12 ≤ z ≤ 18) bulk amorphous steel (BAS) forming system and reveal the synergistic effect of Cr and Mo in determining the chemical stability of oxide films. It has been found the Fe92-x-zCrxZr8Bz BASs with 1 mm in diameter display a Cr-controlling active-passive transition at the Cr threshold of ∼25% in 1 M hydrochloric acid. When adding minor Mo into the BASs, the Cr threshold can be remarkably reduced by forming favorable hexavalent Mo oxides. The generation of Mo6+ is facilitated by atomic selective dissolution at the interface and can promote the passivation. In contrast, when the Cr content of the Mo-doped glasses exceeds 25%, few Mo6+ oxides would produce as the prior formation of protective passive films inhibits the further oxidation of Mo. Therefore, manipulating the active-passive transition properly is crucial to designing ASs with high stainlessness.

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

PubMed

Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

2011-06-01

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

Identification of corrosion product on medium carbon steel under the exposure of Banda Aceh’s atmosphere

NASA Astrophysics Data System (ADS)

Thalib, Sulaiman; Ikhsan, Muharil; Fonna, Syarizal; Huzni, Syifaul; Ridha, Syahrir

2018-05-01

This research was conducted to study the form of corrosion products of medium carbon steel under the exposure of Banda Aceh’s atmosphere. The medium carbon steel samples which the size based on ASTM G 50 were exposed in open areas around the Engineering Faculty, Syiah Kuala University, Darussalam - Banda Aceh, Aceh province, Indonesia. The study was carried out from January through December 2016. The corrosion product formed on the surface of the samples was studied using X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) method. Measurements of weight loss due to atmospheric corrosion as a basis for calculating corrosion rates was referring to ASTM G1. Corrosion product found based on XRD analysis was lepidocrocite (FeO2, γ-FeOOH) and goethite (FeO2, α-FeOOH). The results agreed with SEM analysis that also indicates to lepidocrocite and goethite. The corrosion rate for twelve months showed that the highest rate occurs in the period of March-April that was 0.024 mpy. During twelve months exposure, the corrosion products consist of lepidocrocite and goethite. Significant changes began to occur in the eighth month, where the product of corrosion was almost entirely goethite.

Corrosion behaviour and biocorrosion of galvanized steel water distribution systems.

PubMed

Delaunois, F; Tosar, F; Vitry, V

2014-06-01

Galvanized steel tubes are a popular mean for water distribution systems but suffer from corrosion despite their zinc or zinc alloy coatings. First, the quality of hot-dip galvanized (HDG) coatings was studied. Their microstructure, defects, and common types of corrosion were observed. It was shown that many manufactured tubes do not reach European standard (NBN EN 10240), which is the cause of several corrosion problems. The average thickness of zinc layer was found at 41μm against 55μm prescribed by the European standard. However, lack of quality, together with the usual corrosion types known for HDG steel tubes was not sufficient to explain the high corrosion rate (reaching 20μm per year versus 10μm/y for common corrosion types). Electrochemical tests were also performed to understand the corrosion behaviours occurring in galvanized steel tubes. Results have shown that the limiting step was oxygen diffusion, favouring the growth of anaerobic bacteria in steel tubes. EDS analysis was carried out on corroded coatings and has shown the presence of sulphur inside deposits, suggesting the likely bacterial activity. Therefore biocorrosion effects have been investigated. Actually sulphate reducing bacteria (SRB) can reduce sulphate contained in water to hydrogen sulphide (H2S), causing the formation of metal sulphides. Although microbial corrosion is well-known in sea water, it is less investigated in supply water. Thus, an experimental water main was kept in operation for 6months. SRB were detected by BART tests in the test water main. Copyright © 2014 Elsevier B.V. All rights reserved.

In-Plant Corrosion Study of Steels in Distillery Effluent Treatment Plant

NASA Astrophysics Data System (ADS)

Ram, Chhotu; Sharma, Chhaya; Singh, A. K.

2015-05-01

The present study deals with corrosion and performance of steels observed in an effluent treatment plant (ETP) of a distillery. For this purpose, the metal coupons were exposed in primary (untreated effluent) and secondary tank (anaerobic treatment effluent) of the ETP. The extent of attack has been correlated with the composition of the effluent with the help of laboratory immersion and electrochemical tests. Untreated distillery effluent found to be more corrosive than the anaerobic-treated effluents and is assigned due to chloride, phosphate, calcium, nitrate, and nitrite ions, which enhances corrosivity at acidic pH. Mild steel showed highest uniform and localized corrosion followed by stainless steels 304L and 316L and lowest in case of duplex 2205.

The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Sapiro, David O.

This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron

High-temperature protection of steel goods from gas corrosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerasimov, V.V.; Porfir`eva, R.T.; Peskov, A.V.

The feasibility of using phosphorus-containing compounds to activate the thermal diffusion impregnation of steels with aluminum was explored and substantiated by experiment. Volatile phosphorus formed from the thermal destruction of the phosphorus-containing substances and the resulting Al/P-type complexes, which provide a gas-transportation medium to take the aluminum to the article surface, were instrumental in the mechanism. The resultant thermal diffusion coatings enabled steel to be safely protected from gas corrosion at a temperature of 950{degrees}C. As a result of research on the structure of the protective layer using electron microscopy and X-ray phase analysis, coatings formed using a mixture containingmore » 1 wt.% iron glycerophosphate exhibited the optimum operating characteristics.« less

Impact of saline aquifer water on surface and shallow pit corrosion of martensitic stainless steels during exposure to CO2 environment (CCS)

NASA Astrophysics Data System (ADS)

Pfennig, Anja; Kranzmann, Axel

2018-05-01

Pipe steels suitable for carbon capture and storage technology (CCS) require resistance against the corrosive environment of a potential CCS-site, e.g. heat, pressure, salinity of the aquifer, CO2-partial pressure. Samples of different mild and high alloyed stainless injection-pipe steels partially heat treated: 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 as well as X5CrNiCuNb16-4 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in a CO2-saturated synthetic aquifer environment similar to possible geological on-shore CCS-sites in the northern German Basin. Main corrosion products are FeCO3 and FeOOH. Corrosion rates obtained at 100 bar are generally much lower than those measured at ambient pressure. Highest surface corrosion rates are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4 in the vapour phase at ambient pressure. At 100 bar the highest corrosion rates are 0.01 mm/year for 42CrMo4, X20Cr13 (liquid phase), X46Cr13 and less than 0.01 mm/year for X35CrMo4 and X5CrNiCuNb16-4 after 8000 h of exposure with no regard to atmosphere. Martensitic microstructure offers good corrosion resistance.

Corrosion performance of zinc coated steel in seawater environment

NASA Astrophysics Data System (ADS)

Liu, Shuan; Zhao, Xia; Zhao, Haichao; Sun, Huyuan; Chen, Jianmin

2017-03-01

Considering the continuous exploitation of marine resources, it is very important to study the anticorrosion performance and durability of zinc coated streel (ZCS) because its increasing use as reinforcements in seawater. Tafel polarization curves and linear polarization curves combined with electrochemical impedance spectroscopy (EIS) were employed to evaluate the corrosion performance of ZCS at Qingdao test station during long-term immersion in seawater. The results indicated that the corrosion rate of the ZCS increased obviously with immersion time in seawater. The corrosion products that formed on the zinc coated steel were loose and porous, and were mainly composed of Zn5(OH)8Cl2, Zn5(OH)6(CO3)2, and ZnO. Pitting corrosion occurred on the steel surface in neutral seawater, and the rate of ZCS corrosion decreased with increasing pH.

Effect of nanograin-boundary networks generation on corrosion of carburized martensitic stainless steel.

PubMed

Boonruang, Chatdanai; Thong-On, Atcharawadi; Kidkhunthod, Pinit

2018-02-02

Martensitic stainless steel parts used in carbonaceous atmosphere at high temperature are subject to corrosion which results in a large amount of lost energy and high repair and maintenance costs. This work therefore proposes a model for surface development and corrosion mechanism as a solution to reduce corrosion costs. The morphology, phase, and corrosion behavior of steel are investigated using GIXRD, XANES, and EIS. The results show formation of nanograin-boundary networks in the protective layer of martensitic stainless steel. This Cr 2 O 3 -Cr 7 C 3 nanograin mixture on the FeCr 2 O 4 layer causes ion transport which is the main reason for the corrosion reaction during carburizing of the steel. The results reveal the rate determining steps in the corrosion mechanism during carburizing of steel. These steps are the diffusion of uncharged active gases in the stagnant-gas layer over the steel surface followed by the conversion of C into C 4- and O into O 2- at the gas-oxide interface simultaneously with the migration of Cr 3+ from the metal-oxide interface to the gas-oxide interface. It is proposed that previous research on Al 2 O 3 coatings may be the solution to producing effective coatings that overcome the corrosion challenges discussed in this work.

Marine Atmospheric Corrosion of Carbon Steel: A Review.

PubMed

Alcántara, Jenifer; Fuente, Daniel de la; Chico, Belén; Simancas, Joaquín; Díaz, Iván; Morcillo, Manuel

2017-04-13

The atmospheric corrosion of carbon steel is an extensive topic that has been studied over the years by many researchers. However, until relatively recently, surprisingly little attention has been paid to the action of marine chlorides. Corrosion in coastal regions is a particularly relevant issue due the latter's great importance to human society. About half of the world's population lives in coastal regions and the industrialisation of developing countries tends to concentrate production plants close to the sea. Until the start of the 21st century, research on the basic mechanisms of rust formation in Cl - -rich atmospheres was limited to just a small number of studies. However, in recent years, scientific understanding of marine atmospheric corrosion has advanced greatly, and in the authors' opinion a sufficient body of knowledge has been built up in published scientific papers to warrant an up-to-date review of the current state-of-the-art and to assess what issues still need to be addressed. That is the purpose of the present review. After a preliminary section devoted to basic concepts on atmospheric corrosion, the marine atmosphere, and experimentation on marine atmospheric corrosion, the paper addresses key aspects such as the most significant corrosion products, the characteristics of the rust layers formed, and the mechanisms of steel corrosion in marine atmospheres. Special attention is then paid to important matters such as coastal-industrial atmospheres and long-term behaviour of carbon steel exposed to marine atmospheres. The work ends with a section dedicated to issues pending, noting a series of questions in relation with which greater research efforts would seem to be necessary.

Marine Atmospheric Corrosion of Carbon Steel: A Review

PubMed Central

Alcántara, Jenifer; de la Fuente, Daniel; Chico, Belén; Simancas, Joaquín; Díaz, Iván; Morcillo, Manuel

2017-01-01

The atmospheric corrosion of carbon steel is an extensive topic that has been studied over the years by many researchers. However, until relatively recently, surprisingly little attention has been paid to the action of marine chlorides. Corrosion in coastal regions is a particularly relevant issue due the latter’s great importance to human society. About half of the world’s population lives in coastal regions and the industrialisation of developing countries tends to concentrate production plants close to the sea. Until the start of the 21st century, research on the basic mechanisms of rust formation in Cl−-rich atmospheres was limited to just a small number of studies. However, in recent years, scientific understanding of marine atmospheric corrosion has advanced greatly, and in the authors’ opinion a sufficient body of knowledge has been built up in published scientific papers to warrant an up-to-date review of the current state-of-the-art and to assess what issues still need to be addressed. That is the purpose of the present review. After a preliminary section devoted to basic concepts on atmospheric corrosion, the marine atmosphere, and experimentation on marine atmospheric corrosion, the paper addresses key aspects such as the most significant corrosion products, the characteristics of the rust layers formed, and the mechanisms of steel corrosion in marine atmospheres. Special attention is then paid to important matters such as coastal-industrial atmospheres and long-term behaviour of carbon steel exposed to marine atmospheres. The work ends with a section dedicated to issues pending, noting a series of questions in relation with which greater research efforts would seem to be necessary. PMID:28772766

Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

NASA Astrophysics Data System (ADS)

Moran Yanez, Luis M.

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-11

...)] Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis of the record... revocation of the countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion-resistant carbon steel flat products from Germany and Korea...

Characterization of corrosion scale formed on stainless steel delivery pipe for reclaimed water treatment.

PubMed

Cui, Yong; Liu, Shuming; Smith, Kate; Yu, Kanghua; Hu, Hongying; Jiang, Wei; Li, Yuhong

2016-01-01

To reveal corrosion behavior of stainless steel delivery pipe used in reclaimed water treatment, this research focused on the morphological, mineralogical and chemical characteristics of stainless steel corrosion scale and corroded passive film. Corrosion scale and coupon samples were taken from a type 304 pipe delivering reclaimed water to a clear well in service for more than 12 years. Stainless steel corrosion scales and four representative pipe coupons were investigated using mineralogy and material science research methods. The results showed corrosion scale was predominantly composed of goethite, lepidocrocite, hematite, magnetite, ferrous oxide, siderite, chrome green and chromite, the same as that of corroded pipe coupons. Hence, corrosion scale can be identified as podiform chromite deposit. The loss of chromium in passive film is a critical phenomenon when stainless steel passive film is damaged by localized corrosion. This may provide key insights toward improving a better comprehension of the formation of stainless steel corrosion scale and the process of localized corrosion. The localized corrosion behavior of stainless steel is directly connected with reclaimed water quality parameters such as residual chlorine, DO, Cl(-) and SO4(2-). In particular, when a certain amount of residual chlorine in reclaimed water is present as an oxidant, ferric iron is the main chemical state of iron minerals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stress corrosion cracking evaluation of precipitation-hardening stainless steel

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Nelson, E. E.

1970-01-01

Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

Effect of free Cr content on corrosion behavior of 3Cr steels in a CO2 environment

NASA Astrophysics Data System (ADS)

Li, Wei; Xu, Lining; Qiao, Lijie; Li, Jinxu

2017-12-01

The corrosion behavior of 3Cr steels with three microstructures (martensite, bainite, combined ferrite and pearlite) in simulated oil field formation water with a CO2 partial pressure of 0.8 MPa was investigated. The relationships between Cr concentrations in corrosion scales and corrosion rates were studied. The precipitated phases that contained Cr were observed in steels of different microstructures, and free Cr content levels were compared. The results showed that steel with the martensite microstructure had the highest free Cr content, and thus had the highest corrosion resistance. The free Cr content of bainite steel was lower than that of martensite steel, and the corrosion rate of bainite steel was higher than that of martensite steel. Because large masses of Cr were combined in ferrite and pearlite steel, the corrosion rates of ferrite and pearlite steel were the highest. Free Cr content in steel affects its corrosion behavior greatly.

Anodic Oxidation of Carbon Steel at High Current Densities and Investigation of Its Corrosion Behavior

NASA Astrophysics Data System (ADS)

Fattah-Alhosseini, Arash; Khan, Hamid Yazdani

2017-06-01

This work aims at studying the influence of high current densities on the anodization of carbon steel. Anodic protective coatings were prepared on carbon steel at current densities of 100, 125, and 150 A/dm2 followed by a final heat treatment. Coatings microstructures and morphologies were analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the uncoated carbon steel substrate and the anodic coatings were evaluated in 3.5 wt pct NaCl solution through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that the anodic oxide coatings which were prepared at higher current densities had thicker coatings as a result of a higher anodic forming voltage. Therefore, the anodized coatings showed better anti-corrosion properties compared to those obtained at lower current densities and the base metal.

Corrosion behavior of steels in liquid lead bismuth with low oxygen concentrations

NASA Astrophysics Data System (ADS)

Kurata, Yuji; Futakawa, Masatoshi; Saito, Shigeru

2008-02-01

Corrosion tests in pots were conducted to elucidate corrosion behavior of various steels in liquid lead-bismuth for 3000 h under the condition of an oxygen concentration of 5 × 10 -8 wt% at 450 °C and an oxygen concentration of 3 × 10 -9 wt% at 550 °C, respectively. Significant corrosion was not observed at 450 °C for ferritic/martensitic steels, F82H, Mod.9Cr-1Mo steel, 410SS, 430SS except 2.25Cr-1Mo steel. Pb-Bi penetration into steels and dissolution of elements into Pb-Bi were severe at 550 °C even for ferritic/martensitic steels. Typical dissolution attack occurred for pure iron both at 550 °C without surface Fe 3O 4 and at 450 °C with a thin Fe 3O 4 film. Ferritization due to dissolution of Ni and Cr, and Pb-Bi penetration were recognized for austenitic stainless steels, 316SS and 14Cr-16Ni-2Mo steel at both temperatures of 450 °C and 550 °C. The phenomena were mitigated for 18Cr-20Ni-5Si steel. In some cases oxide films could not be a corrosion barrier in liquid lead-bismuth.

In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

PubMed

Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

2008-11-01

The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications.

Effect of Surface Modification on Corrosion Resistance of Uncoated and DLC Coated Stainless Steel Surface

NASA Astrophysics Data System (ADS)

Scendo, Mieczyslaw; Staszewska-Samson, Katarzyna

2017-08-01

Corrosion resistance of 4H13 stainless steel (EN-X46Cr13) surface uncoated and coated with an amorphous hydrogenated carbon (a-C:H) film [diamond-like carbon (DLC)] in acidic chloride solution was investigated. The DLC films were deposited on steel surface by a plasma deposition, direct current discharge (PDCD) method. The Fourier transform infrared (FTIR) was used to determine the chemical groups existing on DLC films. The surface of the specimens was observed by a scanning electron microscope (SEM). The tribological properties of the both materials were examined using a ball-on disk tribometer. The microhardness (HV) of diamond-like carbon film increased over five times in relation to the 4H13 stainless steel without of DLC coating. Oxidation kinetic parameters were determined by gravimetric and electrochemical methods. The high value of polarization resistance indicates that the DLC film on substrate was characterized by low electrical conductivity. The corrosion rate of 4H13 stainless steel with of DLC film decreased about eight times in relation to uncoated surface of 4H13 stainless steel.

Steel reinforcement corrosion detection with coaxial cable sensors

NASA Astrophysics Data System (ADS)

Muchaidze, Iana; Pommerenke, David; Chen, Genda

2011-04-01

Corrosion processes in the steel reinforced structures can result in structural deficiency and with time create a threat to human lives. Millions of dollars are lost each year because of corrosion. According to the U. S. Federal Highway Administration (FHWA) the average annual cost of corrosion in the infrastructure sector by the end of 2002 was estimated to be $22.6 billion. Timely remediation/retrofit and effective maintenance can extend the structure's live span for much less expense. Thus the considerable effort should be done to deploy corrosion monitoring techniques to have realistic information on the location and the severity of damage. Nowadays commercially available techniques for corrosion monitoring require costly equipment and certain interpretational skills. In addition, none of them is designed for the real time quality assessment. In this study the crack sensor developed at Missouri University of Science and Technology is proposed as a distributed sensor for real time corrosion monitoring. Implementation of this technology may ease the pressure on the bridge owners restrained with the federal budget by allowing the timely remediation with the minimal financial and labor expenses. The sensor is instrumented in such a way that the location of any discontinuity developed along its length can be easily detected. When the sensor is placed in immediate vicinity to the steel reinforcement it is subjected to the same chemical process as the steel reinforcement. And corrosion pitting is expected to develop on the sensor exactly at the same location as in the rebar. Thus it is expected to be an effective tool for active corrosion zones detection within reinforced concrete (RC) members. A series of laboratory tests were conducted to validate the effectiveness of the proposed methodology. Nine sensors were manufactured and placed in the artificially created corrosive environment and observed over the time. To induce accelerated corrosion 3% and 5% Na

The Passive Film Growth Mechanism of New Corrosion-Resistant Steel Rebar in Simulated Concrete Pore Solution: Nanometer Structure and Electrochemical Study

PubMed Central

Jiang, Jin-yang; Wang, Danqian; Chu, Hong-yan; Ma, Han; Liu, Yao; Gao, Yun; Shi, Jinjie; Sun, Wei

2017-01-01

An elaborative study was carried out on the growth mechanism and properties of the passive film for a new kind of alloyed corrosion-resistant steel (CR steel). The passive film naturally formed in simulated concrete pore solutions (pH = 13.3). The corrosion resistance was evaluated by various methods including open circuit potential (OCP), linear polarization resistance (LPR) measurements, and electrochemical impedance spectroscopy (EIS). Meanwhile, the 2205 duplex stainless steel (SS steel) was evaluated for comparison. Moreover, the passive film with CR steel was studied by means of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Atomic Force Microscope (AFM), and the Mott‑Schottky approach. The results showed that the excellent passivity of CR steel could be detected in a high alkaline environment. The grain boundaries between the fine passive film particles lead to increasing Cr oxide content in the later passivation stage. The filling of cation vacancies in the later passivation stage as well as the orderly crystalized inner layer contributed to the excellent corrosion resistance of CR steel. A passive film growth model for CR steel was proposed. PMID:28772772

The Passive Film Growth Mechanism of New Corrosion-Resistant Steel Rebar in Simulated Concrete Pore Solution: Nanometer Structure and Electrochemical Study.

PubMed

Jiang, Jin-Yang; Wang, Danqian; Chu, Hong-Yan; Ma, Han; Liu, Yao; Gao, Yun; Shi, Jinjie; Sun, Wei

2017-04-14

An elaborative study was carried out on the growth mechanism and properties of the passive film for a new kind of alloyed corrosion-resistant steel (CR steel). The passive film naturally formed in simulated concrete pore solutions (pH = 13.3). The corrosion resistance was evaluated by various methods including open circuit potential (OCP), linear polarization resistance (LPR) measurements, and electrochemical impedance spectroscopy (EIS). Meanwhile, the 2205 duplex stainless steel (SS steel) was evaluated for comparison. Moreover, the passive film with CR steel was studied by means of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Atomic Force Microscope (AFM), and the Mott‑Schottky approach. The results showed that the excellent passivity of CR steel could be detected in a high alkaline environment. The grain boundaries between the fine passive film particles lead to increasing Cr oxide content in the later passivation stage. The filling of cation vacancies in the later passivation stage as well as the orderly crystalized inner layer contributed to the excellent corrosion resistance of CR steel. A passive film growth model for CR steel was proposed.

Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li 2BeF 4(FLiBe) salt

DOE PAGES

Zheng, Guiqiu; He, Lingfeng; Carpenter, David; ...

2016-10-12

The microstructural evaluation and characterization of 316 stainless steel samples that were tested in molten Li 2BeF 4 (FLiBe) salt were investigated in this study for evaluating its performance in high-temperature molten fluoride salts. Recently, 316 stainless steel and FLiBe salt are being actively considered as the main structural alloy and primary coolant of fluoride salt-cooled high-temperature reactor (FHR), a leading nuclear reactor concept for the next generation nuclear plants (NGNP). In support of the materials development for the FHR, high-temperature corrosion tests of 316 stainless steel in molten FLiBe salt at 700°C have been conducted in both bare graphitemore » crucibles and 316 stainless steel-lined crucibles in an inert atmosphere for up to 3000 hours. The microstructure of the tested samples was comprehensively characterized using scanning electron microscopy (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM) with EDS. In addition to the noticeable intergranular corrosion attack on surface, the corrosion in terms of the Cr depletion along high angle grain boundaries (15-180º) extended to 22µm in depth after 3000-hour exposure to molten FLiBe salt in graphite crucible. The coherent Σ3 grain boundary appeared high resistance to the Cr depletion. The substantial Cr depletion from the near-to-surface layer induced phase transformation from γ-martensite to α-ferrite phase (FeNi x) during corrosion at 700ºC. Furthermore, the presence of graphite in the molten salt doubled the corrosion attack depth and led to the formation of round Mo2C, hexagonal Cr 7C 3 and needle-like Al 4C 3 phase within the alloy as deep as 50 µm after 3000-hour corrosion testing. Based on the microstructural analysis, the corrosion mechanisms of 316 stainless steel in molten FLiBe salt in different corrosion crucibles were illuminated through schematic

Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li 2BeF 4(FLiBe) salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Guiqiu; He, Lingfeng; Carpenter, David

The microstructural evaluation and characterization of 316 stainless steel samples that were tested in molten Li 2BeF 4 (FLiBe) salt were investigated in this study for evaluating its performance in high-temperature molten fluoride salts. Recently, 316 stainless steel and FLiBe salt are being actively considered as the main structural alloy and primary coolant of fluoride salt-cooled high-temperature reactor (FHR), a leading nuclear reactor concept for the next generation nuclear plants (NGNP). In support of the materials development for the FHR, high-temperature corrosion tests of 316 stainless steel in molten FLiBe salt at 700°C have been conducted in both bare graphitemore » crucibles and 316 stainless steel-lined crucibles in an inert atmosphere for up to 3000 hours. The microstructure of the tested samples was comprehensively characterized using scanning electron microscopy (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM) with EDS. In addition to the noticeable intergranular corrosion attack on surface, the corrosion in terms of the Cr depletion along high angle grain boundaries (15-180º) extended to 22µm in depth after 3000-hour exposure to molten FLiBe salt in graphite crucible. The coherent Σ3 grain boundary appeared high resistance to the Cr depletion. The substantial Cr depletion from the near-to-surface layer induced phase transformation from γ-martensite to α-ferrite phase (FeNi x) during corrosion at 700ºC. Furthermore, the presence of graphite in the molten salt doubled the corrosion attack depth and led to the formation of round Mo2C, hexagonal Cr 7C 3 and needle-like Al 4C 3 phase within the alloy as deep as 50 µm after 3000-hour corrosion testing. Based on the microstructural analysis, the corrosion mechanisms of 316 stainless steel in molten FLiBe salt in different corrosion crucibles were illuminated through schematic

Effects of chitosan inhibitor on the electrochemical corrosion behavior of 2205 duplex stainless steel

NASA Astrophysics Data System (ADS)

Yang, Se-fei; Wen, Ying; Yi, Pan; Xiao, Kui; Dong, Chao-fang

2017-11-01

The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency (IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl3 solution.

Fe-Based Amorphous Coatings on AISI 4130 Structural Steel for Corrosion Resistance

NASA Astrophysics Data System (ADS)

Katakam, Shravana; Santhanakrishnan, S.; Dahotre, Narendra B.

2012-06-01

The current study focuses on synthesizing a novel functional coating for corrosion resistance applications, via laser surface alloying. The iron-based (Fe48Cr15Mo14Y2C15B) amorphous precursor powder is used for laser surface alloying on AISI 4130 steel substrate, with a continuous wave ytterbium Nd-YAG fiber laser. The corrosion resistance of the coatings is evaluated for different processing conditions. The microstructural evolution and the response of the microstructure to the corrosive environment is studied using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Microstructural studies indicate the presence of face-centered cubic Fe-based dendrites intermixed within an amorphous matrix along with fine crystalline precipitates. The corrosion resistance of the coatings decrease with an increase in laser energy density, which is attributed to the precipitation and growth of chromium carbide. The enhanced corrosion resistance of the coatings processed with low energy density is attributed to the self-healing mechanism of this amorphous system.

Stress corrosion cracking properties of 15-5PH steel

NASA Technical Reports Server (NTRS)

Rosa, Ferdinand

1993-01-01

Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

Synergistic effect of tartaric acid with 2,6-diaminopyridine on the corrosion inhibition of mild steel in 0.5 M HCl

PubMed Central

Qiang, Yujie; Guo, Lei; Zhang, Shengtao; Li, Wenpo; Yu, Shanshan; Tan, Jianhong

2016-01-01

The inhibitive ability of 2,6-diaminopyridine, tartaric acid and their synergistic effect towards mild steel corrosion in 0.5 M HCl solution was evaluated at various concentrations using potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS), and weight loss experiments. Corresponding surfaces of mild steel were examined by atomic force microscope (AFM), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) analysis. The experimental results are in good agreement and reveal a favorable synergistic effect of 2,6-diaminopyridine with tartaric acid, which could protect mild steel from corrosion effectively. Besides, quantum chemical calculations and Monte Carlo simulation were used to clarify the inhibition mechanism of the synergistic effect. PMID:27628901

Stainless steel corrosion scale formed in reclaimed water: Characteristics, model for scale growth and metal element release.

PubMed

Cui, Yong; Liu, Shuming; Smith, Kate; Hu, Hongying; Tang, Fusheng; Li, Yuhong; Yu, Kanghua

2016-10-01

Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl - and SO 4 2- ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales. Copyright © 2016. Published by Elsevier B.V.

Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oilfield produced water under sweet conditions: Combined experimental and computational investigations

NASA Astrophysics Data System (ADS)

Migahed, M. A.; elgendy, Amr.; EL-Rabiei, M. M.; Nady, H.; Zaki, E. G.

2018-05-01

Two new sequences of Gemini di-quaternary ammonium salts were synthesized characterized by FTIR and 1HNMR spectroscopic techniques and evaluated as corrosion inhibitor for X-65 steel dissolution in deep oil wells formation water saturated with CO2. The anti-corrosion performance of these compounds was studied by different electrochemical techniques i.e. (potentiodynamic polarization and AC impedance methods), Surface morphology (SEM and EDX) analysis and quantum chemical calculations. Results showed that the synthesized compounds were of mixed-type inhibitors and the inhibition capability was influenced by the inhibitor dose and the spacer substitution in their structure as indicated by Tafel plots. Surface active parameters were determined from the surface tension profile. The synthesized compounds adsorbed via Langmuir adsorption model with physiochemical adsorption as inferred from the standard free energy (ΔG°ads) values. Surface morphology (SEM and EDX) data for inhibitor (II) shows the development of adsorbed film on steel specimen. Finally, the experimental results were supported by the quantum chemical calculations using DFT theory.

In vitro corrosion resistance of plasma source ion nitrided austenitic stainless steels.

PubMed

Le, M K; Zhu, X M

2001-04-01

Plasma source ion nitriding has emerged as a low-temperature, low-pressure nitriding approach for low-energy implanting nitrogen ions and then diffusing them into steel and alloy. In this work, a single high nitrogen face-centered-cubic (f.c.c.) phase (gammaN) formed on the 1Cr18Ni9Ti and AISI 316L austenitic stainless steels with a high nitrogen concentration of about 32 at % was characterized using Auger electron spectroscopy, electron probe microanalysis, glancing angle X-ray diffraction, and transmission electron microscopy. The corrosion resistance of the gammaN-phase layer was studied by the electrochemical cyclic polarization measurement in Ringer's solutions buffered to pH from 3.5 to 7.2 at a temperature of 37 degrees C. No pitting corrosion in the Ringer's solutions with pH = 7.2 and 5.5 was detected for the gammaN-phase layers on the two stainless steels. The high pitting potential for the gammaN-phase layers is higher, about 500 and 600 mV, above that of the two original stainless steels, respectively, in the Ringer's solution with pH = 3.5. The corroded surface morphologies of the gammaN-phase layers observed by scanning electron microscopy are consistent with the results of the electrochemical polarization measurement.

Development of new corrosion inhibitor tested on mild steel supported by electrochemical study

NASA Astrophysics Data System (ADS)

Habeeb, Hussein Jwad; Luaibi, Hasan Mohammed; Dakhil, Rifaat Mohammed; Kadhum, Abdul Amir H.; Al-Amiery, Ahmed A.; Gaaz, Tayser Sumer

2018-03-01

Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol have been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution (HCl) using electrochemical measurements test includes PD (Potentiodynamic), EIS (Electrochemical impedance spectroscopy), OCP (Open circuit potential) and EFM (electrochemical frequency modulation). The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol corrosion inhibitors are effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases.

Effect of Different Cooling Rates on the Corrosion Behavior of High-Carbon Pearlitic Steel

NASA Astrophysics Data System (ADS)

Katiyar, Prvan Kumar; Misra, Sudhir; Mondal, K.

2018-03-01

The present work discusses the effect of pearlitic morphology on the corrosion behavior of high-carbon fully pearlitic steel in 3.5% NaCl solution. Four different types of pearlitic steels (furnace-cooled, as-received, air-cooled and forced-air-cooled) consisting of coarse, medium, fine and very fine microstructures, respectively, were tested. Electrochemical behavior of these steels was studied with the help of dynamic and linear polarization and AC impedance spectroscopic tests. The corrosion resistance improved with fineness of the microstructure in general. However, with further reduction in interlamellar spacing beyond a limit, the corrosion resistance reduced slightly. Formation of homogeneous distribution of microgalvanic cells between cementite and ferrite lamellae of fine pearlitic steel improved the corrosion resistance. However, entanglement of the lamellae of pearlite in very fine pearlitic structure as well as breaking of cementite lamellae due to finer pearlitic colonies was attributed to the higher corrosion of the forced-air-cooled steel as compared to the air-cooled steel.

Corrosion Behavior of Steels in Supercritical CO 2 for Power Cycle Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Repukaiti, Richard; Teeter, Lucas; Ziomek-Moroz, Margaret

In order to understand issues with corrosion of heat exchanger materials in direct supercritical carbon dioxide (sCO 2) power cycles, a series of autoclave exposure experiments and electrochemical experiments have been conducted. Corrosion behaviors of 347H stainless steel and P91 martensitic-ferrtic steel in sCO 2 environment have been compared. In autoclave exposure tests performed at 50°C- 245°C and 80 bar. Mass change measurements, surface characterization, and corrosion product analysis have been conducted to understand the corrosion behavior of steels in sCO 2 containing H 2O and O 2. Electrochemical tests performed at room temperature and 50°C, a simulation environment ofmore » water condensation phase with dissolved CO 2 was prepared to evaluate the corrosion resistance of materials. From both types of experiments, generally 347H showed higher corrosion resistance than P91.« less

Ginger extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

NASA Astrophysics Data System (ADS)

Fidrusli, A.; Suryanto; Mahmood, M.

2018-01-01

Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extract to form green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid. The experiment of weight loss method and polarization technique were conducted to measure corrosion rate and inhibition efficiency of mild steel in solution containing 1.0 M of hydrochloric acid with various concentration of inhibitor at room temperature. The results showed that, the rate of corrosion dropped from 8.09 mmpy in solution containing no inhibitor to 0.72 mmpy in solution containing 150g/l inhibitor while inhibition efficiency up to 91% was obtained. The polarization curve in polarization experiments shows that the inhibition efficiency is 86% with high concentration of inhibitor. The adsorption of ginger extract on the surface of mild steel was observed by using optical microscope and the characterization analysis was done by using pH measurement method. When high concentration of green inhibitor in the acid solution is used, the pH at the surface of steel is increasing.

Image-based corrosion recognition for ship steel structures

NASA Astrophysics Data System (ADS)

Ma, Yucong; Yang, Yang; Yao, Yuan; Li, Shengyuan; Zhao, Xuefeng

2018-03-01

Ship structures are subjected to corrosion inevitably in service. Existed image-based methods are influenced by the noises in images because they recognize corrosion by extracting features. In this paper, a novel method of image-based corrosion recognition for ship steel structures is proposed. The method utilizes convolutional neural networks (CNN) and will not be affected by noises in images. A CNN used to recognize corrosion was designed through fine-turning an existing CNN architecture and trained by datasets built using lots of images. Combining the trained CNN classifier with a sliding window technique, the corrosion zone in an image can be recognized.

Corrosion detection in steel-reinforced concrete using a spectroscopic technique

NASA Astrophysics Data System (ADS)

Garboczi, E. J.; Stutzman, P. E.; Wang, S.; Martys, N. S.; Hassan, A. M.; Duthinh, D.; Provenzano, V.; Chou, S. G.; Plusquellic, D. F.; Surek, J. T.; Kim, S.; McMichael, R. D.; Stiles, M. D.

2014-02-01

Detecting the early corrosion of steel that is embedded in reinforced concrete (rebar) is a goal that would greatly facilitate the inspection and measurement of corrosion in the US physical infrastructure. Since 2010, the National Institute of Standards and Technology (NIST) has been working on a large project to develop an electromagnetic (EM) probe that detects the specific corrosion products via spectroscopic means. Several principal iron corrosion products, such as hematite and goethite, are antiferromagnetic at field temperatures. At a given applied EM frequency, which depends on temperature, these compounds undergo a unique absorption resonance that identifies the presence of these particular iron corrosion products. The frequency of the resonances tends to be on the order of 100 GHz or higher, so transmitting EM waves through the cover concrete and back out again at a detectable level has been challenging. NIST has successfully detected these two iron corrosion products, and is developing equipment and methodologies that will be capable of penetrating the typical 50 mm of cover concrete in the field. The novel part of this project is the detection of specific compounds, rather than only geometrical changes in rebar cross-section. This method has the potential of providing an early-corrosion probe for steel in reinforced concrete, and for other applications where steel is covered by various layers and coatings.

In-situ Raman and X-ray photoelectron spectroscopic studies on the pitting corrosion of modified 9Cr-1Mo steel in neutral chloride solution

NASA Astrophysics Data System (ADS)

Ramya, S.; Nanda Gopala Krishna, D.; Mudali, U. Kamachi

2018-01-01

In-situ Raman and X-ray photoelectron spectroscopic studies were performed for the identification of native and corroded surface oxide layers of modified 9Cr-1Mo steel. The Raman data obtained for native oxide layer of modified 9Cr-1Mo steel revealed that it was mainly composed of oxides of Fe and Cr. The presence of alloying element Mo was found to be less significant in the native oxide film. The oxides of Cr were dominant at the surface and were found to be decreasing closer to metal/oxide layer interface. The changes in the chemical composition of the native films upon in-situ pitting during potentiostatic polarization experiment were characterized by in-situ Raman analysis. The corrosion products of potentiostatically polarized modified 9Cr-1Mo steel was composed of dominant Fe (III) phases viz., γ- Fe2O3, α and γ - FeOOH along with the oxides of chromium. The results from Raman analysis were corroborated with the XPS experiments on as received and pitted samples of modified 9Cr-1Mo steel specimens. It was observed that the oxides of Cr and Mo contributed for the stability of the surface layer by forming Cr2O3 and MoO3. Also, the study attempted to find out the intermediate corrosion products inside the metastable pits to account for the pseudo passive behavior of modified 9Cr-1Mo steel in 0.1 M NaCl solution.

Corrosion monitoring on a large steel pressure vessel by thin-layer activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, G.; Boulton, L.H.; Hodder, D.

1989-12-01

Thin-layer activation (TLA) is a technique in which a surface is irradiated by a nuclear accelerator and thereby labeled with an accurate depth profile of low-level radioactivity. By monitoring this activity it is possible to calculate how much of that surface has been removed by corrosion. As the radioactivity is marked by the emission of penetrating gamma rays, it is possible to monitor this corrosion remotely through several centimeters of steel. This technique has been used to monitor erosion-corrosion occurring on the inner carbon steel wall of a continuous Kraft pulp digester at a paper mill. Representative coupons of themore » same steel as the digester wall were irradiated and fixed to the walls in the liquor extraction zone during a maintenance shutdown. The loss of metal over the six months was measured by external monitoring of gamma radiation through the vessel wall, and converted to a corrosion rate. Subsequent weight-loss measurements and comparison with ultrasonic thickness measurements established that the corrosion rate measured gave accurate results over a much shorter time scale. TLA thus enables current, rather than historical corrosion rates to be measured in a large steel pressure vessel.« less

Sliding Wear Characteristics and Corrosion Behaviour of Selective Laser Melted 316L Stainless Steel

NASA Astrophysics Data System (ADS)

Sun, Y.; Moroz, A.; Alrbaey, K.

2014-02-01

Stainless steel is one of the most popular materials used for selective laser melting (SLM) processing to produce nearly fully dense components from 3D CAD models. The tribological and corrosion properties of stainless steel components are important in many engineering applications. In this work, the wear behaviour of SLM 316L stainless steel was investigated under dry sliding conditions, and the corrosion properties were measured electrochemically in a chloride containing solution. The results show that as compared to the standard bulk 316L steel, the SLM 316L steel exhibits deteriorated dry sliding wear resistance. The wear rate of SLM steel is dependent on the vol.% porosity in the steel and by obtaining full density it is possible achieve wear resistance similar to that of the standard bulk 316L steel. In the tested chloride containing solution, the general corrosion behaviour of the SLM steel is similar to that of the standard bulk 316L steel, but the SLM steel suffers from a reduced breakdown potential and is more susceptible to pitting corrosion. Efforts have been made to correlate the obtained results with porosity in the SLM steel.

Localized CO2 corrosion of carbon steel with different microstructures in brine solutions with an imidazoline-based inhibitor

NASA Astrophysics Data System (ADS)

Zhang, Huan-huan; Pang, Xiaolu; Gao, Kewei

2018-06-01

CO2 corrosion behavior of carbon steel with different microstructures (H steel: coarse laminar pearlite; T steel: globular and shot rod shaped pearlite) was analyzed in 3 wt.% NaCl solution at 60 °C with imidazoline-based inhibitor by electrochemical and weight loss methods. Electrochemical measurements showed that, compared to H steel, the inhibitor film adsorbed on T steel had a higher pitting corrosion resistance and the inhibition efficiency for T steel was larger at each concentration of inhibitor. Weight loss results exhibited that both steels suffered general corrosion in absence of inhibitor; however, localized corrosion was observed on the samples with insufficient concentration of inhibitor. H steel suffered more severe localized corrosion than T steel, it was related to that H steel had a higher density of dislocations in the pearlite area and the larger driving force for galvanic corrosion. The localized corrosion on H steel mainly distributed on the laminar pearlite area.

Electrochemical study on the corrosion resistance of plasma nanocoated 316L stainless steel in albumin- and lysozyme-containing electrolytes

PubMed Central

Jones, John Eric; Chen, Meng; Chou, Ju; Yu, Qingsong

2017-01-01

The physiological corrosion resistance of plasma nanocoated 316L stainless steel was studied in protein-containing electrolytes using electrochemical methods. Plasma nanocoatings with thicknesses of 20–30 nm were deposited onto 316L stainless steel coupons in a glow discharge of trimethylsilane (TMS) or its mixture with oxygen gas under various gas ratios. The surface chemistries of the plasma nanocoatings were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Corrosion properties of the plasma nanocoated 316L stainless steel coupons were assessed using potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) in phosphate-buffered saline (PBS) electrolytes that contain bovine serum albumin (BSA) or lysozyme. It was found that BSA adsorption on the plasma nanocoated 316L coupons was heavily favored. BSA adsorption on the plasma nanocoating surfaces could block charge-transfer reactions between the electrolyte and 316L substrate, and thus stabilize the 316L substrates from further corrosion. In contrast, lysozyme adsorption on the plasma nanocoated specimens was not as pronounced and mildly influenced the corrosion properties of the plasma nanocoated 316L stainless steel. PMID:29422723

Estimation of corrosion damage in steel reinforced mortar using waveguides

NASA Astrophysics Data System (ADS)

Reis, Henrique; Ervin, Benjamin L.; Kuchma, Daniel A.; Bernhard, Jennifer

2005-05-01

Corrosion of reinforced concrete is a chronic infrastructure problem, particularly in areas with deicing salt and marine exposure. To maintain structural integrity, a testing method is needed to identify areas of corroding reinforcement. For purposes of rehabilitation, the method must also be able to evaluate the degree, rate and location of damage. Towards the development of a wireless embedded sensor system to monitor and assess corrosion damage in reinforced concrete, reinforced mortar specimens were manufactured with seeded defects to simulate corrosion damage. Taking advantage of waveguide effects of the reinforcing bars, these specimens were then tested using an ultrasonic approach. Using the same ultrasonic approach, specimens without seeded defects were also monitored during accelerated corrosion tests. Both the ultrasonic sending and the receiving transducers were mounted on the steel rebar. Advantage was taken of the lower frequency (<250 kHz) fundamental flexural propagation mode because of its relatively large displacements at the interface between the reinforcing steel and the surrounding concrete. Waveform energy (indicative of attenuation) is presented and discussed in terms of corrosion damage. Current results indicate that the loss of bond strength between the reinforcing steel and the surrounding concrete can be detected and evaluated.

Corrosion of stainless steels in lead-bismuth eutectic up to 600 °C

NASA Astrophysics Data System (ADS)

Soler, L.; Martín, F. J.; Hernández, F.; Gómez-Briceño, D.

2004-11-01

An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 °C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 °C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures.

Metallurgical effects on chloride ion corrosion threshold of steel in concrete.

DOT National Transportation Integrated Search

2001-11-30

The chloride-induced corrosion of reinforcing steel bars (rebar) in concrete seriously limits durability of reinforcing concrete structures. This investigation examines key issues in pitting corrosion and chloride corrosion threshold of rebar in alka...

Influence of hydrogen on the corrosion behavior of stainless steels in lithium

NASA Astrophysics Data System (ADS)

Shulga, A. V.

2008-02-01

Corrosion behavior of several stainless steels in lithium and lithium with 0.05%H has been examined. Corrosion tests were performed under static conditions at 600 and 700 °C in the austenitic stainless steel of the type AISI 304 containers. Intensive formation of σ-phase of the composition Fe 50Cr 43Mo 3Ni 4 on the surface of austenitic stainless steels of the type AISI 316 at 700 °C for 1000 h was established as a result of isothermal mass transfer. Addition of 0.05%H in the form of LiH to lithium resulted in an increase in the quantity of the σ-phase. After corrosion tests of ferritic/martensitic steel in lithium at 700 °C for 1000 h the formation of the γ-phase was observed. In Li + 0.05%H besides the γ-phase was also formed the σ-phase. The features of decarburization of investigated stainless steels were examined using the direct method of activation autoradiography on carbon. Addition of 0.05%H in lithium significantly decreased the carbon content in the decarburization zone of austenitic stainless steel Fe-18Cr-15Ni-0.15C-0.23B without a noticeable change in the thickness of the decarburization zone. Decarburization of ferritic/martensitic stainless steel was less than of austenitic stainless steel using the same corrosion tests.

Effect of pH on Semiconducting Property of Passive Film Formed on Ultra-High-Strength Corrosion-Resistant Steel in Sulfuric Acid Solution

NASA Astrophysics Data System (ADS)

Sun, Min; Xiao, Kui; Dong, Chaofang; Li, Xiaogang; Zhong, Ping

2013-10-01

Because Cr9Ni5MoCo14 is a new ultra-high-strength corrosion-resistant steel, it is important to study its corrosion behavior in sulfuric acid solution, which is used to simulate the aggressive environment. The effect of pH on the electrochemical and semiconducting properties of passive films formed on ultra-high-strength corrosion-resistant steel in sulfuric acid solution was investigated by means of the potentiodynamic polarization technique, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and X-ray photoelectron spectroscopy (XPS). The results indicated that Cr9Ni5MoCo14 steel showed a passive state in acid solutions. The corrosion behavior of this Cr9Ni5MoCo14 alloy was influenced by the passive film formed on the surface, including thickness, stability, and partitioning of elements of the passive film. The passive current density decreases with increasing pH, and the corrosion resistance was enhanced by the increasing thickness and depletion of the defects within the passive film. Moreover, an enrichment of chromium (primarily the oxides of Cr) and depletion of iron in the passive film led to improved corrosion resistance. These results can provide a theoretical basis for use of this alloy and further development of ultra-high-strength corrosion-resistant steel in today's society.

Nano-micro structured superhydrophobic zinc coating on steel for prevention of corrosion and ice adhesion.

PubMed

Brassard, J D; Sarkar, D K; Perron, J; Audibert-Hayet, A; Melot, D

2015-06-01

Thin films of zinc have been deposited on steel substrates by electrodeposition process and further functionalized with ultra-thin films of commercial silicone rubber, in order to obtain superhydrophobic properties. Morphological feature, by scanning electron microscope (SEM), shows that the electrodeposited zinc films are composed of micro-nano rough patterns. Furthermore, chemical compositions of these films have been analyzed by X-ray diffraction (XRD) and infra-red (IRRAS). An optimum electrodeposition condition, based on electrical potential and deposition time, has been obtained which provides superhydrophobic properties with a water contact angle of 155±1°. The corrosion resistance properties, in artificial seawater, of the superhydrophobic zinc coated steel are found to be superior to bare steel. Similarly, the measured ice adhesion strength on superhydrophobic surfaces, using the centrifugal adhesion test (CAT), is found to be 6.3 times lower as compared to bare steel. This coating has promising applications in offshore environment, to mitigate corrosion and reduce ice adhesion. Copyright © 2014 Elsevier Inc. All rights reserved.

Investigation of high temperature corrosion behavior on 304L austenite stainless steel in corrosive environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahri, M. I.; Othman, N. K.; Samsu, Z.

2014-09-03

In this work, 304L stainless steel samples were exposed at 700 °C for 10hrs in different corrosive environments; dry oxygen, molten salt, and molten salt + dry oxygen. The corrosion behavior of samples was analyzed using weight change measurement technique, optical microscope (OM) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX). The existence phases of corroded sample were determined using X-ray Diffraction (XRD). The lowest corrosion rate was recorded in dry oxygen while the highest was in molten salt + dry oxygen environments with the value of 0.0062 mg/cm{sup 2} and −13.5225 mg/cm{sup 2} respectively. The surfacemore » morphology of sample in presence of salt mixture showed scale spallation. Oxide scales of Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3} were the main phases developed and detected by XRD technique. Cr{sub 2}O{sub 3} was not developed in every sample as protective layers but chromate-rich oxide was developed. The cross-section analysis found the oxide scales were in porous, thick and non-adherent that would not an effective barrier to prevent from further degradation of alloy. EDX analysis also showed the Cr-element was low compared to Fe-element at the oxide scale region.« less

Corrosion and stress corrosion cracking of ferritic/martensitic steel in super critical pressurized water

NASA Astrophysics Data System (ADS)

Hirose, T.; Shiba, K.; Enoeda, M.; Akiba, M.

2007-08-01

A water-cooled solid breeder (WCSB) blanket cooled by high temperature SCPW (super critical pressurized water) is a practical option of DEMO reactor. Therefore, it is necessary to check the compatibility of the steel with SCPW. In this work, reduced activation ferritic/martensitic steel, F82H has been tested through slow strain rate tests (SSRT) in 23.5 MPa SCPW. And weight change behavior was measured up to 1000 h. F82H did not demonstrated stress corrosion cracking and its weight simply increased with surface oxidation. The weight change of F82H was almost same as commercial 9%-Cr steels. According to a cross-sectional analysis and weight change behavior, corrosion rate of F82H in the 823 K SCPW is estimated to be 0.04 mm/yr.

Microbial fouling and corrosion of carbon steel in deep anoxic alkaline groundwater.

PubMed

Rajala, Pauliina; Bomberg, Malin; Vepsäläinen, Mikko; Carpén, Leena

2017-02-01

Understanding the corrosion of carbon steel materials of low and intermediate level radioactive waste under repository conditions is crucial to ensure the safe storage of radioactive contaminated materials. The waste will be in contact with the concrete of repository silos and storage containers, and eventually with groundwater. In this study, the corrosion of carbon steel under repository conditions as well as the microbial community forming biofilm on the carbon steel samples, consisting of bacteria, archaea, and fungi, was studied over a period of three years in a groundwater environment with and without inserted concrete. The number of biofilm forming bacteria and archaea was 1,000-fold lower, with corrosion rates 620-times lower in the presence of concrete compared to the natural groundwater environment. However, localized corrosion was detected in the concrete-groundwater environment indicating the presence of local microenvironments where the conditions for pitting corrosion were favorable.

Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Nelson, E. E.

1980-01-01

The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

Accelerated corrosion of 2205 duplex stainless steel caused by marine aerobic Pseudomonas aeruginosa biofilm.

PubMed

Xu, Dake; Xia, Jin; Zhou, Enze; Zhang, Dawei; Li, Huabing; Yang, Chunguang; Li, Qi; Lin, Hai; Li, Xiaogang; Yang, Ke

2017-02-01

Microbiologically influenced corrosion (MIC) of 2205 duplex stainless steel (DSS) in the presence of Pseudomonas aeruginosa was investigated through electrochemical and surface analyses. The electrochemical results showed that P. aeruginosa significantly reduced the corrosion resistance of 2205 DSS. Confocal laser scanning microscopy (CLSM) images showed that the depths of the largest pits on 2205 DSS with and without P. aeruginosa were 14.0 and 4.9μm, respectively, indicating that the pitting corrosion was accelerated by P. aeruginosa. X-ray photoelectron spectroscopy (XPS) results revealed that CrO 3 and CrN formed on the 2205 DSS surface in the presence of P. aeruginosa. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental investigation of microbiologically influenced corrosion of selected steels in sugarcane juice environment.

PubMed

Wesley, Sunil Bala; Maurya, Devendra Prasad; Goyal, Hari Sharan; Negi, Sangeeta

2013-12-01

In the current study, ferritic stainless grades AISI 439 and AISI 444 were investigated as possible construction materials for machinery and equipment in the cane-sugar industry. Their performance in corrosive cane-sugar juice environment was compared with the presently used low carbon steel AISI 1010 and austenitic stainless steel AISI 304. The Tafel plot electrochemical technique was used to evaluate general corrosion performance. Microbiologically influenced corrosion (MIC) behaviour in sugarcane juice environment was studied. Four microbial colonies were isolated from the biofilms on the metal coupon surfaces on the basis of their different morphology. These were characterized as Brevibacillus parabrevis, Bacillus azotoformans, Paenibacillus lautus and Micrococcus sp. The results of SEM micrographs showed that AISI 439 and AISI 304 grades had suffered maximum localized corrosion. MIC investigations revealed that AISI 444 steel had the best corrosion resistance among the tested materials. However from the Tafel plots it was evident that AISI 1010 had the least corrosion resistance and AISI 439 the best corrosion resistance.

Corrosion-Fatigue Cracking in HY-80 and HY-130 Steels

DTIC Science & Technology

2015-01-22

Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6355--15-9584 Corrosion- Fatigue Cracking in HY-80 and HY-130 Steels January 22, 2015 P.S...RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (include area code) b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Corrosion- Fatigue ...including [NaCl] concentration) and load ratio on fatigue crack growth kinetics of HY-80 and HY-130 steels. Fracture mechanics wedge-opening-load

Application Electrochemical Impedance Spectroscopy Methods to Evaluation Corrosion Behavior of Stainless steels 304 in Nanofluids Media

NASA Astrophysics Data System (ADS)

Hadi Prajitno, Djoko; Umar, Efrizon; Gustaman Syarif, Dani

2017-01-01

Corrosion is a common problem in many engineering metals and alloys. Electrochemical methods are commonly instrument to use as tool to study the corrosion behavior of the metals and alloy. This method was examined interaction between a surface of the metals and alloys in corrosive media. The present paper, the effects of nano particle ZrO2 as an additive to aqua de mineralized on the corrosion behavior of stainless steel were investigated. Electrochemical impedance spectroscopy (EIS) testing was performed in both de mineralized water and demineralized water contain nano particle 0,01% ZrO2 as Nano fluid. Surface morphology examination of the specimens showed that microstructure of stainless steel 304 alloys relatively unchanged after corrosion and EIS testing. According to the corrosion potential examination of the stainless steel 304 in nanofluid media, it showed that stainless steel 304 actively corroded in nanofluida media. The value of anodic Tafel slope stainless steel 304 in nanofluid higher compare with in demineralized water. Tafel polarization examination show that corrosion rate of stainless steel 304 in nanofluid higher compare with corrosin rate in demineralized media.EIS technique show that impedance of stainless steel 304 in nanofluid lower compare with in demineralized media, resulting in an increase in the corrosion rates of these stainless steel 304 specimens in nano fluids

Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

PubMed Central

Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

2014-01-01

Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion. PMID:24558346

Monitoring corrosion of steel bars in reinforced concrete structures.

PubMed

Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

2014-01-01

Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion.

Erosion-corrosion resistance properties of 316L austenitic stainless steels after low-temperature liquid nitriding

NASA Astrophysics Data System (ADS)

Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Pan, Dong

2018-05-01

The low-temperature liquid nitriding of stainless steels can result in the formation of a surface zone of so-called expanded austenite (S-phase) by the dissolution of large amounts of nitrogen in the solid solution and formation of a precipitate-free layer supersaturated with high hardness. Erosion-corrosion measurements were performed on low-temperature nitrided and non-nitrided 316L stainless steels. The total erosion-corrosion, erosion-only, and corrosion-only wastages were measured directly. As expected, it was shown that low-temperature nitriding dramatically reduces the degree of erosion-corrosion in stainless steels, caused by the impingement of particles in a corrosive medium. The nitrided 316L stainless steels exhibited an improvement of almost 84% in the erosion-corrosion resistance compared to their non-nitrided counterparts. The erosion-only rates and synergistic levels showed a general decline after low-temperature nitriding. Low-temperature liquid nitriding can not only reduce the weight loss due to erosion but also significantly reduce the weight loss rate of interactions, so that the total loss of material decreased evidently. Therefore, 316L stainless steels displayed excellent erosion-corrosion behaviors as a consequence of their highly favorable corrosion resistances and superior wear properties.

77 FR 24221 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-23

...)] Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission Determinations... countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead...

Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062

NASA Astrophysics Data System (ADS)

Rosemann, P.; Müller, C.; Baumann, O.; Modersohn, W.; Halle, T.

2017-03-01

The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.

Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel

NASA Astrophysics Data System (ADS)

Panigrahi, B. K.; Srikanth, S.; Sahoo, G.

2009-11-01

The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

Tribological and corrosion properties of plasma nitrided and nitrocarburized 42CrMo4 steel

NASA Astrophysics Data System (ADS)

Kusmic, D.; Van Thanh, D.

2017-02-01

This article deals with tribological and corrosion resistance comparison of plasma nitrided and nitrocarburized 42CrMo4 steel used for breech mechanism in the armament production. Increasing of materials demands (like wear resistance, surface hardness, running-in properties and corrosion resistance) used for armament production and in other industrial application leads in the field of surface treatment. Experimental steel samples were plasma nitrided under different nitriding gas ratio at 500 °C for 15h and nitrocarburized for 45 min at temperature 590°C and consequently post-oxidized for 10 min at 430°C. Individual 42CrMo4 steel samples were subsequently metallographically evaluated and characterized by hardness and microhardness measuring. The wear test “ball on disc” was realized for measuring of adhesive wear and coefficient of friction during unlubricated sliding. NSS corrosion tests were realized for corrosion resistance evaluation and expressed by corroded area and calculated corrosion rate. The corrosion resistance evaluation is by the surface corrosion-free surfaces evaluation supplemented using the laser confocal microscopy. Due to different surface treatment and plasma nitriding conditions, there are wear resistance and corrosion resistance differences evident between the plasma nitrided steel samples as well.

Microstructure, corrosion and tribological and antibacterial properties of Ti-Cu coated stainless steel.

PubMed

Jin, Xiaomin; Gao, Lizhen; Liu, Erqiang; Yu, Feifei; Shu, Xuefeng; Wang, Hefeng

2015-10-01

A Ti-Cu coated layer on 316L stainless steel (SS) was obtained by using the Closed Field Unbalanced Magnetron Sputtering (CFUBMS) system to improve antibacterial activity, corrosion and tribological properties. The microstructure and phase constituents of Ti-Cu coated layer were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectrometry (GDOES). The corrosion and tribological properties of a stainless steel substrate, SS316L, when coated with Ti-Cu were investigated in a simulated body fluid (SBF) environment. The viability of bacteria attached to the antibacterial surface was tested using the spread plate method. The results indicate that the Ti-Cu coated SS316L could achieve a higher corrosion polarization resistance and a more stable corrosion potential in an SBF environment than the uncoated SS316L substrate. The desirable corrosion protection performance of Ti-Cu may be attributable to the formation of a Ti-O passive layer on the coating surface, protecting the coating from further corrosion. The Ti-Cu coated SS316L also exhibited excellent wear resistance and chemical stability during the sliding tests against Si3N4 balls in SBF environment. Moreover, the Ti-Cu coatings exhibited excellent antibacterial abilities, where an effective reduction of 99.9% of Escherichia coli (E.coli) within 12h was achieved by contact with the modified surface, which was attributed to the release of copper ions when the Ti-Cu coatings are in contact with bacterial solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wear and corrosion resistance of laser-cladded Fe-based composite coatings on AISI 4130 steel

NASA Astrophysics Data System (ADS)

Fan, Li; Chen, Hai-yan; Dong, Yao-hua; Dong, Li-hua; Yin, Yan-sheng

2018-06-01

The wear and corrosion resistance of Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 and Fe77.3Cr15.8Ni3.9Mo1.1Mn0.5C0.2Si1.2 coatings laser-cladded on AISI 4130 steel were studied. The coatings possess excellent wear and corrosion resistance despite the absence of expensive yttrium, tungsten, and cobalt and very little molybdenum. The microstructure mainly consists of dendrites and eutectic phases, such as duplex (γ+α)-Fe and the Fe-Cr (Ni) solid solution, confirmed via energy dispersive spectrometry and X-ray diffraction. The cladded Fe-based coatings have lower coefficients of friction, and narrower and shallower wear tracks than the substrate without the cladding, and the main wear mechanism is mild abrasive wear. Electrochemical test results suggest that the soft Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 coating with high Cr and Ni concentrations has high passivation resistance, low corrosion current, and positive corrosion potential, providing a better protective barrier layer to the AISI 4130 steel against corrosion.

Stress Corrosion Behavior of 12Cr Martensite Steel for Steam Turbine LP Blade

NASA Astrophysics Data System (ADS)

Tianjian, Wang; Yubing, Pei; Zhenhuan, Gao; Hua, Fan; Gongxian, Yang

With the development of capacity and efficiency of coal-fired thermal power plant, the length of Low Pressure (LP) last-stage blade of steam turbine became longer. Therefore, the design static stress of blade gets closer or even higher than the yield strength of material. Because of the special operation condition of LP last stage blade, the stress corrosion crack of 12Cr-Ni-Mo-V-N Martensite stainless steel may happen especially at the root of the blade where designed the highest static stress. In this paper, the stress corrosion behavior of 12Cr-Ni-Mo-V-N Martensite stainless steels used for steam turbine LP last stage blade in 3vol% NaCl solution was studied, the constant stress is about 95%, 85%, 65% and 35% of yield stress respectively and the test was lasted for 3000 hours, the stress corrosion behavior was studied and then, the effect of shot penning strengthen for anti-stress corrosion property of 12Cr-Ni-Mo-V-N Martensitic steel was studied. The results showed that the purity of steel affects the stress corrosion behavior huge especially at the high and medium stress condition. The shot penning cannot enhances the anti-stress corrosion property of the 12Cr-Ni-Mo-V-N steel at high tensile constant stress condition, however it will make the anti-stress corrosion property better when the stress is low.

Corrosion behavior of a superduplex stainless steel in chloride aqueous solution

NASA Astrophysics Data System (ADS)

Dabalà, Manuele; Calliari, Irene; Variola, Alessandra

2004-04-01

Super duplex stainless steels (SDSS) have been widely used as structural materials for chemical plants (especially in those engaged in phosphoric acid production), in the hydrometallurgy industries, and as materials for offshore applications due to their excellent corrosion resistance in chloride environments, compared with other commercial types of ferritic stainless steels. These alloys also possess superior weldability and better mechanical properties than austenitic stainless steels. However, due to their two-phase structure, the nature of which is very dependent on their composition and thermal history, the behavior of SDSS regarding localized corrosion appears difficult to predict, especially in chloride environments. To improve their final properties, the effect of the partition of the alloying elements between the two phases, and the composition and microstructure of each phase are the key to understanding the localized corrosion phenomena of SDSS. This paper concerns the effects of the SDSS microstructure and heat treatment on the SDSS corrosion resistance in aqueous solutions, containing different amounts of NaCl at room temperature.

Natural Corrosion Inhibitors for Steel Reinforcement in Concrete — a Review

NASA Astrophysics Data System (ADS)

Raja, Pandian Bothi; Ghoreishiamiri, Seyedmojtaba; Ismail, Mohammad

2015-04-01

Reinforced concrete is one of the widely used construction materials for bridges, buildings, platforms and tunnels. Though reinforced concrete is capable of withstanding a large range of severe environments including marine, industrial and alpine conditions, there are still a large number of failures in concrete structures for many reasons. Either carbonation or chloride attack is the main culprit which is due to depassivation of reinforced steel and subsequently leads to rapid steel corrosion. Among many corrosion prevention measures, application of corrosion inhibitors play a vital role in metal protection. Numerous range of corrosion inhibitors were reported for concrete protection that were also used commercially in industries. This review summarizes the application of natural products as corrosion inhibitors for concrete protection and also scrutinizes various factors influencing its applicability.

Early Detection of Steel Rebar Corrosion by Acoustic Emission Monitoring

DOT National Transportation Integrated Search

1995-01-01

Acoustic emission monitoring was performed in a unique way on concrete specimens containing reinforcing steel and the acoustic emission events correlated with the presence of rebar corrosion. Verification of rebar corrosion was done by galvanic curre...

Corrosion performance tests for reinforcing steel in concrete : test procedures.

DOT National Transportation Integrated Search

2009-09-01

The existing test method to assess the corrosion performance of reinforcing steel embedded in concrete, mainly : ASTM G109, is labor intensive, time consuming, slow to provide comparative results, and often expensive. : However, corrosion of reinforc...

Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels

DOT National Transportation Integrated Search

1997-05-01

This data analysis was undertaken to investigate the weatherability of steels whose compositions do not fall in the range of ASTM Standard G101, Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels.

Corrosion performance tests for reinforcing steel in concrete : technical report.

DOT National Transportation Integrated Search

2009-10-01

The existing test method used to assess the corrosion performance of reinforcing steel embedded in : concrete, mainly ASTM G 109, is labor intensive, time consuming, slow to provide comparative results, : and can be expensive. However, with corrosion...

Stress-Corrosion Cracking in Martensitic PH Stainless Steels

NASA Technical Reports Server (NTRS)

Humphries, T.; Nelson, E.

1984-01-01

Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

Corrosion behavior of ODS steels with several chromium contents in hot nitric acid solutions

NASA Astrophysics Data System (ADS)

Tanno, Takashi; Takeuchi, Masayuki; Ohtsuka, Satoshi; Kaito, Takeji

2017-10-01

Oxide dispersion strengthened (ODS) steel cladding tubes have been developed for fast reactors. Tempered martensitic ODS steels with 9 and 11 wt% of chromium (9Cr-, 11Cr-ODS steel) are the candidate material in research being carried out at JAEA. In this work, fundamental immersion tests and electrochemical tests of 9 to 12Cr-ODS steels were systematically conducted in various nitric acid solutions at 95 °C. The corrosion rate decreased exponentially with effective solute chromium concentration (Creff) and nitric acid concentration. Addition of vanadium (V) and ruthenium (Ru) also decreased the corrosion rate. The combination of low Creff and dilute nitric acid could not avoid the active mass dissolution during active domain at the beginning of immersion, and the corrosion rate was high. Higher Creff decreased the partial anodic current during the active domain and assisted the passivation of the surface of the steel. Concentrated nitric acid and addition of Ru and V increased partial cathodic current and shifted the corrosion potential to noble side. These effects should have prevented the active mass dissolution and decreased the corrosion rate.

Corrosion susceptibility of steel drums to be used as containers for intermediate level nuclear waste

NASA Astrophysics Data System (ADS)

Farina, S.; Schulz Rodriguez, F.; Duffó, G.

2013-07-01

The present work is a study of the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins contaminated with different types and concentrations of aggressive species. A special type of specimen was manufactured to simulate the cemented ion-exchange resins in the drum. The evolution of the corrosion potential and the corrosion rate of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 900 days. The aggressive species studied were chloride ions (the main ionic species of concern) and sulphate ions (produced during radiolysis of the cationic exchange-resins after cementation). The work was complemented with an analysis of the corrosion products formed on the steel in each condition, as well as the morphology of the corrosion products. When applying the results obtained in the present work to estimate the corrosion depth of the steel drumscontaining the cemented radioactive waste after a period of 300 years (foreseen durability of the Intermediate Level Radioactive Waste facility in Argentina) , it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums.

Alkali activated slag mortars provide high resistance to chloride-induced corrosion of steel

NASA Astrophysics Data System (ADS)

Criado, Maria; Provis, John L.

2018-06-01

The pore solutions of alkali-activated slag cements and Portland-based cements are very different in terms of their chemical and redox characteristics, particularly due to the high alkalinity and high sulfide content of alkali-activated slag cement. Therefore, differences in corrosion mechanisms of steel elements embedded in these cements could be expected, with important implications for the durability of reinforced concrete elements. This study assesses the corrosion behaviour of steel embedded in alkali-activated blast furnace slag (BFS) mortars exposed to alkaline solution, alkaline chloride-rich solution, water, and standard laboratory conditions, using electrochemical techniques. White Portland cement (WPC) mortars and blended cement mortars (white Portland cement and blast furnace slag) were also tested for comparative purposes. The steel elements embedded in immersed alkali-activated slag mortars presented very negative redox potentials and high apparent corrosion current values; the presence of sulfide reduced the redox potential, and the oxidation of the reduced sulfur-containing species within the cement itself gave an electrochemical signal that classical electrochemical tests for reinforced concrete durability would interpret as being due to steel corrosion processes. However, the actual observed resistance to chloride-induced corrosion was very high, as measured by extraction and characterisation of the steel at the end of a 9-month exposure period, whereas the steel embedded in white Portland cement mortars was significantly damaged under the same conditions.

The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

NASA Astrophysics Data System (ADS)

Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J. R.; Figueroa, Carlos A.

2013-09-01

The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

The Corrosion Behavior of Cold Sprayed Zinc Coatings on Mild Steel Substrate

NASA Astrophysics Data System (ADS)

Chavan, Naveen Manhar; Kiran, B.; Jyothirmayi, A.; Phani, P. Sudharshan; Sundararajan, G.

2013-04-01

Zinc and its alloy coatings have been used extensively for the cathodic protection of steel. Zinc coating corrodes in preference to the steel substrate due to its negative corrosion potential. Numerous studies have been conducted on the corrosion behavior of zinc and its alloy coatings deposited using several techniques viz., hot dip galvanizing, electrodeposition, metalizing or thermal spray etc. Cold spray is an emerging low temperature variant of thermal spray family which enables deposition of thick, dense, and pure coatings at a rapid rate with an added advantage of on-site coating of steel structures. In the present study, the corrosion characteristics of cold sprayed zinc coatings have been investigated for the first time. In addition, the influence of heat treatment of zinc coating at a temperature of 150 °C on its corrosion behavior has also been addressed.

A Novel Optical Fiber Sensor for Steel Corrosion in Concrete Structures.

PubMed

Leung, Christopher K Y; Wan, Kai Tai; Chen, Liquan

2008-03-20

Steel corrosion resulting from the penetration of chloride ions or carbon dioxide is a major cause of degradation for reinforced concrete structures,. The objective of the present investigation was to develop a low-cost sensor for steel corrosion, which is based on a very simple physical principle. The flat end of a cut optical fiber is coated with an iron thin film using the ion sputtering technique. Light is then sent into a fiber embedded in concrete and the reflected signal is monitored. Initially, most of the light is reflected by the iron layer. When corrosion occurs to remove the iron layer, a significant portion of the light power will leave the fiber at its exposed end, and the reflected power is greatly reduced. Monitoring of the reflected signal is hence an effective way to assess if the concrete environment at the location of the fiber tip may induce steel corrosion or not. In this paper, first the principle of the corrosion sensor and its fabrication are described. The sensing principle is then verified by experimental results. Sensor packaging for practical installation will be presented and the performance of the packaged sensors is assessed by additional experiments.

A Novel Optical Fiber Sensor for Steel Corrosion in Concrete Structures

PubMed Central

Leung, Christopher K.Y.; Wan, Kai Tai; Chen, Liquan

2008-01-01

Steel corrosion resulting from the penetration of chloride ions or carbon dioxide is a major cause of degradation for reinforced concrete structures,. The objective of the present investigation was to develop a low-cost sensor for steel corrosion, which is based on a very simple physical principle. The flat end of a cut optical fiber is coated with an iron thin film using the ion sputtering technique. Light is then sent into a fiber embedded in concrete and the reflected signal is monitored. Initially, most of the light is reflected by the iron layer. When corrosion occurs to remove the iron layer, a significant portion of the light power will leave the fiber at its exposed end, and the reflected power is greatly reduced. Monitoring of the reflected signal is hence an effective way to assess if the concrete environment at the location of the fiber tip may induce steel corrosion or not. In this paper, first the principle of the corrosion sensor and its fabrication are described. The sensing principle is then verified by experimental results. Sensor packaging for practical installation will be presented and the performance of the packaged sensors is assessed by additional experiments. PMID:27879805

Corrosion control for reinforced concrete

NASA Astrophysics Data System (ADS)

Torigoe, R. M.

The National Bureau of Standards has recorded that in 1975 the national cost of corrosion was estimated at $70 billion. Approximately 40% of that total was attributed to the corrosion of steel reinforcements in concrete. Though concrete is generally perceived as a permanent construction material, cracking and spalling can occur when corrosion of steel reinforcements progresses to an advanced stage. This problem frequently occurs in reinforced concrete highway bridge decks, wharves, piers, and other structures in marine and snowbelt environments. Since concrete has a very low tensile strength, steel reinforcements are added to carry the tensile load of the composite member. Corrosion reduces the effective diameter of the reinforcements and, therefore, decreases the load carrying capability of the member. Though the corrosion process may occur in various forms and may be caused by different sources, the ultimate result is still the failure of the reinforced concrete.

Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

NASA Astrophysics Data System (ADS)

Tang, Fujian

This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

Wire-Arc-Sprayed Aluminum Protects Steel Against Corrosion

NASA Technical Reports Server (NTRS)

Zimmerman, Frank R.; Poorman, Richard; Sanders, Heather L.; Mckechnie, Timothy N.; Bonds, James W., Jr.; Daniel, Ronald L., Jr.

1995-01-01

Aluminum coatings wire-arc sprayed onto steel substrates found effective in protecting substrates against corrosion. Coatings also satisfy stringent requirements for adhesion and flexibility, both at room temperature and at temperatures as low as liquid hydrogen. Developed as alternatives to corrosion-inhibiting primers and paints required by law to be phased out because they contain and emit such toxic substances as chromium and volatile organic compounds.

Mechanical and Microstructural Characterization of a New Corrosion Resistant Stainless Steel

NASA Astrophysics Data System (ADS)

Voiculescu, I.; Geantă, V.; Stefănoiu, R.; Cotruţ, C.; Ciocoiu, R.; Ionescu, M.

2018-06-01

The paper investigates the manner in which the chemical composition and delivery status of a new type of stainless steel, highly alloyed with Ni and Cr, affect mechanical properties, microstructure and corrosion resistance. The results obtained during the mechanical test (tensile, compression, Charpy test and micro-hardness) have revealed promising values. During the corrosion test, the preferential attack of the reagent (Aqua regia) located on the grain boundaries, inclusions or polyhedral precipitates have been observed. On the corroded surfaces, some localized pitting effects on grain boundaries have been revealed. The analyses of the parameter values recorded during the corrosion test revealed that the corrosion current density had a low value, comparable to that of other specific types of stainless steels. The actual Icorr (1.089 µA/cm2) value measured for the experimental alloy proves good resistance to corrosion in 3% NaCl saline solution. The estimated rate of corrosion presented acceptable values (0.011 mm/year).

Chloride-induced corrosion mechanism and rate of enamel- and epoxy-coated deformed steel bars embedded in mortar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Fujian; Chen, Genda; Brow, Richard K.

The chloride-induced corrosion mechanisms of uncoated, pure enamel (PE)-coated, mixed enamel (ME)-coated, double enamel (DE)-coated, and fusion bonded epoxy (FBE)-coated deformed steel bars embedded in mortar cylinders are investigated in 3.5 wt.% NaCl solution and compared through electrochemical tests and visual inspection. Corrosion initiated after 29 or 61 days of tests in all uncoated and enamel-coated steel bars, and after 244 days of tests in some FBE-coated steel bars. In active stage, DE- and FBE-coated steel bars are subjected to the highest and lowest corrosion rates, respectively. The uncoated and ME-coated steel bars revealed relatively uniform corrosion while the PE-,more » DE-, and FBE-coated steel bars experienced pitting corrosion around damaged coating areas. Due to the combined effect of ion diffusion and capillary suction, wet–dry cyclic immersion caused more severe corrosion than continuous immersion. Both exposure conditions affected the corrosion rate more significantly than the water–cement ratio in mortar design.« less

Structural modifications and corrosion behavior of martensitic stainless steel nitrided by plasma immersion ion implantation

NASA Astrophysics Data System (ADS)

Figueroa, C. A.; Alvarez, F.; Zhang, Z.; Collins, G. A.; Short, K. T.

2005-07-01

In this work we report a study of the structural modifications and corrosion behavior of martensitic stainless steels (MSS) nitrided by plasma immersion ion implantation (PI3). The samples were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, photoemission electron spectroscopy, and potentiodynamic electrochemical measurements. Depending on the PI3 treatment temperature, three different material property trends are observed. At lower implantation temperatures (e.g., 360 °C), the material corrosion resistance is improved and a compact phase of ɛ-(Fe,Cr)3N, without changes in the crystal morphology, is obtained. At intermediate temperatures (e.g., 430 °C), CrN precipitates form principally at grain boundaries, leading to a degradation in the corrosion resistance compared to the original MSS material. At higher temperatures (e.g., 500 °C), the relatively great mobility of the nitrogen and chromium in the matrix induced random precipitates of CrN, transforming the original martensitic phase into α-Fe (ferrite), and causing a further degradation in the corrosion resistance.

Coated steel rebar for enhanced concrete-steel bond strength and corrosion resistance.

DOT National Transportation Integrated Search

2010-10-01

This report summarizes the findings and recommendations on the use of enamel coating in reinforced concrete structures both for bond strength and : corrosion resistance of steel rebar. Extensive laboratory tests were conducted to characterize the pro...

Stainless steel corrosion by molten nitrates : analysis and lessons learned.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruizenga, Alan Michael

2011-09-01

A secondary containment vessel, made of stainless 316, failed due to severe nitrate salt corrosion. Corrosion was in the form of pitting was observed during high temperature, chemical stability experiments. Optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were all used to diagnose the cause of the failure. Failure was caused by potassium oxide that crept into the gap between the primary vessel (alumina) and the stainless steel vessel. Molten nitrate solar salt (89% KNO{sub 3}, 11% NaNO{sub 3} by weight) was used during chemical stability experiments, with an oxygen cover gas, at a salt temperature of 350-700 C.more » Nitrate salt was primarily contained in an alumina vessel; however salt crept into the gap between the alumina and 316 stainless steel. Corrosion occurred over a period of approximately 2000 hours, with the end result of full wall penetration through the stainless steel vessel; see Figures 1 and 2 for images of the corrosion damage to the vessel. Wall thickness was 0.0625 inches, which, based on previous data, should have been adequate to avoid corrosion-induced failure while in direct contact with salt temperature at 677 C (0.081-inch/year). Salt temperatures exceeding 650 C lasted for approximately 14 days. However, previous corrosion data was performed with air as the cover gas. High temperature combined with an oxygen cover gas obviously drove corrosion rates to a much higher value. Corrosion resulted in the form of uniform pitting. Based on SEM and EDS data, pits contained primarily potassium oxide and potassium chromate, reinforcing the link between oxides and severe corrosion. In addition to the pitting corrosion, a large blister formed on the side wall, which was mainly composed of potassium, chromium and oxygen. All data indicated that corrosion initiated internally and moved outward. There was no evidence of intergranular corrosion nor were there any indication of fast pathways along grain boundaries. Much

Structure and properties of corrosion and wear resistant Cr-Mn-N steels

NASA Astrophysics Data System (ADS)

Lenel, U. R.; Knott, B. R.

1987-06-01

Steels containing about 12 pct Cr, 10 pct Mn, and 0.2 pct N have been shown to have an unstable austenitic microstructure and have good ductility, extreme work hardening, high fracture strength, excellent toughness, good wear resistance, and moderate corrosion resistance. A series of alloys containing 9.5 to 12.8 pct Cr, 5.0 to 10.4 pct Mn, 0.16 to 0.32 pct N, 0.05 pct C, and residual elements typical of stainless steels was investigated by microstructural examination and mechanical, abrasion, and corrosion testing. Microstructures ranged from martensite to unstable austenite. The unstable austenitic steels transformed to α martensite on deformation and displayed very high work hardening, exceeding that of Hadfield’s manganese steels. Fracture strengths similar to high carbon martensitic stainless steels were obtained while ductility and toughness values were high, similar to austenitic stainless steels. Resistance to abrasive wear exceeded that of commercial abrasion resistant steels and other stainless steels. Corrosion resistance was similar to that of other 12 pct Cr steels. Properties were not much affected by minor compositional variations or rolled-in nitrogen porosity. In 12 pct Cr-10 pct Mn alloys, ingot porosity was avoided when nitrogen levels were below 0.19 pet, and austenitic microstructures were obtained when nitrogen levels exceeded 0.14 pct.

Corrosion Behavior of Metal Active Gas Welded Joints of a High-Strength Steel for Automotive Application

NASA Astrophysics Data System (ADS)

Garcia, Mainã Portella; Mantovani, Gerson Luiz; Vasant Kumar, R.; Antunes, Renato Altobelli

2017-10-01

In this work, the corrosion behavior of metal active gas-welded joints of a high-strength steel with tensile yield strength of 900 MPa was investigated. The welded joints were obtained using two different heat inputs. The corrosion behavior has been studied in a 3.5 wt.% NaCl aqueous solution using electrochemical impedance spectroscopy and potentiodynamic polarization tests. Optical microscopy images, scanning electron microscopy and transmission electron microscopy with energy-dispersive x-ray revealed different microstructural features in the heat-affected zone (HAZ) and the weld metal (WM). Before and after the corrosion process, the sample was evaluated by confocal laser scanning microscopy to measure the depth difference between HAZ and WM. The results showed that the heat input did not play an important role on corrosion behavior of HSLA steel. The anodic and cathodic areas of the welded joints could be associated with depth differences. The HAZ was found to be the anodic area, while the WM was cathodic with respect to the HAZ. The corrosion behavior was related to the amount and orientation nature of carbides in the HAZ. The microstructure of the HAZ consisted of martensite and bainite, whereas acicular ferrite was observed in the weld metal.

Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

PubMed

Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

2016-11-01

In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface. Copyright © 2016 Elsevier B.V. All rights reserved.

Corrosion behavior of surface films on boron-implanted high purity iron and stainless steels

NASA Technical Reports Server (NTRS)

Kim, H. J.; Carter, W. B.; Hochman, R. F.; Meletis, E. I.

1985-01-01

Boron (dose, 2 x 10 to the 17th ions/sq cm) was implanted into high purity iron, AISI 316 austenitic stainless steel, and AISI 440C martensitic stainless steel, at 40 keV. The film structure of implanted samples was examined and characterized by contrast and diffraction analyses utilizing transmission electron microscopy. The effect of B(+) ion implantation on the corrosion behavior was studied using the potentiodynamic polarization technique. Tests were performed in deaerated 1 N H2SO4 and 0.1 M NaCl solutions. Scanning electron microscopy was used to examine the morphology of the corroded surfaces after testing.

Improvement of corrosion resistance of low-alloy steels by resurfacing using multifunction cavitation in water

NASA Astrophysics Data System (ADS)

Ijiri, Masataka; Yoshimura, Toshihiko

2018-02-01

Low-alloy steels are based on carbon steel in combination with several percent or less (in many cases, 1 mass%) alloying elements, and they offer improved resistance to corrosion at a cost slightly higher than that of carbon steel. However, these materials do not exhibit the same corrosion resistance as stainless steel. The authors have previously developed a novel multifunction cavitation (MFC) technique, which combines ultrasonic cavitation with water jet cavitation. In this study, MFC was used to modify the surface of Cr-Mo steel (SCM435) and Ni-Cr-Mo steel (SNCM630). MFC was found to improve the residual stress value of the material as the result of surface modification while also imparting high strength and superior corrosion resistance.

Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

NASA Astrophysics Data System (ADS)

Yenilmez, A.; Karakan, M.; Çelik, İ.

2017-01-01

Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides

USDA-ARS?s Scientific Manuscript database

Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

Mechanical behavior of precipitation hardenable steels exposed to highly corrosive environment

NASA Technical Reports Server (NTRS)

Rosa, Ferdinand

1994-01-01

Unexpected occurrences of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15 - 5 PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a 3.5 percent NaCl aqueous solution. The material selected for the study was 15 - 5 PH steel in the H 900 condition. The Slow Strain Rate technique was used to test the metallic specimens.

Corrosion Behavior of Low-C Medium-Mn Steel in Simulated Marine Immersion and Splash Zone Environment

NASA Astrophysics Data System (ADS)

Zhang, Dazheng; Gao, Xiuhua; Su, Guanqiao; Du, Linxiu; Liu, Zhenguang; Hu, Jun

2017-05-01

The corrosion behavior of low-C medium-Mn steel in simulated marine immersion and splash zone environment was studied by static immersion corrosion experiment and wet-dry cyclic corrosion experiment, respectively. Corrosion rate, corrosion products, surface morphology, cross-sectional morphology, elemental distribution, potentiodynamic polarization curves and electrochemical impedance spectra were used to elucidate the corrosion behavior of low-C medium-Mn steel. The results show that corrosion rate in immersion zone is much less than that in splash zone owing to its relatively mild environment. Manganese compounds are detected in the corrosion products and only appeared in splash zone environment, which can deteriorate the protective effect of rust layer. With the extension of exposure time, corrosion products are gradually transformed into dense and thick corrosion rust from the loose and porous one in these two environments. But in splash zone environment, alloying elements of Mn appear significant enrichment in the rust layer, which decrease the corrosion resistance of the steel.

Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

PubMed

Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

2011-01-01

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

PubMed Central

Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

2011-01-01

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring. PMID:22346672

Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin

PubMed Central

Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Hammed, Leiqaa A.; Al-Amiery, Ahmed A.; San, Ng Hooi; Musa, Ahmed Y.

2014-01-01

A new coumarin derivative, N,N′-((2E,2′E)-2,2′-(1,4-phenylenebis(methanylylidene))bis(hydrazinecarbonothioyl))bis(2-oxo-2H-chromene-3-carboxamide) PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear magnetic resonance, 1H-NMR and carbon-13 nuclear magnetic resonance 13C-NMR). The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential (ECORR), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM) was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH. PMID:28788680

Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin.

PubMed

Kadhum, Abdul Amir H; Mohamad, Abu Bakar; Hammed, Leiqaa A; Al-Amiery, Ahmed A; San, Ng Hooi; Musa, Ahmed Y

2014-06-05

A new coumarin derivative, N , N '-((2E,2'E)-2,2'-(1,4-phenylenebis (methanylylidene))bis(hydrazinecarbonothioyl))bis(2-oxo-2H-chromene-3-carboxamide) PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear magnetic resonance, 1 H-NMR and carbon-13 nuclear magnetic resonance 13 C-NMR). The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential ( E CORR ), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM) was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH.

Temperature Effects on Stainless Steel 316L Corrosion in the Environment of Sulphuric Acid (H2SO4)

NASA Astrophysics Data System (ADS)

Ayu Arwati, I. G.; Herianto Majlan, Edy; Daud, Wan Ramli Wan; Shyuan, Loh Kee; Arifin, Khuzaimah Binti; Husaini, Teuku; Alfa, Sagir; Ashidiq, Fakhruddien

2018-03-01

In its application, metal is always in contact with its environment whether air, vapor, water, and other chemicals. During contact, chemical interactions emerge between metals and their respective environments such that the metal surface corrodes. This study aims to determine the corrosion rate of 316L stainless steel sulphuric acid environment (H2SO4) with weight loss and electrochemical methods. The corrosion rate (CR) is value of 316L stainless steel by weight loss method with sulfuric acid (H2SO4) with concentration of 0.5 M. The result obtained in conjunction with the increase of temperature the rate of erosion obtained appears to be larger, with a consecutive 3 hour the temperature of 50°C is 0.27 mg/cm2h, temperature 70°C 0.38 mg/cm2h, and temperature 90 °C 0.52 mg/cm2h. With the electrochemical method, the current value increases by using a C350 potentiostal tool. The higher the current, the longer the time the corrosion rate increases, where the current is at 90 °C with a 10-minute treatment time of 0.0014736 A. The 316L stainless steel in surface metal morphology is shown by using a Scanning Electron Microscope (SEM).

Influence of Changes in Water-to-Cement Ratio, Alkalinity, Concrete Fluidity, Voids, and Type of Reinforcing Steel on the Corrosion Potential of Steel in Concrete.

DOT National Transportation Integrated Search

2014-04-01

"Research on steel corrosion has demonstrated that the concentrations of chloride and hydroxide ion at the concrete/steel : interface influence the susceptibility of the steel to corrosive attack. This study used electrochemical means and changes in ...

Corrosion behavior of oxide dispersion strengthened ferritic steels in supercritical water

NASA Astrophysics Data System (ADS)

Gao, Wenhua; Guo, Xianglong; Shen, Zhao; Zhang, Lefu

2017-04-01

The corrosion resistance of three different Cr content oxide dispersion strengthened (ODS) ferritic steels in supercritical water (SCW) and their passive films formed on the surface have been investigated. The results show that the dissolved oxygen (DO) and chemical composition have significant influence on the corrosion behavior of the ODS ferritic steels. In 2000 ppb DO SCW at 650 °C, the 14Cr-4Al ODS steel forms a tri-layer oxide film and the surface morphologies have experienced four structures. For the tri-layer oxide film, the middle layer is mainly Fe-Cr spinel and the Al is gradually enriched in the inner layer.

Phased array ultrasonic steel corrosion mapping for bridges and ancillary structures.

DOT National Transportation Integrated Search

2017-08-01

Steel corrosion on bridges and ancillary structures due to environmental effects and deicing chemicals is a serious problem for Minnesota's infrastructure. The ability to detect, locate, and measure corrosion is an important aspect of structure inspe...

Study on electrochemical corrosion mechanism of steel foot of insulators for HVDC lines

NASA Astrophysics Data System (ADS)

Zheng, Weihua; Sun, Xiaoyu; Fan, Youping

2017-09-01

The main content of this paper is the mechanism of electrochemical corrosion of insulator steel foot in HVDC transmission line, and summarizes five commonly used artificial electrochemical corrosion accelerated test methods in the world. Various methods are analyzed and compared, and the simulation test of electrochemical corrosion of insulator steel feet is carried out by water jet method. The experimental results show that the experimental environment simulated by water jet method is close to the real environment. And the three suspension modes of insulators in the actual operation, the most serious corrosion of the V type suspension hardware, followed by the tension string suspension, and the linear string corrosion rate is the slowest.

Effect of Atmospheric Corrosion on the Mechanical Properties of SAE 1020 Structural Steel.

PubMed

Martínez, Carola; Briones, Francisco; Villarroel, María; Vera, Rosa

2018-04-11

Resistance to atmospheric corrosion in different environments located in Chile and the corrosion's effect on the mechanical properties of SAE 1020 steel were studied. Atmospheric corrosivity categories at each station under study were determined. These categories were C2, for Laja; C3 and C4, for the Arica and Antarctic stations, respectively; and the most aggressive, C5 and higher at Quintero. These specific environments significantly influenced the mechanical responses of steel exposed for 36 months. Rupture elongation, the modulus of toughness, ultimate tensile strength, and hardness of the material all decreased as a function of environmental atmospheric aggressiveness. Lowered ductility is the result of the increased corrosion rate due to the high deposition of chlorides. This is due to the morphology of material degradation, which consequently occurs as pores, microstrains, and other defects that promote early rupture of the steel.

Development of Ferrium S53 High-Strength, Corrosion-Resistant Steel

DTIC Science & Technology

2009-01-01

strength steel used in landing gear, and equivalent in corrosion resistance to the lower strength 15-5PH stainless steel used in actuators. It also...5PH stainless steel used in modern aerospace actuators. These objectives were met, with two minor exceptions: (1) the tensile yield of S53 is... stainless steel used in modern aerospace actuators. The work was initially funded as a 1-year SERDP proof-of-principle project. In this first

Demonstration and Validation of Stainless Steel Materials for Critical Above Grade Piping in Highly Corrosive Locations

DTIC Science & Technology

2017-05-01

Protecting And Bonding Reinforcing Steel In Cement -Based Composites, Corrosion 2009, Atlanta, GA, 22-26 March 2009. 7. Hock, V., O. Marshall, S...ER D C/ CE RL T R- 17 -1 3 DoD Corrosion Prevention and Control Program Demonstration and Validation of Stainless Steel Materials for...ERDC/CERL TR-17-13 May 2017 Demonstration and Validation of Stainless Steel Materials for Critical Above-Grade Piping in Highly Corrosive

Improving Corrosion Resistance of 316L Austenitic Stainless Steel Using ZrO2 Sol-Gel Coating in Nitric Acid Solution

NASA Astrophysics Data System (ADS)

Kazazi, Mahdi; Haghighi, Milad; Yarali, Davood; Zaynolabedini, Masoomeh H.

2018-03-01

In this study, thin-film coating of zirconium oxide (ZrO2) was prepared by sol-gel method and subsequent heat treatment process. The sol was prepared by controlled hydrolysis of zirconium tetrapropoxide using acetic acid and ethanol/acetylacetone mixture as catalyst and chelating agent, respectively, and finally deposited onto the 316L austenitic stainless steel (316L SS) using dip coating method in order to improve its corrosion resistance in nitric acid medium. The composition, structure, and morphology of the coated surface were investigated by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The obtained results from XRD and FTIR state the formation of tetragonal and monoclinic ZrO2 phase. Also, the obtained results from surface morphology investigation by SEM and AFM indicate the formation of smooth, homogeneous and uniform coatings on the steel substrate. Then, the corrosion behavior of stainless steel was investigated in a 1 and 10 M nitric acid solutions using electrochemical impedance spectroscopy and linear polarization test. The obtained results from these tests for ZrO2-coated specimens indicated a considerable improvement in the corrosion resistance of 316L stainless steel by an increase in corrosion potential and transpassive potential, and a decrease in passive current density and corrosion current density. The decrease in passive current density in both the concentration of solutions was two orders of magnitude from bare to coated specimens.

Corrosion of Steel in a Black Mangrove Environment

DTIC Science & Technology

1982-10-01

neceaaary and Identify by block number) Black Mangrove Environment Chloride Salts Corrosion Iron- Tannin Complex Steel Tannic Acid Tropic Test Center...identified to be as follows: rain water falling through the mangrove canopy picks up salts and tannins from the black mangroves. The salts...attack steel, forming water-soluble ferric ions. The tannins react DD , JAN 73 •*/J EDITION OF » MOV 65 IS OBSOLETE UNCLASSIFIED SECURITY

Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

NASA Astrophysics Data System (ADS)

Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

2012-10-01

The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

X-ray photoelectron spectroscopy and electrochemical studies of mild steel FeE500 passivation in concrete simulated water

NASA Astrophysics Data System (ADS)

Miserque, F.; Huet, B.; Azou, G.; Bendjaballah, D.; L'Hostis, V.

2006-11-01

In the context of the prediction of the long-term behaviour of reinforced concrete structures involved in the nuclear waste storage, the corrosion mechanisms of steels have to be assessed. When mild steel rebars are embedded in concrete, the chemical environment of the reinforcement is progressively modified, due to the carbonation of the concrete matrix. This modification leads to the variation of iron oxides properties formed at the steel/concrete interface, and the active corrosion can be initiated. The aim of this study is to evaluate the passivation behaviour and to provide insights into the depassivation of mild steel in concrete pore solution. In a young concrete, due to the alkalinity of the interstitial solution, steel reinforcement remains passive. Immersion tests of mild steel substrate in various alkaline solutions (from pH 13 to 10) have been performed. Due to the low thickness of the corrosion layers formed, X-ray photoelectron spectroscopy has been used to characterize them. In the passive domain, the corrosion products are similar for the various solutions. The corrosion layer is composed of a mixture of Fe3+ and Fe2+. A similar approach is used to determine the depassivation mechanism. The effect of various components such as carbonates, sulfates and silicates resulting from the dissolution of minerals of cement during the carbonation process is investigated. In addition to the surface analysis, the evolution of the electrochemical behaviour as function of the solution nature (pH) is evaluated with the help of electrochemical measurements (free corrosion potential, cyclic voltamperometry).

Stainless Steel Corrosion Studies Final Report: FY17 End of-Year

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Daniel; Milenski, Helen Marie; Martinez, Destiny

Two materials are being considered in applications requiring their contact against stainless steel surfaces. These materials include the solvent methyl ethyl ketone (MEK), and the polymer neoprene (polychloroprene). There is concern that contact of these materials with stainless steel substrates may lead to corrosion. To address these concerns we have undertaken corrosion studies under conditions expected to be more aggressive than in intended applications. These conditions include elevated temperature and humidity, and submersion and suspension in solvent vapors, in an attempt to accelerate any potential deleterious interactions. Corrosion rates below 0.1 mpy have historically been deemed INSIGNIFICANT from a WRmore » Production standpoint; corresponding guidelines for non-production applications are lacking.« less

Corrosion susceptibility of steel drums containing cemented intermediate level nuclear wastes

NASA Astrophysics Data System (ADS)

Duffó, Gustavo S.; Farina, Silvia B.; Schulz, Fátima M.; Marotta, Francesca

2010-10-01

Cementation processes are used as immobilization techniques for low or intermediate level radioactive waste for economical and safety reasons and for being a simple operation. In particular, ion-exchange resins commonly used for purification of radioactive liquid waste from nuclear reactors are immobilized before being stored to improve the leach resistance of the waste matrix and to maintain mechanical stability. Combustible solid radioactive waste can be incinerated and the resulting ashes can also be immobilized before storage. The immobilized resins and ashes are then contained in steel drums that may undergo corrosion depending on the presence of certain contaminants. The work described in this paper was aimed at evaluating the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins and incineration ashes containing different concentrations of aggressive species (mostly chloride and sulphate ions). A special type of specimen was designed to simulate the cemented waste in the drum. The evolution of the corrosion potential and the corrosion current density of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 1 year. The results show the deleterious effect of chloride on the expected lifespan of the waste containers.

Multicomponent Synthesis and Evaluation of New 1,2,3-Triazole Derivatives of Dihydropyrimidinones as Acidic Corrosion Inhibitors for Steel.

PubMed

González-Olvera, Rodrigo; Román-Rodríguez, Viridiana; Negrón-Silva, Guillermo E; Espinoza-Vázquez, Araceli; Rodríguez-Gómez, Francisco Javier; Santillan, Rosa

2016-02-22

An efficient one-pot synthesis of 1,2,3-triazole derivatives of dihydropyrimidinones has been developed using two multicomponent reactions. The aldehyde-1,2,3-triazoles were obtained in good yields from in situ-generated organic azides and O-propargylbenzaldehyde. The target heterocycles were synthesized through the Biginelli reaction in which the aldehyde-1,2,3-triazoles reacted with ethyl acetoacetate and urea in the presence of Ce(OTf)₃ as the catalyst. The corrosion inhibition of steel grade API 5 L X52 in 1 M HCl by the synthesized compounds was investigated using the electrochemical impedance spectroscopy technique. The measurements revealed that these heterocycles are promising candidates to inhibit acidic corrosion of steel.

Microbiologically Influenced Corrosion of 2707 Hyper-Duplex Stainless Steel by Marine Pseudomonas aeruginosa Biofilm

PubMed Central

Li, Huabing; Zhou, Enze; Zhang, Dawei; Xu, Dake; Xia, Jin; Yang, Chunguang; Feng, Hao; Jiang, Zhouhua; Li, Xiaogang; Gu, Tingyue; Yang, Ke

2016-01-01

Microbiologically Influenced Corrosion (MIC) is a serious problem in many industries because it causes huge economic losses. Due to its excellent resistance to chemical corrosion, 2707 hyper duplex stainless steel (2707 HDSS) has been used in the marine environment. However, its resistance to MIC was not experimentally proven. In this study, the MIC behavior of 2707 HDSS caused by the marine aerobe Pseudomonas aeruginosa was investigated. Electrochemical analyses demonstrated a positive shift in the corrosion potential and an increase in the corrosion current density in the presence of the P. aeruginosa biofilm in the 2216E medium. X-ray photoelectron spectroscopy (XPS) analysis results showed a decrease in Cr content on the coupon surface beneath the biofilm. The pit imaging analysis showed that the P. aeruginosa biofilm caused a largest pit depth of 0.69 μm in 14 days of incubation. Although this was quite small, it indicated that 2707 HDSS was not completely immune to MIC by the P. aeruginosa biofilm. PMID:26846970

Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

NASA Astrophysics Data System (ADS)

Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

2016-04-01

Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

Corrosion behavior of austenitic steels and their components in niobium-containing chloride melts

NASA Astrophysics Data System (ADS)

Abramov, A. V.; Polovov, I. B.; Rebrin, O. I.; Volkovich, V. A.; Lisienko, D. G.

2014-02-01

The mechanism of corrosion of austenitic steels 12Kh18N10T, 10Kh17N13M2T, and 03Kh17N14M3 and metals Cr, Fe, Ni, and Mo in a NaCl-KCl-NbCl n ( n = 3.5, Nb content is 5 ± 0.1 wt %) melt at 750°C is studied. The metal and steel corrosion rates under these conditions are determined. The character of material fracture and the mechanisms of material corrosion are found.

A Novel Hydrazinecarbothioamide as a Potential Corrosion Inhibitor for Mild Steel in HCl.

PubMed

Al-Amiery, Ahmed A; Kadhum, Abdul Amir H; Mohamad, Abu Bakar; Junaedi, Sutiana

2013-04-02

2-(1-methyl-4-((E)-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)-hydrazineecarbothioamide (HCB) was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectral data.

Bioengineered silver nanoparticles as potent anti-corrosive inhibitor for mild steel in cooling towers.

PubMed

Narenkumar, Jayaraman; Parthipan, Punniyakotti; Madhavan, Jagannathan; Murugan, Kadarkarai; Marpu, Sreekar Babu; Suresh, Anil Kumar; Rajasekar, Aruliah

2018-02-01

Silver nanoparticle-aided enhancement in the anti-corrosion potential and stability of plant extract as ecologically benign alternative for microbially induced corrosion treatment is demonstrated. Bioengineered silver nanoparticles (AgNPs) surface functionalized with plant extract material (proteinacious) was generated in vitro in a test tube by treating ionic AgNO 3 with the leaf extract of Azadirachta indica that acted as dual reducing as well as stabilizing agent. Purity and crystallinity of the AgNPs, along with physical and surface characterizations, were evaluated by performing transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive x-ray spectra, single-area electron diffractions, zeta potential, and dynamic light scattering measurements. Anti-corrosion studies against mild steel (MS1010) by corrosion-inducive bacterium, Bacillus thuringiensis EN2 isolated from cooling towers, were evaluated by performing electrochemical impedance spectroscopy (EIS), weight loss analysis, and surface analysis by infrared spectroscopy. Our studies revealed that AgNPs profoundly inhibited the biofilm on MS1010 surface and reduced the corrosion rates with the CR of 0.5 mm/y and an inhibition efficiency of 77% when compared to plant extract alone with a CR of 2.2 mm/y and an inhibition efficiency of 52%. Further surface analysis by infrared spectra revealed that AgNPs formed a protective layer of self-assembled film on the surface of MS1010. Additionally, EIS and surface analysis revealed that the AgNPs have inhibited the bacterial biofilm and reduced the pit on MS1010. This is the first report disclosing the application of bioengineered AgNP formulations as potent anti-corrosive inhibitor upon forming a protective layer over mild steel in cooling water towers. Graphical Abstract ᅟ.

Factors affecting the corrosivity of pulping liquors

NASA Astrophysics Data System (ADS)

Hazlewood, Patrick Evan

Increased equipment failures and the resultant increase in unplanned downtime as the result of process optimization programs continue to plague pulp mills. The failures are a result of a lack of understanding of corrosion in the different pulping liquors, specifically the parameters responsible for its adjustment such as the role and identification of inorganic and organic species. The current work investigates the role of inorganic species, namely sodium hydroxide and sodium sulfide, on liquor corrosivity at a range of process conditions beyond those currently experienced in literature. The role of sulfur species, in the activation of corrosion and the ability of hydroxide to passivate carbon steel A516-Gr70, is evaluated with gravimetric and electrochemical methods. The impact of wood chip weathering on process corrosion was also evaluated. Results were used to identify black liquor components, depending on the wood species, which play a significant role in the activation and inhibition of corrosion for carbon steel A516-Gr70 process equipment. Further, the effect of black liquor oxidation on liquor corrosivity was evaluated. Corrosion and stress corrosion cracking performance of selected materials provided information on classes of materials that may be reliably used in aggressive pulping environments.

Effect of Elemental Sulfur and Sulfide on the Corrosion Behavior of Cr-Mo Low Alloy Steel for Tubing and Tubular Components in Oil and Gas Industry.

PubMed

Khaksar, Ladan; Shirokoff, John

2017-04-20

The chemical degradation of alloy components in sulfur-containing environments is a major concern in oil and gas production. This paper discusses the effect of elemental sulfur and its simplest anion, sulfide, on the corrosion of Cr-Mo alloy steel at pH 2 and 5 during 10, 20 and 30 h immersion in two different solutions. 4130 Cr-Mo alloy steel is widely used as tubing and tubular components in sour services. According to the previous research in aqueous conditions, contact of solid sulfur with alloy steel can initiate catastrophic corrosion problems. The corrosion behavior was monitored by the potentiodynamic polarization technique during the experiments. Energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) have been applied to characterize the corrosion product layers after each experiment. The results show that under the same experimental conditions, the corrosion resistance of Cr-Mo alloy in the presence of elemental sulfur is significantly lower than its resistance in the presence of sulfide ions.

Detection of stress corrosion cracking and general corrosion of mild steel in simulated defense nuclear waste solutions using electrochemical noise analysis

NASA Astrophysics Data System (ADS)

Edgemon, G. L.; Danielson, M. J.; Bell, G. E. C.

1997-06-01

Underground waste tanks fabricated from mild steel store more than 253 million liters of high level radioactive waste from 50 years of weapons production at the Hanford Site. The probable modes of corrosion failures are reported as nitrate stress corrosion cracking and pitting. In an effort to develop a waste tank corrosion monitoring system, laboratory tests were conducted to characterize electrochemical noise data for both uniform and localized corrosion of mild steel and other materials in simulated waste environments. The simulated waste solutions were primarily composed of ammonium nitrate or sodium nitrate and were held at approximately 97°C. The electrochemical noise of freely corroding specimens was monitored, recorded and analyzed for periods ranging between 10 and 500 h. At the end of each test period, the specimens were examined to correlate electrochemical noise data with corrosion damage. Data characteristic of uniform corrosion and stress corrosion cracking are presented.

Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings.

PubMed

Eric Jones, John; Chen, Meng; Yu, Qingsong

2014-10-01

To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20-25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH₃/O₂ plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O- and N-contents on the surfaces were substantially increased after NH₃/O₂ plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH₃/O₂ plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. © 2014 Wiley Periodicals, Inc.

Corrosion inhibition of Q235 steel in 1 M HCl using quaternized tetraaniline as a corrosion inhibitor

NASA Astrophysics Data System (ADS)

Li, Xiangyu; Ye, Yuwei; Liu, Tong; Zheng, Wenru; Yang, Feng; Zhao, Haichao; Wang, Liping

2017-12-01

Novel quaternary ammonium cation containing tetraaniline (QATA) was successfully synthesized by condensation of amine-capped tetraaniline with 6-bromohexanoic acid, followed by quaternarization with triethylamine. The corrosion inhibition performance of QATA with their adsorption mechanisms for Q235 steel was studied in 1 M HCl solution by a series of methods such as weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The inhibition efficiency (IE%) increased with increasing concentrations of QATA, reaching a value up to 97.47% at a concentration of 150 mg l-1. Potentiodynamic polarization curves showed that the QATA affected both cathodic and anodic protection and was a mixed type inhibitor in 1 M HCl corrosive medium. Adsorption isotherm studies confirmed that the absorption of QATA on the Q235 steel surface in 1 M HCl solution obeyed Langmuir adsorption isotherm, and the adsorption process of corrosion inhibition on Q235 steel surface involved both the physical and chemical adsorption. The EDS analysis determined the adsorption of QATA molecules on the steel surface, the surface morphologies before and after immersion in 1 M HCl medium were also investigated by SEM and AFM.

Is cell viability always directly related to corrosion resistance of stainless steels?

PubMed

Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

2016-05-01

It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. Copyright © 2016 Elsevier B.V. All rights reserved.

75 FR 13490 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

... DEPARTMENT OF COMMERCE International Trade Administration (A-580-816) Certain Corrosion-Resistant... results of the antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat...

76 FR 15291 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-21

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant... results of the antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat...

A discussion for stabilization time of carbon steel in atmospheric corrosion

NASA Astrophysics Data System (ADS)

Zhang, Zong-kai; Ma, Xiao-bing; Cai, Yi-kun

2017-09-01

Stabilization time is an important parameter in long-term prediction of carbon steel corrosion in atmosphere. The range of the stabilization time of carbon steel in atmospheric corrosion has been published in many scientific literatures. However, the results may not precise because engineering experiences is dominant. This paper deals with the recalculation of stabilization time based on ISO CORRAG program, and analyzes the results and makes a comparison to the data mentioned above. In addition, a new thinking to obtain stabilization time will be proposed.

Corrosion of 316 stainless steel in high temperature molten Li2BeF4 (FLiBe) salt

NASA Astrophysics Data System (ADS)

Zheng, Guiqiu; Kelleher, Brian; Cao, Guoping; Anderson, Mark; Allen, Todd; Sridharan, Kumar

2015-06-01

In support of structural material development for the fluoride-salt-cooled high-temperature reactor (FHR), corrosion tests of 316 stainless steel were performed in the potential primary coolant, molten Li2BeF4 (FLiBe) at 700 °C for an exposure duration up to 3000 h. Tests were performed in both 316 stainless steel and graphite capsules. Corrosion in both capsule materials occurred by the dissolution of chromium from the stainless steel into the salt which led to the depletion of chromium predominantly along the grain boundaries of the test samples. The samples tested in graphite capsules showed a factor of two greater depth of corrosion attack as measured in terms of chromium depletion, compared to those tested in 316 stainless steel capsules. The samples tested in graphite capsules showed the formation of Cr7C3 particulate phases throughout the depth of the corrosion layer. Samples tested in both types of capsule materials showed the formation of MoSi2 phase due to increased activity of Mo and Si as a result of Cr depletion, and furthermore corrosion promoted the formation of a α-ferrite phase in the near-surface regions of the 316 stainless steel. Based on the corrosion tests, the corrosion attack depth in FLiBe salt was predicted as 17.1 μm/year and 31.2 μm/year for 316 stainless steel tested in 316 stainless steel and in graphite capsules respectively. It is in an acceptable range compared to the Hastelloy-N corrosion in the Molten Salt Reactor Experiment (MSRE) fuel salt.

Corrosion control of carbon steel using inhibitor of banana peel extract in acid diluted solutions

NASA Astrophysics Data System (ADS)

Komalasari; Utami, S. P.; Fermi, M. I.; Aziz, Y.; Irianti, R. S.

2018-04-01

Issues of corrosion happened in pipes, it was used as fluid transportation in the chemical industry. Corrosion cannot be preventing, however it could be controlled or blocked. Inhibitor addition is one of the method to control the corrosion inside the pipe. Corrosion inhibitors consisted of inorganic and organic compound inhibitors. Organic inhibitor is composed from synthetic and natural material. This study focused to evaluate the inhibition’s efficiency from banana peel to carbon steel in different concentration of inhibitor and immersing time in acid solution variation. The research employed inhibitor concentration of 0 gram/liter, 2 gram/liter, 4 gram/liter and 6 gram/liter, immersed time of carbon steel for 2, 4, 6, 8 and 10 hours. It was immersed in chloride acid solution of 0.5 M and 1.5 M. Carbon Steel AISI 4041 was used as specimen steel. Results were analyzed using corrosion rate evaluation for each specimens and inhibitor efficiencies determination. It was found that the specimen without inhibitor yielded fast corrosion rate in long immersing time and high concentration of HCl. However, the specimens with inhibitor gave lowest corrosion rate which was 78.59% for 6 gram/litre and 10 hours in 0.5 M HCl.

Effect of cloric acid concentration on corrosion behavior of Ni/Cr coated on carbon steel

NASA Astrophysics Data System (ADS)

Desiati, Resetiana Dwi; Sugiarti, Eni; Thosin, K. A. Zaini

2018-05-01

Corrosion is one of the causes of metal degradation. Carbon steel (Fe) is easy to corrode in the extreme environment. Coating on carbon steel is required to improve corrosion resistance owing to protection or hindrance to extreme environmental conditions. In this present work, carbon steel was coated by electroplating techniques for nickel and pack cementation for chrome. The corrosion rate test was performed by Weight Loss method on FeNiCr, FeNi, FeCr and uncoated Fe as comparator which was dyed in 37% HCl and 25% HCl which had previously been measured dimension and mass. The immersion test result of FeNiCr and FeNi specimen were better than FeCr and uncoated Fe in terms of increasing corrosion resistance. The corrosion rate for 56 hours in 37% HCl for FeNiCr was 1.592 mm/y and FeNi was 3.208 mm/y, FeCr only lasted within 32 hours with corrosion rate was 6.494 mm/y. Surface of the sample after the corrosion test there was pitting, crevice corrosion and alloy cracking caused by chloride. The higher the concentration of HCl the faster the corrosion rate.

Microbiological corrosion of ASTM SA105 carbon steel pipe for industrial fire water usage

NASA Astrophysics Data System (ADS)

Chidambaram, S.; Ashok, K.; Karthik, V.; Venkatakrishnan, P. G.

2018-02-01

The large number of metallic systems developed for last few decades against both general uniform corrosion and localized corrosion. Among all microbiological induced corrosion (MIC) is attractive, multidisciplinary and complex in nature. Many chemical processing industries utilizes fresh water for fire service to nullify major/minor fire. One such fire water service line pipe attacked by micro-organisms leads to leakage which is industrially important from safety point of view. Also large numbers of leakage reported in similar fire water service of nearby food processing plant, paper & pulp plant, steel plant, electricity board etc…In present investigation one such industrial fire water service line failure analysis of carbon steel line pipe was analyzed to determine the cause of failure. The water sample subjected to various chemical and bacterial analyses. Turbidity, pH, calcium hardness, free chlorine, oxidation reduction potential, fungi, yeasts, sulphide reducing bacteria (SRB) and total bacteria (TB) were measured on water sample analysis. The corrosion rate was measured on steel samples and corrosion coupon measurements were installed in fire water for validating non flow assisted localized corrosion. The sulphide reducing bacteria (SRB) presents in fire water causes a localized micro biological corrosion attack of line pipe.

77 FR 25141 - Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea: Extension of Time...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-27

... DEPARTMENT OF COMMERCE International Trade Administration [A-428-815, A-580-816] Corrosion...) orders on corrosion-resistant carbon steel flat products (CORE) from Germany and South Korea (Korea..., regarding ``Sunset Reviews of the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel Flat Products...

An evaluation of carbon steel corrosion under stagnant seawater conditions.

PubMed

Lee, Jason S; Ray, Richard I; Lemieux, Edward J; Falster, Alexander U; Little, Brenda J

2004-01-01

Corrosion of 1020 carbon steel coupons in natural seawater over a 1-year period was more aggressive under strictly anaerobic stagnant conditions than under aerobic stagnant conditions as measured by weight loss and instantaneous corrosion rate (polarization resistance). Under oxygenated conditions, a two-tiered oxide layer of lepidocrocite/goethite formed. The inner layer was extremely tenacious and resistant to acid cleaning. Under anaerobic conditions, the corrosion product was initially a non-tenacious sulphur-rich corrosion product, mackinawite, with enmeshed bacteria. As more sulphide was produced the mackinawite was transformed to pyrrhotite. In both aerobic and anaerobic exposures, corrosion was more aggressive on horizontally oriented coupons compared to vertically oriented samples.

Biocompatibly Coated 304 Stainless Steel as Superior Corrosion-Resistant Implant Material to 316L Steel

NASA Astrophysics Data System (ADS)

Paul, Subir; Mandal, Chandranath

2013-10-01

Surface treatments of 304 stainless steel by electro-coating and passivating in few inorganic electrolytes were found to be very effective in drastically reducing the corrosion rate of the material in stimulated body fluid (SBF) by several orders in comparison to that of 316L steel, presently being used for orthopedic implants. Polarization studies of electrodeposited hydroxyl apatite coating on 304 steel showed remarkably improved corrosion current. Cyclic polarization of the material in SBF reflected the broadened passivity region, much lower passive current, and narrower hysteresis loops. Similar effects were also found through the formation of inorganic coatings by passivation in NaF, CaNO3, and calcium phosphate buffer solutions. Surface characterization by XRD showed the peaks of the respective coating crystals. The morphology of the coatings studied by SEM showed a flake-type structure for hydroxyapatite coating and fine spherical-subspherical particles for other coatings.

Microstructure Characterization and Corrosion Resistance Behavior of New Cobalt-Free Maraging Steel Produced Through ESR Techniques

NASA Astrophysics Data System (ADS)

Seikh, Asiful H.; Halfa, Hossam; Baig, Muneer; Khan, Sohail M. A.

2017-04-01

In this study, two different grades (M23 and M29) of cobalt-free low nickel maraging steel have been produced through electroslag remelting (ESR) process. The corrosion resistance of these ESR steels was investigated in 1 M H2SO4 solution using linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) techniques. The experiments were performed for different immersion time and solution temperature. To evaluate the corrosion resistance of the ESR steels, some significant characterization parameters from LPP and EIS curves were analyzed and compared with that of conventional C250 maraging steel. Irrespective of measurement techniques used, the results show that the corrosion resistance of the ESR steels was higher than the C250 steel. The microstructure of ESR steels was composed of uniform and well-distributed martensite accompanied with little amount of retained austenite in comparison with C250 steel.

Use of Carbon Steel for Construction of Post-combustion CO 2 Capture Facilities: A Pilot-Scale Corrosion Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei; Landon, James; Irvin, Bradley

Corrosion studies were carried out on metal coated and noncoated carbon steel as well as stainless steel in a pilot-scale post-combustion CO 2 capture process. Aqueous 30 wt % monoethanolamine (MEA) solvent was used without any chemical additive for antioxidation to examine a worst-case scenario where corrosion is not mitigated. The corrosion rate of all carbon steels was almost zero in the absorber column and CO 2 lean amine piping except for Ni-coated carbon steel (<1.8 mm/yr). Ni 2Al 3/Al 2O 3 precoated carbon steels showed initial protection but lost their integrity in the stripping column and CO 2 richmore » amine piping, and severe corrosion was eventually observed for all carbon steels at these two locations. Stainless steel was found to be stable and corrosion resistant in all of the sampling locations throughout the experiment. This study provides an initial framework for the use of carbon steel as a potential construction material for process units with relatively mild operating conditions (temperature less than 80 °C), such as the absorber and CO 2 lean amine piping of a post-combustion CO 2 capture process. As a result, it also warrants further investigation of using carbon steel with more effective corrosion mitigation strategies for process units where harsh environments are expected (such as temperatures greater than 100 °C).« less

Use of Carbon Steel for Construction of Post-combustion CO 2 Capture Facilities: A Pilot-Scale Corrosion Study

DOE PAGES

Li, Wei; Landon, James; Irvin, Bradley; ...

2017-04-13

Corrosion studies were carried out on metal coated and noncoated carbon steel as well as stainless steel in a pilot-scale post-combustion CO 2 capture process. Aqueous 30 wt % monoethanolamine (MEA) solvent was used without any chemical additive for antioxidation to examine a worst-case scenario where corrosion is not mitigated. The corrosion rate of all carbon steels was almost zero in the absorber column and CO 2 lean amine piping except for Ni-coated carbon steel (<1.8 mm/yr). Ni 2Al 3/Al 2O 3 precoated carbon steels showed initial protection but lost their integrity in the stripping column and CO 2 richmore » amine piping, and severe corrosion was eventually observed for all carbon steels at these two locations. Stainless steel was found to be stable and corrosion resistant in all of the sampling locations throughout the experiment. This study provides an initial framework for the use of carbon steel as a potential construction material for process units with relatively mild operating conditions (temperature less than 80 °C), such as the absorber and CO 2 lean amine piping of a post-combustion CO 2 capture process. As a result, it also warrants further investigation of using carbon steel with more effective corrosion mitigation strategies for process units where harsh environments are expected (such as temperatures greater than 100 °C).« less

76 FR 3613 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-20

... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea) for the period of review (POR) January 1, 2008, through December 31, 2008. See Corrosion-Resistant Carbon Steel Flat...

78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

.... Scope of the Order Products covered by this order are certain corrosion-resistant carbon steel flat... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... countervailing duty (CVD) order on corrosion-resistant carbon steel flat products from the Republic of Korea for...

Enhanced corrosion resistance of strontium hydroxyapatite coating on electron beam treated surgical grade stainless steel

NASA Astrophysics Data System (ADS)

Gopi, D.; Rajeswari, D.; Ramya, S.; Sekar, M.; R, Pramod; Dwivedi, Jishnu; Kavitha, L.; Ramaseshan, R.

2013-12-01

The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.

Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions

USDA-ARS?s Scientific Manuscript database

Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

Corrosion fatigue in nitrocarburized quenched and tempered steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karim Khani, M.; Dengel, D.

1996-05-01

In order to investigate the fatigue strength and fracture mechanism of salt bath nitrocarburized steels, specimens of the steels SAE 4135 and SAE 4140, in a quenched and tempered state, and additionally in a salt bath nitrocarburized and oxidizing cooled state as well as in a polished (after the oxidizing cooling) and renewed oxidized state, were subjected to comparative rotating bending fatigue tests in inert oil and 5 pct NaCl solution. In addition, some of the quenched and tempered specimens of SAE 4135 material were provided with an approximately 50-{mu}m-thick electroless Ni-P layer, in order to compare corrosion fatigue behaviormore » between the Ni-P layer and the nitride layers. Long-life corrosion fatigue tests of SAE 4135 material were carried out under small stresses in the long-life range up to 10{sup 8} cycles with a test frequency of 100 Hz. Fatigue tests of SAE 4140 material were carried out in the range of finite life (low-cycle range) with a test frequency of 13 Hz. The results show that the 5 pct NaCl environment drastically reduced fatigue life, but nitrocarburizing plus oxidation treatment was found to improve the corrosion fatigue life over that of untreated and Ni-P coated specimens. The role of inclusions in initiating fatigue cracks was investigated. It was found that under corrosion fatigue conditions, the fatigue cracks started at cavities along the interfaces of MnS inclusions and matrix in the case of quenched and tempered specimens. The nitrocarburized specimens, however, showed a superposition of pitting corrosion and corrosion fatigue in which pores and nonmetallic inclusions in the compound layer play a predominant role concerning the formation of pits in the substrate.« less

Galvanic corrosion of ferritic stainless steels used for dental magnetic attachments in contact with an iron-platinum magnet.

PubMed

Nakamura, Keisuke; Takada, Yukyo; Yoda, Masanobu; Kimura, Kohei; Okuno, Osamu

2008-03-01

This study was an examination of the galvanic corrosion of ferritic stainless steels, namely SUS 444, SUS XM27, and SUS 447J1, in contact with a Fe-Pt magnet. The surface area ratio of each stainless steel to the Fe-Pt magnet was set at 1/1 or 1/10. Galvanic corrosion between the stainless steels and the magnet was evaluated by the amount of released ions and the electrochemical properties in 0.9% NaCl solution. Although each stainless steel showed sufficient corrosion resistance for clinical use, the amount of ions released from each tended to increase when the stainless steel was in contact with the magnet. When the surface area ratio was reduced to 1/10, the amount of Fe ions released from the stainless steels increased significantly more than when there was no contact. Since contact with the magnet which possessed an extremely noble potential created a very corrosive environment for the stainless steels, 447J1 was thus the recommended choice against a corrosion exposure as such.

Neutrophilic iron-oxidizing "zetaproteobacteria" and mild steel corrosion in nearshore marine environments.

PubMed

McBeth, Joyce M; Little, Brenda J; Ray, Richard I; Farrar, Katherine M; Emerson, David

2011-02-01

Microbiologically influenced corrosion (MIC) of mild steel in seawater is an expensive and enduring problem. Little attention has been paid to the role of neutrophilic, lithotrophic, iron-oxidizing bacteria (FeOB) in MIC. The goal of this study was to determine if marine FeOB related to Mariprofundus are involved in this process. To examine this, field incubations and laboratory microcosm experiments were conducted. Mild steel samples incubated in nearshore environments were colonized by marine FeOB, as evidenced by the presence of helical iron-encrusted stalks diagnostic of the FeOB Mariprofundus ferrooxydans, a member of the candidate class "Zetaproteobacteria." Furthermore, Mariprofundus-like cells were enriched from MIC biofilms. The presence of Zetaproteobacteria was confirmed using a Zetaproteobacteria-specific small-subunit (SSU) rRNA gene primer set to amplify sequences related to M. ferrooxydans from both enrichments and in situ samples of MIC biofilms. Temporal in situ incubation studies showed a qualitative increase in stalk distribution on mild steel, suggesting progressive colonization by stalk-forming FeOB. We also isolated a novel FeOB, designated Mariprofundus sp. strain GSB2, from an iron oxide mat in a salt marsh. Strain GSB2 enhanced uniform corrosion from mild steel in laboratory microcosm experiments conducted over 4 days. Iron concentrations (including precipitates) in the medium were used as a measure of corrosion. The corrosion in biotic samples (7.4 ± 0.1 mM) was significantly higher than that in abiotic controls (5.0 ± 0.1 mM). These results have important implications for the role of FeOB in corrosion of steel in nearshore and estuarine environments. In addition, this work shows that the global distribution of Zetaproteobacteria is far greater than previously thought.

77 FR 31877 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-350 and 731-TA-616 and 618 (Third Review)] Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five-Year Reviews... corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion...

Performance evaluation of corrosion inhibitors and galvanized steel in concrete exposure specimens.

DOT National Transportation Integrated Search

1999-01-01

Corrosion inhibitor admixtures (CIA) and galvanized reinforcing steel (GS) are used for the corrosion protection for reinforced concrete bridges. The results of a 3.5-year evaluation of exposure specimens containing CIA from three different manufactu...

The Effect of Cathodic Protection on Stress Corrosion Cracking of High-Strength Pipeline Steels, #350

DOT National Transportation Integrated Search

2009-12-02

The objective of this study was to establish the effect of cathodic protection (CP) to produce hydrogen that can cause cracking and in-service failures of high-strength pipeline steels, from X-70 to X-120, and to establish the effectiveness of cathod...

Study of Rust Effect on the Corrosion Behavior of Reinforcement Steel Using Impedance Spectroscopy

NASA Astrophysics Data System (ADS)

Bensabra, Hakim; Azzouz, Noureddine

2013-12-01

Most studies on corrosion of steel reinforcement in concrete are conducted on steel samples with polished surface (free of all oxides) in order to reproduce the same experimental conditions. However, before embedding in concrete, the steel bars are often covered with natural oxides (rust), which are formed during exposure to the atmosphere. The presence of this rust may affect the electrochemical behavior of steel rebar in concrete. In order to understand the effect of rust on the corrosion behavior of reinforcement steel, potentiodynamic and electrochemical impedance spectroscopy (EIS) tests were carried out in a simulated concrete pore solution using steel samples with two different surface conditions: polished and rusted samples. The obtained results have shown that the presence of rust on the steel bar has a negative effect on its corrosion behavior, with or without the presence of chlorides. This detrimental effect can be explained by the fact that the rust provokes a decrease of the electrolyte resistance at the metal-concrete interface and reduces the repassivating ability. In addition, the rust layer acts as a barrier against the hydroxyl ion diffusion, which prevents the realkalinization phenomenon.

Enhancement of corrosion resistance of carbon steel by Dioscorea Hispida starch in NaCl

NASA Astrophysics Data System (ADS)

Zulhusni, M. D. M.; Othman, N. K.; Lazim, Azwan Mat

2015-09-01

Starch is a one of the most abundant natural product in the world and has the potential as corrosion inhibitor replacing harmful synthetic chemical based corrosion inhibitor. This research was aimed to examines the potential of starch extracted from local Malaysian wild yam (Dioscorea hispida), as corrosion inhibitor to carbon steel in NaCl media replicating sea water. By using gravimetric test and analysis, in which the carbon steel specimens were immersed in NaCl media for 24, 48 and 60 hours with the starch as corrosion inhibitor. the corrosion rate (mmpy) and inhibition efficiencies (%) was calculated. The results obtained showed decrease in corrosion rate as higher concentration of starch was employed. The inhibition efficiencies also shows an increasing manner up to 95.97 % as the concentration of the inhibitor increased.

Corrosion fatigue in nitrocarburized quenched and tempered steels

NASA Astrophysics Data System (ADS)

Khani, M. Karim; Dengel, D.

1996-05-01

In order to investigate the fatigue strength and fracture mechanism of salt bath nitrocarburized steels, specimens of the steels SAE 4135 and SAE 4140, in a quenched and tempered state, and additionally in a salt bath nitrocarburized and oxidizing cooled state as well as in a polished (after the oxidizing cooling) and renewed oxidized state, were subjected to comparative rotating bending fatigue tests in inert oil and 5 pct NaCl solution. In addition, some of the quenched and tempered specimens of SAE 4135 material were provided with an approximately 50-μm-thick electroless Ni-P layer, in order to compare corrosion fatigue behavior between the Ni-P layer and the nitride layers. Long-life corrosion fatigue tests of SAE 4135 material were carried out under small stresses in the long-life range up to 108 cycles with a test frequency of 100 Hz. Fatigue tests of SAE 4140 material were carried out in the range of finite life (low-cycle range) with a test frequency of 13 Hz. The results show that the 5 pct NaCl environment drastically reduced fatigue life, but nitrocarburizing plus oxidation treatment was found to improve the corrosion fatigue life over that of untreated and Ni-P coated specimens. The beneficial effect of nitrocarburizing followed by oxidation treatment on cor-rosion fatigue life results from the protection rendered by the compound layer by means of a well-sealed oxide layer, whereby the pores present in the compound layer fill up with oxides. The role of inclusions in initiating fatigue cracks was investigated. It was found that under corrosion fatigue conditions, the fatigue cracks started at cavities along the interfaces of MnS inclusions and matrix in the case of quenched and tempered specimens. The nitrocarburized specimens, however, showed a superposition of pitting corrosion and corrosion fatigue in which pores and nonmetallic inclusions in the compound layer play a predominant role concerning the formation of pits in the substrate.

Research and development of weathering resistant bridge steel of Shougang

NASA Astrophysics Data System (ADS)

Yang, Yongda; Wang, Yanfeng; Huang, Leqing; Di, Guobiao; Ma, Changwen; Ma, Qingshen

2017-09-01

To introduce the composition design and mechanical properties and microstructure of the weathering bridge steel which would be used for bridge of Guanting reservoir. We adopt cyclic immersion corrosion test to study corrosion resistance difference of weathering bridge steel and common bridge steel. At the same corrosion time, the weight loss and corrosion rate of weathering bridge steel are lower than the common bridge steel's. Testing phase composition of rust layer by X-ray diffraction, two kinds of test steel's rust layer is mainly composed of Goethite and Fe3O4 and Fe2O3. At the same corrosion time, the percentage composition of goethite in rust layer of weathering bridge steel are significantly higher than common bridge steel's, the higher goethite content is, the compacter rust layer structure is. The compact rust layer would prevent the water and air passing the rust layer, and then preventing the further corrosion reaction, improving the corrosion resistance performance of weathering bridge steel.

Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars

PubMed Central

Tang, Fujian; Chen, Genda; Brow, Richard K.; Koenigstein, Michael L.

2014-01-01

The protective performance of a sand particle-modified enamel coating on reinforcing steel bars was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS). Seven percentages of sand particles by weight were investigated: 0%, 5%, 10%, 20%, 30%, 50% and 70%. The phase composition of the enamel coating and sand particles were determined with the X-ray diffraction (XRD) technique. The surface and cross-sectional morphologies of the sand particle-modified enamel coating were characterized using scanning electron microscopy (SEM). XRD tests revealed three phases of sand particles: SiO2, CaCO3 and MgCO3. SEM images demonstrated that the enamel coating wetted well with the sand particles. However, a weak enamel coating zone was formed around the sand particles due to concentrated air bubbles, leading to micro-cracks as hydrogen gas pressure builds up and exceeds the tensile strength of the weak zone. As a result, the addition of sand particles into the enamel coating reduced both the coating and corrosion resistances. PMID:28788203

Corrosion of austenitic steels and their components in vanadium-containing chloride melts

NASA Astrophysics Data System (ADS)

Abramov, A. V.; Polovov, I. B.; Rebrin, O. I.; Lisienko, D. G.

2014-08-01

The corrosion of austenitic 12Kh18N10T, 10Kh17N13M2T, and 03Kh17N14M3 steels and their components (Cr, Fe, Ni, Mo) in NaCl-KCl-VCl2 melts with 5 wt % V at 750°C is studied. The rates and mechanisms of corrosion of the materials under these conditions are determined. The processes that occur during contact of the metals and steels with vanadium-containing chloride electrolytes are investigated.

Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings

PubMed Central

Jones, John Eric; Chen, Meng; Yu, Qingsong

2015-01-01

To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O-and N-contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electro-chemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. PMID:24500866

Image analysis of corrosion pit initiation on ASTM type A240 stainless steel and ASTM type A 1008 carbon steel

NASA Astrophysics Data System (ADS)

Nine, H. M. Zulker

The adversity of metallic corrosion is of growing concern to industrial engineers and scientists. Corrosion attacks metal surface and causes structural as well as direct and indirect economic losses. Multiple corrosion monitoring tools are available although those are time-consuming and costly. Due to the availability of image capturing devices in today's world, image based corrosion control technique is a unique innovation. By setting up stainless steel SS 304 and low carbon steel QD 1008 panels in distilled water, half-saturated sodium chloride and saturated sodium chloride solutions and subsequent RGB image analysis in Matlab, in this research, a simple and cost-effective corrosion measurement tool has identified and investigated. Additionally, the open circuit potential and electrochemical impedance spectroscopy results have been compared with RGB analysis to gratify the corrosion. Additionally, to understand the importance of ambiguity in crisis communication, the communication process between Union Carbide and Indian Government regarding the Bhopal incident in 1984 was analyzed.

No corrosion of 304 stainless steel implant after 40 years of service.

PubMed

Blackwood, D J; Pereira, B P

2004-07-01

When exposed to 0.9% NaCl type 304 stainless steel undergoes severe pitting corrosion within a matter of days. However, a Sherman plate fabricated from type 304 stainless steel remained inside a patient's arm for almost 40 years without any visible indications of corrosion. Given the previous understanding of the pathological environments this was considered quite remarkable. It is proposed that the low dissolved oxygen levels found in human-body fluids makes the long-term in vivo environment much more benign than would be anticipated from in vitro experiments. Furthermore, it is proposed that previous cases of localized pitting corrosion on stainless steel implants most likely arose due to the development of short-term aggressive conditions due to pathological changes in the surrounding tissue as a result of the trauma of the implant procedure. In the present case the Sherman plate was sufficiently small that the surrounding tissue was not aggravated sufficiently to lead to the development of such an environment aggressive. The conclusion that surgical implants are at most risk during the first few weeks of service implies that short-term corrosion protection methods, such as coatings, may be more effective than previously thought.

Influence of Heat Treatment on the Microstructure and Corrosion Resistance of 13 Wt Pct Cr-Type Martensitic Stainless Steel

NASA Astrophysics Data System (ADS)

Lu, Si-Yuan; Yao, Ke-Fu; Chen, Yun-Bo; Wang, Miao-Hui; Ge, Xue-Yuan

2015-12-01

The effect of heat treatment on the microstructure and the electrochemical properties of a typical corrosion-resistant plastic mold steel in Cl--containing solution were studied in this research. Through X-ray diffraction patterns, SEM and TEM analysis, it was found that the sequence of the precipitates in the steels tempered at 573 K, 773 K, and 923 K (300 °C, 500 °C, and 650 °C) was θ-M3C carbides, nano-sized Cr-rich M23C6 carbides, and micro/submicron-sized Cr-rich M23C6 carbides, respectively. The results of the electrochemical experiments showed that the pitting potential of the as-quenched martensitic stainless steels increased with the austenitizing temperature. However, the corrosion resistance of the steels would decreased after tempering, especially when tempered at 773 K (500 °C), no passivation regime could be found in the polarization curve of the MSSs and no effective passive film could be formed on the steels in Cl--containing environments. The present results suggested that the temperature around 773 K (500 °C) should be avoided for tempering process of MSS used as plastic molds.

Stress Corrosion Cracking of an Austenitic Stainless Steel in Nitrite-Containing Chloride Solutions

PubMed Central

Singh Raman, R. K.; Siew, Wai Hoong

2014-01-01

This article describes the susceptibility of 316L stainless steel to stress corrosion cracking (SCC) in a nitrite-containing chloride solution. Slow strain rate testing (SSRT) in 30 wt. % MgCl2 solution established SCC susceptibility, as evidenced by post-SSRT fractography. Addition of nitrite to the chloride solution, which is reported to have inhibitive influence on corrosion of stainless steels, was found to increase SCC susceptibility. The susceptibility was also found to increase with nitrite concentration. This behaviour is explained on the basis of the passivation and pitting characteristics of 316L steel in chloride solution. PMID:28788276

Controlled ferrite content improves weldability of corrosion-resistant steel

NASA Technical Reports Server (NTRS)

Malin, C. O.

1967-01-01

Corrosion-resistant steel that adds restrictions on chemical composition to ensure sufficient ferrite content decreases the tendency of CRES to develop cracks during welding. The equations restricting composition are based on the Schaeffler constitution diagram.

Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

NASA Technical Reports Server (NTRS)

Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

2002-01-01

The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

Evaluation of mechanical and corrosion properties of MMFX reinforcing steel for concrete

DOT National Transportation Integrated Search

2004-01-01

The corrosion performance of MMFX and conventional reinforcing steels is compared based on macrocell and bench-scale tests. The conventional steel includes epoxy-coated and uncoated bars. Macrocell tests are conducted on bare bars and bars symmetrica...

Effects of the Treating Time on Microstructure and Erosion Corrosion Behavior of Salt-Bath-Nitrided 17-4PH Stainless Steel

NASA Astrophysics Data System (ADS)

Wang, Jun; Lin, Yuanhua; Li, Mingxing; Fan, Hongyuan; Zeng, Dezhi; Xiong, Ji

2013-08-01

The effects of salt-bath nitriding time on the microstructure, microhardness, and erosion-corrosion behavior of nitrided 17-4PH stainless steel at 703 K (430 °C) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and erosion-corrosion testing. The experimental results revealed that the microstructure and phase constituents of the nitrided surface alloy are highly process condition dependent. When 17-4PH stainless steel was subjected to complex salt-bathing nitriding, the main phase of the nitrided layer was expanded martensite ( α`), expanded austenite (S), CrN, Fe4N, and Fe2N. The thickness of nitrided layers increased with the treating time. The salt-bath nitriding improves effectively the surface hardness. The maximum values measured from the treated surface are observed to be 1100 HV0.1 for 40 hours approximately, which is about 3.5 times as hard as the untreated material (309 HV0.1). Low-temperature nitriding can improve the erosion-corrosion resistance against two-phase flow. The sample nitrided for 4 hours has the best corrosion resistance.

Influence of ultraviolet light irradiation on the corrosion behavior of carbon steel AISI 1015

NASA Astrophysics Data System (ADS)

Riazi, H. R.; Danaee, I.; Peykari, M.

2013-03-01

Corrosion of carbon steel in sodium chloride solution was studied under ultraviolet illumination using weight loss, polarization, electrochemical impedance spectroscopy and current transient tests. The polarization test revealed an increase in the corrosion current density observed under UV illumination. The impedance spectroscopy indicated that the charge transfer resistance of the system was decreased by irradiation of UV light on a carbon steel electrode. The weight loss of carbon steel in solution increased under UV light, which confirms the results obtained from electrochemical measurements. We propose that the main effect of UV irradiation is on the oxide film, which forms on the surface. Thus, in presence of UV, the conductivity of oxide film might increase and lead to higher metal dissolution and corrosion rate.

Corrosion Prevention of Steel Reinforcement in 7.5% NaCl Solution using Pure Magnesium Anode

NASA Astrophysics Data System (ADS)

Iyer Murthy, Yogesh; Gandhi, Sumit; Kumar, Abhishek

2018-03-01

The current work investigates the performance of pure Magnesium on corrosion prevention of steel reinforcements by way of sacrificial anoding. Two set of six steel reinforcements were tested for half-cell potential, weight loss, anode efficiency and tensile strength for each of the sacrificial anodes in a high chloride atmosphere of 7.5% NaCl in tap water. Significant reduction in weight of anode was observed during the initial 12 days. The reduction in weight of steel reinforcements tied with anodes was found to be negligible, while that of reinforcements without anodes was significantly higher. Five distinct zones of corrosion were observed during the test. The tensile strength of steel cathodically protected by Mg alloy anodes was found less affected. It could be concluded that pure Mg anode provides an effective way of corrosion mitigation.

Corrosion of stainless steel sternal wire after long-term implantation.

PubMed

Tomizawa, Yasuko; Hanawa, Takao; Kuroda, Daisuke; Nishida, Hiroshi; Endo, Masahiro

2006-01-01

A variety of metallic components have been used in medical devices where lifelong durability and physical strength are demanded. To investigate the in vivo changes of implanted metallic medical devices in humans, stainless steel sternal wires removed from patients were evaluated. Stainless steel (316L) sternal wires removed from four patients after 10, 13, 22, and 30 years of implantation were evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Macroscopically, the removed specimens maintained their metallic luster and color. Under SEM, small holes were observed sporadically at 10 years and they tended to connect in the drawing direction. The longer the implanted duration, the more numerous and deeper were the crevices observed. By EDS, sulfur, phosphorus, and calcium were identified in all areas at 10 years, in addition to the component elements of stainless steel, comprising iron, chromium, nickel, and manganese. Corrosion products observed at 30 years were identified as calcium phosphate. In conclusion, stainless steel sternal wires develop corroded pores that grow larger and deeper with time after implantation; however, the pores remain shallow even after decades of implantation and they may not be a cause of mechanical failure. An amount of metal ions equivalent to the corroded volume must have been released into the human body, but the effect of these metal ions on the body is not apparent.

Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

DOE PAGES

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan; ...

2015-08-05

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less

Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less

Corrosion of carbon steel by bacteria from North Sea offshore seawater injection systems: laboratory investigation.

PubMed

Stipanicev, Marko; Turcu, Florin; Esnault, Loïc; Rosas, Omar; Basseguy, Régine; Sztyler, Magdalena; Beech, Iwona B

2014-06-01

Influence of sulfidogenic bacteria, from a North Sea seawater injection system, on the corrosion of S235JR carbon steel was studied in a flow bioreactor; operating anaerobically for 100days with either inoculated or filtrated seawater. Deposits formed on steel placed in reactors contained magnesium and calcium minerals plus iron sulfide. The dominant biofilm-forming organism was an anaerobic bacterium, genus Caminicella, known to produce hydrogen sulfide and carbon dioxide. Open Circuit Potentials (OCP) of steel in the reactors was, for nearly the entire test duration, in the range -800corrosion rate, expressed as 1/(Rp/Ω), was lower in the inoculated seawater though they varied significantly on both reactors. Initial and final corrosion rates were virtually identical, namely initial 1/(Rp/Ω)=2×10(-6)±5×10(-7) and final 1/(Rp/Ω)=1.1×10(-5)±2.5×10(-6). Measured data, including electrochemical noise transients and statistical parameters (0.0545), suggested pitting on steel samples within the inoculated environment. However, the actual degree of corrosion could neither be directly correlated with the electrochemical data and nor with the steel corrosion in the filtrated seawater environment. Further laboratory tests are thought to clarify the noticed apparent discrepancies. © 2013.

Effect of Different Thermomechanical Processes on the Microstructure, Texture, and Mechanical Properties of API 5L X70 Steel

NASA Astrophysics Data System (ADS)

Masoumi, Mohammad; Echeverri, Edwan Anderson Ariza; Silva, Cleiton Carvalho; Béreš, Miloslav; de Abreu, Hamilton Ferreira Gomes

2018-03-01

A commercial API 5L X70 steel plate was subjected to different thermomechanical processes to propose a novel thermomechanical rolling path to achieve improved mechanical properties. Scanning electron microscopy, electron backscatter diffraction, and x-ray texture analysis were employed for microstructural characterization. The results showed that strain-free recrystallized {001} ferrite grains that developed at higher rolling temperature could not meet the American Petroleum Institute (API) requirements. Also, refined and work-hardened grains that have formed in the intercritical region with high stored energy do not provide suitable tensile properties. However, fine martensite-austenite constituents dispersed in ferrite matrix with grains having predominantly {111} and {110} orientations parallel to the normal direction that developed under isothermal rolling at 850 °C provided an outstanding combination of tensile strength and ductility.

Influence of nitrogen in the shielding gas on corrosion resistance of duplex stainless steel welds

NASA Astrophysics Data System (ADS)

Bhatt, R. B.; Kamat, H. S.; Ghosal, S. K.; de, P. K.

1999-10-01

The influence of nitrogen in shielding gas on the corrosion resistance of welds of a duplex stainless steel (grade U-50), obtained by gas tungsten arc (GTA) with filler wire, autogenous GTA (bead-on-plate), electron beam welding (EBW), and microplasma techniques, has been evaluated in chloride solutions at 30 °C. Pitting attack has been observed in GTA, electron beam welding, and microplasma welds when welding has been carried out using pure argon as the shielding gas. Gas tungsten arc welding with 5 to 10% nitrogen and 90 to 95% argon, as the shielding gas, has been found to result in an improved pitting corrosion resistance of the weldments of this steel. However, the resistance to pitting of autogenous welds (bead-on-plate) obtained in pure argon as the shielding gas has been observed to remain unaffected. Microscopic examination, electron probe microanalysis (EPMA), and x-ray diffraction studies have revealed that the presence of nitrogen in the shielding gas in the GTA welds not only modifies the microstructure and the austenite to ferrite ratio but also results in a nearly uniform distribution of the various alloying elements, for example, chromium, nickel, and molybdenum among the constitutent phases, which are responsible for improved resistance to pitting corrosion.

Influence of nitrogen in the shielding gas on corrosion resistance of duplex stainless steel welds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, R.B.; Kamat, H.S.; Ghosal, S.K.

1999-10-01

The influence of nitrogen in shielding gas on the corrosion resistance of welds of a duplex stainless steel (grade U-50), obtained by gas tungsten arc (GTA) with filler wire, autogenous GTA (bead-on-plate), electron beam welding (EBW), and microplasma techniques, has been evaluated in chloride solutions at 30 C. Pitting attack has been observed in GTA, electron beam welding, and microplasma welds when welding has been carried out using pure argon as the shielding gas. Gas tungsten arc welding with 5 to 10% nitrogen and 90 to 95% argon, as the shielding gas, has been found to result in an improvedmore » pitting corrosion resistance of the weldments of this steel. However, the resistance of pitting of autogenous welds (bead-on-plate) obtained in pure argon as the shielding gas has been observed to remain unaffected. Microscopic examination, electron probe microanalysis (EPMA), and x-ray diffraction studies have revealed that the presence of nitrogen in the shielding gas in the GTA welds not only modifies the microstructure and the austenite to ferrite ratio but also results in a nearly uniform distribution of the various alloying elements, for example, chromium, nickel, and molybdenum among the constituent phases, which are responsible for improved resistance to pitting corrosion.« less

Effects of cement alkalinity, exposure conditions and steel-concrete interface on the time-to-corrosion and chloride threshold for reinforcing steel in concrete

NASA Astrophysics Data System (ADS)

Nam, Jingak

Effects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH measurement of concrete pore water. Once specimens were fabricated and exposed to a corrosive chloride solution, various experimental techniques were employed to determine time-to-corrosion, chloride threshold, diffusion coefficient and void density along the rebar trace as well as pore water pH. Based upon the resultant data, several findings related to the above parameters have been obtained as summarized below. First, time for the corrosion initiation was longest for G109 concrete specimens with high alkalinity cement (HA). Also, chloride threshold increased with increasing time-to-corrosion and cement alkalinity. Consequently, the HA specimens exhibited the highest chloride threshold compared to low and normal alkalinity ones. Second, high temperature and temperature variations reduced time-to-corrosion of reinforcing steel in concrete since chloride diffusion was accelerated at higher temperature and possibly by temperature variations. The lowest chloride threshold values were found for outdoor exposed specimens suggesting that variation of RH or temperature (or both) facilitated rapid chloride diffusion. Third, an elevated time-to-corrosion and chloride threshold values were found for the wire brushed steel specimens compared to as-received ones. The higher ratio of [OH-]/[Fe n+] on the wire brushed steel surface compared to that of as-received case can be the possible cause because the higher ratio of this parameter enables the formation of a more protective passive film on

Corrosion behaviour of stainless steels in flowing LBE at low and high oxygen concentration

NASA Astrophysics Data System (ADS)

Aiello, A.; Azzati, M.; Benamati, G.; Gessi, A.; Long, B.; Scaddozzo, G.

2004-11-01

The corrosion behaviours of austenitic steel AISI 316L and martensitic steel T91 were investigated in flowing lead-bismuth eutectic (LBE) at 400 °C. The tests were performed in the LECOR and CHEOPE III loops, which stood for the low oxygen concentration and high oxygen concentration in LBE, respectively. The results obtained shows that steels were affected by dissolution at the condition of low oxygen concentration ( C[O 2] = 10 -8-10 -10 wt%) and were oxidized at the condition of high oxygen concentration ( C[O 2] = 10 -5-10 -6 wt%). The oxide layers detected are able to protect the steels from dissolution in LBE. Under the test condition adopted, the austenitic steel behaved more resistant to corrosion induced by LBE than the martensitic steel.

Corrosion study of bare and coated stainless steel

NASA Technical Reports Server (NTRS)

Morrison, J. D.

1972-01-01

A program was conducted at Kennedy Space Center from February 1968 to February 1971 to evaluate the performance of austenitic stainless steel alloys used in fluid systems lines. For several years, there had been numerous failures of stainless steel hardware caused by pitting and stress corrosion cracking. Several alloys were evaluated for effectiveness of certain sacrificial-type protective coverings in preventing corrosion failures. Samples were tested in specially designed racks placed 91 meters (100 yards) above high-tide line at Cape Kennedy. It is concluded that: (1) unprotected tubing samples showed evidence of pitting initiation after 2 weeks; (2) although some alloys develop larger pits than others, it is probable that the actual pitting rate is independent of alloy type; (3) the deepest pitting occurred in the sheltered part of the samples; and (4) zinc-rich coatings and an aluminum-filled coating have afforded sacrificial protection against pitting for at least 28 months. It is believed that a much longer effective coating life can be expected.

Protective Behavior of Poly(m-aminophenol) and Polypyrrole Coatings on Mild Steel

NASA Astrophysics Data System (ADS)

Yahaya, Sabrina M.; Harun, M. K.; Rosmamuhamadani, R.; Bonnia, N. N.; Ratim, S.

2018-01-01

Electrodeposition of polypyrrole (PPy) and poly (m-aminophenol) (PMAP) films on mild steel (MS) substrate was achieved in 0.3M oxalic acid solution and 0.3M NaOH, water:ethanol (70:30) solvent respectively using cyclic voltammetry technique. The morphology of the films constructed was determined by scanning electron microscope (SEM) while energy dispersive X-Ray analyzer (EDX) was used to establish the presence of organic PMAP and PPy film coating and its compositions. The corrosion performance of MS coated with both polymer films were investigated after 0.5 hours immersed in 0.5M NaCl aqueous solution by using polarization curves. It was found that PPy coating provides anodic protection while PMAP coating provides cathodic protection towards corrosion protection of mild steel substrate.

A Galvanic Sensor for Monitoring the Corrosion Condition of the Concrete Reinforcing Steel: Relationship Between the Galvanic and the Corrosion Currents

PubMed Central

Pereira, Elsa Vaz; Figueira, Rita Bacelar; Salta, Maria Manuela Lemos; da Fonseca, Inês Teodora Elias

2009-01-01

This work reports a study carried out on the design and performance of galvanic and polarization resistance sensors to be embedded in concrete systems for permanent monitoring of the corrosion condition of reinforcing steel, aiming to establish a correlation between the galvanic currents, Igal, and the corrosion currents, Icorr, estimated from the polarization resistance, Rp. Sensors have been tested in saturated Ca(OH)2 aqueous solutions, under a variety of conditions, simulating the most important parameters that can accelerate the corrosion of concrete reinforcing steel, such as carbonation, ingress of chloride ions, presence or absence of O2. For all the conditions, the influence of temperature (20 to 55 °C) has also been considered. From this study, it could be concluded that the galvanic currents are sensitive to the various parameters following a trend similar to that of the Rp values. A relationship between the galvanic and the corrosion current densities was obtained and the limiting values of the Igal, indicative of the state condition of the reinforcing steel for the designed sensor, were established. PMID:22291514

Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

NASA Astrophysics Data System (ADS)

Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

2017-04-01

Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

Effects of Ce on Inclusions, Microstructure, Mechanical Properties, and Corrosion Behavior of AISI 202 Stainless Steel

NASA Astrophysics Data System (ADS)

Cai, Guojun; Li, Changsheng

2015-10-01

The sizes and morphologies of nonmetallic inclusions, microhardness, tensile strength, and Charpy impact toughness in AISI 202 stainless steel with different Ce contents were synthetically analyzed by means of SEM, TEM, microhardness tester, and tensile and Charpy impact tests. Effects of Ce addition on the corrosion behavior were investigated in 5 wt.% H2SO4 solution for different periods of time through measuring AC impedance. The EIS measurements indicate that the steels with Ce addition exhibit higher R p values than those without Ce, which illustrates the relative resistance to uniform corrosion is accompanied by an increasing Ce addition. Ce addition to AISI 202 stainless steel improves its uniform corrosion resistance owing to metamorphic inclusions and the improvement of electrode potential in matrix. Upon increasing Ce addition, the indentation morphology of samples transfers from sink-in types to pile-up types, explaining good machinability of steels containing Ce. It is witnessed from the fracture mode that Ce refines the grain size of steels, significantly increasing the strength; in the meantime, its plasticity is improved, thereby solving the contradiction between the strength and the plasticity of steels. It is concluded that AISI 202 stainless steel with 0.016 wt.% Ce addition in the mass fraction has the best mechanical properties and the uniform corrosion resistance.

A study on corrosion resistance of dissimilar welds between Monel 400 and 316L austenitic stainless steel

NASA Astrophysics Data System (ADS)

Mani, Cherish; Karthikeyan, R.; Vincent, S.

2018-04-01

An attempt has been made to study the corrosion resistance of bi-metal weld joints of Monel 400 tube to stainless steel 316 tube by GTAW process. The present research paper contributes to the ongoing research work on the use of Monel400 and 316L austenitic stainless steel in industrial environments. Potentiodynamic method is used to investigate the corrosion behavior of Monel 400 and 316L austenitic stainless steel welded joints. The analysis has been performed on the base metal, heat affected zone and weld zone after post weld heat treatment. Optical microscopy was also performed to correlate the results. The heat affected zone of Monel 400 alloy seems to have the lowest corrosion resistance whereas 316L stainless steel base metal has the highest corrosion resistance.

Long-term corrosion evaluation of stainless steels in Space Shuttle iodinated resin and water

NASA Technical Reports Server (NTRS)

Krohn, Douglas D.

1992-01-01

The effects of stainless steel exposure to iodinated water is a concern in developing the Integrated Water System (IWS) for Space Station Freedom. The IWS has a life requirement of 30 years, but the effects of general and localized corrosion over such a long period have not been determined for the candidate materials. In 1978, Umpqua Research Center immersed stainless steel 316L, 321, and 347 specimens in a solution of deionized water and the Space Shuttle microbial check valve resin. In April 1990, the solution was chemically analyzed to determine the level of corrosion formed, and the surface of each specimen was examined with scanning electron microscopy and metallography to determine the extent of general and pitting corrosion. This examination showed that the attack on the stainless steels was negligible and never penetrated past the first grain boundary layer. Of the three alloys, 316L performed the best; however, all three materials proved to be compatible with an aqueous iodine environment. In addition to the specimens exposed to aqueous iodine, a stainless steel specimen (unspecified alloy) was exposed to moist microbial check valve resin and air for a comparable period. This environment allowed contact of the metal to the resin as well as to the iodine vapor. Since the particular stainless steel alloy was not known, energy dispersive spectroscopy was used to determine that this alloy was stainless steel 301. The intergranular corrosion found on the specimen was limited to the first grain boundary layer.

Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

PubMed

Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

2015-01-01

Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined. Copyright © 2014 Elsevier B.V. All rights reserved.

Study on stainless steel electrode based on dynamic aluminum liquid corrosion mechanism.

PubMed

Hou, Hua; Yang, Ruifeng

2009-01-01

Scanning electrion microscope (SEM) was performed for investigations on the corrosion mechanism of stainless steel electrode in dynamic melting aluminum liquid. Microstructures and composition analysis was made by electron probe analysis (EPA) combined with metallic phase analysis. It can be concluded that the corrosion process is mainly composed of physical corrosion (flowing and scouring corrosion) and chemical corrosion (forming FeAl and Fe2Al5) and the two mechanisms usually exist simultaneously. The corrosion interface thickness is about 10 μm, which is different to usual interface width of hundreds μm in the static melting Al with iron matrix.

Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

NASA Astrophysics Data System (ADS)

Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

2014-09-01

In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

Corrosion resistance of kolsterised austenitic 304 stainless steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abudaia, F. B., E-mail: fabudaia@yahoo.com; Khalil, E. O., E-mail: ekhalil9@yahoo.com; Esehiri, A. F., E-mail: Hope-eseheri@hotmail.co.uk

2015-03-30

Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtainedmore » for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe{sub 2}C{sub 5}. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.« less

Study on tea leaves extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

NASA Astrophysics Data System (ADS)

Hamdan, A. B.; Suryanto; Haider, F. I.

2018-01-01

Corrosion inhibitor from extraction of plant has been considered as the most preferable and most chosen technique to prevent corrosion of metal in acidic medium because of the environmental friendly factor. In this study, black tea leaves extraction was tested as corrosion inhibitor for mild steel in 0.1M of hydrochloric acid (HCl) with the absence and presence of corrosion inhibitor. The efficiency and effectiveness of black tea as corrosion inhibitor was tested by using corrosion weight loss measurement experiment was carried out with varies parameters which with different concentration of black tea extract solution. The extraction of black tea solution was done by using aqueous solvent method. The FT-IR result shows that black tea extract containing compounds such as catechin, caffeine and tannins that act as anti-corrosive reagents and responsible to enhance the effectiveness of black tea extract as corrosion inhibitor by forming the hydrophobic thin film through absorption process. As a result of weight loss measurement, it shows that loss in weight of mild steel reduces as the concentration of inhibitor increases. The surface analysis was done on the mild steel samples by using SEM.

Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb Bi at 450 and 550 °C

NASA Astrophysics Data System (ADS)

Kurata, Y.; Futakawa, M.; Saito, S.

2005-08-01

Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 °C and 550 °C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 °C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 °C. Corrosion depth of ferritic/martensitic steels also decreases at 550 °C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 °C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 °C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr.

Studying damage accumulation in martensitic corrosion-resistant steel under cold radial reduction

NASA Astrophysics Data System (ADS)

Karamyshev, A. P.; Nekrasov, I. I.; Nesterenko, A. V.; Parshin, V. S.; Smirnov, S. V.; Shveikin, V. P.; Fedulov, A. A.

2017-12-01

Cold radial reduction of specimens made of the Kh17N2 corrosion-resistant martensitic steel is studied on a lever-type radial-forging machine (RFM). The mechanical properties of the deformed specimens, the "damage accumulation - strain" relation in the specimens are obtained with the application of hydrostatic and fractographic methods for fractured specimens. The damage of the Kh17N2 corrosion-resistant steel is evaluated as a result of an experimental study considering the data of simulation by a complex finite element model of cold deformation on a lever-type RFM.

The Use of Vitreous Enamel Coatings to Improve Bonding and Reduce Corrosion in Concrete Reinforcing Steel

DTIC Science & Technology

2009-02-01

the Army, the Nation The Use of Vitreous Enamel Coatings to Improve Bonding and Reduce Corrosion in Concrete Reinforcing Steel Sean W. Morefield1...TITLE AND SUBTITLE The Use of Vitreous Enamel Coatings to Improve Bonding and Reduce Corrosion in Concrete Reinforcing Steel 5a. CONTRACT NUMBER...Concrete • Strategies to Prevent Corrosion • Alkali-resistant Vitreous Enamel Testing and Results • Ongoing Demonstration Work at CCAD • Summary U S

Inhibitory effect of xanthan gum and synergistic surfactant additives for mild steel corrosion in 1M HCl.

PubMed

Mobin, Mohammad; Rizvi, Marziya

2016-01-20

Natural polymer xanthan gum (XG) was investigated as eco friendly corrosion inhibitor for mild steel in 1M HCl at 30 °C, 40 °C, 50 °C and 60 °C, respectively. The inhibition studies were performed using gravimetric analysis, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), quantum chemical calculations, scanning electron microscopy (SEM), and UV-visible spectrophotometry. XG significantly reduces the corrosion rates of mild steel. The inhibition efficiency (IE) of the XG increased with increase in concentration, but decreased with temperature; the maximum IE of 74.24% was obtained at concentration of 1000 ppm at 30 °C. The inhibiting action of XG is synergistically enhanced on addition of very small amount of surfactants sodium dodecyl sulfate (SDS), cetyl pyridinium chloride (CPC) and Triton X-100 (TX). The effect of SDS is more pronounced than other surfactants. Potentiodynamic polarization studies confirm XG as a mixed type inhibitor. Results of weight loss measurements are in good agreement of the results of electrochemical measurements. The UV-visible spectroscopic results indicate the formation of complex between XG and Fe(2+) ions during corrosion reaction. Mechanism of inhibition was also investigated by calculating the thermodynamic and activation parameters like ΔG(0), Ea, ΔH and ΔS. The adsorption of inhibitor on mild steel surface obeys Langmuir adsorption isotherm. SEM micrographs show a clearly different morphology in presence of XG and XG-surfactant additives and confirmed the existence of an adsorbed protective film on the mild steel surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Atmospheric Corrosion on the Mechanical Properties of SAE 1020 Structural Steel

PubMed Central

Briones, Francisco; Villarroel, María; Vera, Rosa

2018-01-01

Resistance to atmospheric corrosion in different environments located in Chile and the corrosion’s effect on the mechanical properties of SAE 1020 steel were studied. Atmospheric corrosivity categories at each station under study were determined. These categories were C2, for Laja; C3 and C4, for the Arica and Antarctic stations, respectively; and the most aggressive, C5 and higher at Quintero. These specific environments significantly influenced the mechanical responses of steel exposed for 36 months. Rupture elongation, the modulus of toughness, ultimate tensile strength, and hardness of the material all decreased as a function of environmental atmospheric aggressiveness. Lowered ductility is the result of the increased corrosion rate due to the high deposition of chlorides. This is due to the morphology of material degradation, which consequently occurs as pores, microstrains, and other defects that promote early rupture of the steel. PMID:29641490

Treatment Prevents Corrosion in Steel and Concrete Structures

NASA Technical Reports Server (NTRS)

2007-01-01

In the mid-1990s, to protect rebar from corrosion, NASA developed an electromigration technique that sends corrosion-inhibiting ions into rebar to prevent rust, corrosion, and separation from the surrounding concrete. Kennedy Space Center worked with Surtreat Holding LLC, of Pittsburgh, Pennsylvania, a company that had developed a chemical option to fight structural corrosion, combining Surtreat's TPS-II anti-corrosive solution and electromigration. Kennedy's materials scientists reviewed the applicability of the chemical treatment to the electromigration process and determined that it was an effective and environmentally friendly match. Ten years later, NASA is still using this approach to fight concrete corrosion, and it has also developed a new technology that will further advance these efforts-a liquid galvanic coating applied to the outer surface of reinforced concrete to protect the embedded rebar from corrosion. Surtreat licensed this new coating technology and put it to use at the U.S. Army Naha Port, in Okinawa, Japan. The new coating prevents corrosion of steel in concrete in several applications, including highway and bridge infrastructures, piers and docks, concrete balconies and ceilings, parking garages, cooling towers, and pipelines. A natural compliment to the new coating, Surtreat's Total Performance System provides diagnostic testing and site analysis to identify the scope of problems for each project, manufactures and prescribes site-specific solutions, controls material application, and verifies performance through follow-up testing and analysis.

Stress corrosion cracking susceptibility of 18 Ni maraging steel

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Nelson, E. E.

1974-01-01

The stress corrosion cracking (SCC) resistance of 18Ni maraging steel (grades 200, 250, 300, and 350) was determined in 3.5 percent salt (NaCl) solution, synthetic sea water, high humidity, and outside MSFC atmosphere. All grades of the maraging steel were found to be susceptible to SCC in varying degrees according to their strengths, with the lowest strength steel (grade 200) being the least susceptible and the highest strength steel (grade 350), the most susceptible to SCC. The SCC resistance of 250 grade maraging steel was also evaluated in salt and salt-chromate solutions using fracture mechanics techniques. The threshold value, K sub SCC, was found to be approximately 44 MN/sq m square root m, (40 ksi square root in.) or 40 percent of the K sub Q value.

Adhesion of Bacillus subtilis and Pseudoalteromonas lipolytica to steel in a seawater environment and their effects on corrosion.

PubMed

Guo, Zhangwei; Liu, Tao; Cheng, Y Frank; Guo, Na; Yin, Yansheng

2017-09-01

In a marine environment, Bacillus subtilis and Pseudoalteromonas lipolytica are commonly found in the biofilms adherent to low-alloy engineering steel, and they have distinct effects on corrosion. In the present work, this phenomenon was investigated through the study of various materials characterization methods, electrochemical techniques, and contact angle measurements. It was found that the surface film formed on the steel in the presence of B. subtilis was compact, uniform, free of cracks, and hydrophobic. However, the film formed in the presence of P. lipolytica was loose, rough, heterogeneous, and hydrophilic. The main components of the films formed in the presence of B. subtilis and P. lipolytica were polysaccharides/TasA amyloid fibers and proteins/carboxylic acid, respectively. The composition, structure, and properties of the surface films formed on the steel were associated with different effects on corrosion. The presence of B. subtilis enhances the steel's resistance to corrosion, whereas corrosion was increased by the presence of P. lipolytica. In short, the compact and hydrophobic biofilm of B. subtilis appears to inhibit the corrosion of steel, while the loose, hydrophilic film of P. lipolytica tends to induce pitting corrosion. Copyright © 2017 Elsevier B.V. All rights reserved.

Corrosion of Pipeline and Wellbore Steel by Liquid CO2 Containing Trace Amounts of Water and SO2

NASA Astrophysics Data System (ADS)

McGrail, P.; Schaef, H. T.; Owen, A. T.

2009-12-01

Carbon dioxide capture and storage in deep saline formations is currently considered the most attractive option to reduce greenhouse gas emissions with continued use of fossil fuels for energy production. Transporting captured CO2 and injection into suitable formations for storage will necessarily involve pipeline systems and wellbores constructed of carbon steels. Industry standards currently require nearly complete dehydration of liquid CO2 to reduce corrosion in the pipeline transport system. However, it may be possible to establish a corrosion threshold based on H2O content in the CO2 that could allow for minor amounts of H2O to remain in the liquid CO2 and thereby eliminate a costly dehydration step. Similarly, trace amounts of sulfur and nitrogen compounds common in flue gas streams are currently removed through expensive desulfurization and catalytic reduction processes. Provided these contaminants could be safely and permanently transported and stored in the geologic reservoir, retrofits of existing fossil-fuel plants could address comprehensive emissions reductions, including CO2 at perhaps nearly the same capital and operating cost. Because CO2-SO2 mixtures have never been commercially transported or injected, both experimental and theoretical work is needed to understand corrosion mechanisms of various steels in these gas mixtures containing varying amounts of water. Experiments were conducted with common tool steel (AISI-01) and pipeline steel (X65) immersed in liquid CO2 at room temperature containing ~1% SO2 and varying amounts of H2O (0 to 2500 ppmw). A threshold concentration of H2O in the liquid CO2-SO2 mixture was established based on the absence of visible surface corrosion. For example, experiments exposing steel to liquid CO2-SO2 containing ~300 ppmw H2O showed a delay in onset of visible corrosion products and minimal surface corrosion was visible after five days of testing. However increasing the water content to 760 ppmw produced extensive

Synthesis, characterization and corrosion inhibition properties of benzamide-2-chloro-4-nitrobenzoic acid and anthranilic acid-2-chloro-4-nitrobenzoic acid for mild steel corrosion in acidic medium

NASA Astrophysics Data System (ADS)

Pandey, Archana; Verma, Chandrabhan; Singh, B.; Ebenso, Eno E.

2018-03-01

The present study deals with the synthesis of two new compounds namely, benzamide - 2-chloro-4-nitrobenzoic acid (BENCNBA) and anthranilic acid-2-chloro-4-nitrobenzoic acid (AACNBA) using solid phase reactions. The phase diagram studies revealed that formation of the investigated compounds occurs in 1:1 molar ratio. The synthesized compounds were characterized using several spectral techniques such as FT-IR, 1H and 13C NMR, UV-Vis, powder X-ray diffraction (PXRD). Single crystal XRD (SCXRD) study showed that both BENCNBA and AACNBA compounds crystallize in triclinic crystal system with P-1 space group. Further, the presence of intermolecular hydrogen bonding between the constituent components was also supported by single crystal X-ray diffraction (SCXRD) method. Heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions have also been computed using the enthalpy of fusion values derived from differential scanning calorimeter (DSC) study. The inhibition effect of BENCNBA and AACNBA on the mild steel corrosion in hydrochloric acid solution was tested using electrochemical methods. Electrochemical impedance spectroscopy (EIS) study revealed that both BENCNBA and AACNBA behaved as interface corrosion inhibitors and showed maximum inhibition efficiencies of 95.71% and 96.42%, respectively at 400 ppm (1.23 × 10-3 M) concentration. Potentiodynamic polarization (PDP) measurements suggested that BENCNBA and AACNBA acted as mixed type corrosion inhibitors. EIS and PDP results showed that BENCNBA and AACNBA act as efficient corrosion inhibitors for mild steel and their inhibition efficiencies enhances on increasing their concentrations.

Development of Custom 465® Corrosion-Resisting Steel for Landing Gear Applications

NASA Astrophysics Data System (ADS)

Daymond, Benjamin T.; Binot, Nicolas; Schmidt, Michael L.; Preston, Steve; Collins, Richard; Shepherd, Alan

2016-04-01

Existing high-strength low-alloy steels have been in place on landing gear for many years owing to their superior strength and cost performance. However, there have been major advances in improving the strength of high-performance corrosion-resisting steels. These materials have superior environmental robustness and remove the need for harmful protective coatings such as chromates and cadmium now on the list for removal under REACH legislation. A UK government-funded collaborative project is underway targeting a refined specification Custom 465® precipitation hardened stainless steel to replace the current material on Airbus A320 family aircraft main landing gear, a main fitting component developed by Messier-Bugatti-Dowty. This is a collaborative project between Airbus, Messier-Bugatti-Dowty, and Carpenter Technology Corporation. An extensive series of coupon tests on four production Heats of the material have been conducted, to obtain a full range of mechanical, fatigue, and corrosion properties. Custom 465® is an excellent replacement to the current material, with comparable tensile strength and fracture toughness, better ductility, and very good general corrosion and stress corrosion cracking resistance. Fatigue performance is the only significant area of deficit with respect to incumbent materials, fatigue initiation being often related to carbo-titanium-nitride particles and cleavage zones.

Evolution of Initial Atmospheric Corrosion of Carbon Steel in an Industrial Atmosphere

NASA Astrophysics Data System (ADS)

Pan, Chen; Han, Wei; Wang, Zhenyao; Wang, Chuan; Yu, Guocai

2016-12-01

The evolution of initial corrosion of carbon steel exposed to an industrial atmosphere in Shenyang, China, has been investigated by gravimetric, XRD, SEM/EDS and electrochemical techniques. The kinetics of the corrosion process including the acceleration and deceleration processes followed the empirical equation D = At n . The rust formed on the steel surface was bi-layered, comprised of an inner and outer layer. The outer layer was formed within the first 245 days and had lower iron content compared to the inner layer. However, the outer layer disappeared after 307 days of exposure, which is considered to be associated with the depletion of Fe3O4. The evolution of the rust layer formed on the carbon steel has also been discussed.

Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

NASA Astrophysics Data System (ADS)

Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

2015-12-01

The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

Corrosion protection of steel by thin coatings of starch-oil dry lubricants

USDA-ARS?s Scientific Manuscript database

Corrosion of materials is one of the most serious and challenging problems faced 3 worldwide by industry. This research investigated the inhibition of corrosive behavior a 4 dry lubricant formulation consisting of jet-cooked corn starch and soybean oil on SAE 5 1010 steel. Electrochemical Impedance ...

Corrosion of steel members strengthenened with carbon fiber reinforced polymer sheets

NASA Astrophysics Data System (ADS)

Bumadian, Ibrahim

Due to many years of service at several cases of exposure at various environments there are many of steel bridges which are in need of rehabilitation. The infrastructure needs upgrading, repair or maintenance, and also strengthening, but by using an alternative as retrofits methods. The alternative retrofit method, which used fiber reinforced polymer (FRP) composite materials which their strength materials comes largely from the fiber such as carbon, glass, and aramid fiber. Of the most important materials used in the rehabilitation of infrastructure is a composite material newly developed in bonded externally carbon fiber and polymer (CFRP) sheets, which has achieved remarkable success in the rehabilitation and upgrading of structural members. This technique has many disadvantages one of them is galvanic corrosion. This study presents the effect of galvanic corrosion on the interfacial strength between carbon fiber reinforced polymer (CFRP) sheets and a steel substrate. A total of 35 double-lap joint specimens and 19 beams specimens are prepared and exposed to an aggressive service environment in conjunction with an electrical potential method accelerating corrosion damage. Six test categories are planned at a typical exposure interval of 12 hours, including five specimens per category for double-lap joint specimens. And six test categories are planned at a typical exposure interval of 12 hours, including three specimens per category for Beam section specimens. In addition one beam section specimen is control. The degree of corrosion is measured. Fourier transform infrared (FTIR) reflectance spectroscopy has been used to monitor and confirm the proposed corrosion mechanisms on the surface of CFRP. In this study we are using FTIR-spectroscopic measurement systems in the mid infrared (MIR) wavelength region (4000 - 400) cm-1 to monitor characteristic spectral features. Upon completion of corrosion processes, all specimens are monotonically loaded until failure

Pitting corrosion resistant austenite stainless steel

DOEpatents

van Rooyen, D.; Bandy, R.

A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

Accumulation of radioactive corrosion products on steel surfaces of VVER type nuclear reactors. I. 110mAg

NASA Astrophysics Data System (ADS)

Hirschberg, Gábor; Baradlai, Pál; Varga, Kálmán; Myburg, Gerrit; Schunk, János; Tilky, Péter; Stoddart, Paul

Formation, presence and deposition of corrosion product radionuclides (such as 60Co, 51Cr, 54Mn, 59Fe and/or 110mAg) in the primary circuits of water-cooled nuclear reactors (PWRs) throw many obstacles in the way of normal operation. During the course of the work presented in this series, accumulations of such radionuclides have been studied at austenitic stainless steel type 08X18H10T (GOST 5632-61) surfaces (this austenitic stainless steel corresponds to AISI 321). Comparative experiments have been performed on magnetite-covered carbon steel (both materials are frequently used in some Soviet VVER type PWRs). For these laboratory-scale investigations a combination of the in situ radiotracer `thin gap' method and voltammetry is considered to be a powerful tool due to its high sensitivity towards the detection of the submonolayer coverages of corrosion product radionuclides. An independent technique (XPS) is also used to characterize the depth distribution and chemical state of various contaminants in the passive layer formed on austenitic stainless steel. In the first part of the series the accumulation of 110mAg has been investigated. Potential dependent sorption of Ag + ions (cementation) is found to be the predominant process on austenitic steel, while in the case of magnetite-covered carbon steel the silver species are mainly depleted in the form of Ag 2O. The XPS depth profile of Ag gives an evidence about the embedding of metallic silver into the entire passive layer of the austenitic stainless steel studied.

Rapid Tempering of Martensitic Stainless Steel AISI420: Microstructure, Mechanical and Corrosion Properties

NASA Astrophysics Data System (ADS)

Abbasi-Khazaei, Bijan; Mollaahmadi, Akbar

2017-04-01

In this research, the effect of rapid tempering on the microstructure, mechanical properties and corrosion resistance of AISI 420 martensitic stainless steel has been investigated. At first, all test specimens were austenitized at 1050 °C for 1 h and tempered at 200 °C for 1 h. Then, the samples were rapidly reheated by a salt bath furnace in a temperature range from 300 to 1050 °C for 2 min and cooled in air. The tensile tests, impact, hardness and electrochemical corrosion were carried out on the reheated samples. Scanning electron microscopy was used to study the microstructure and fracture surface. To investigate carbides, transmission electron microscopy and also scanning electron microscopy were used. X-ray diffraction was used for determination of the retained austenite. The results showed that the minimum properties such as the tensile strength, impact energy, hardness and corrosion resistance were obtained at reheating temperature of 700 °C. Semi-continuous carbides in the grain boundaries were seen in this temperature. Secondary hardening phenomenon was occurred at reheating temperature of 500 °C.

Cyclic fatigue of a high-strength corrosion-resistant sheet TRIP steel

NASA Astrophysics Data System (ADS)

Terent'ev, V. F.; Alekseeva, L. E.; Korableva, S. A.; Prosvirnin, D. V.; Pankova, M. N.; Filippov, G. A.

2014-04-01

The mechanical properties of 0.3- and 0.8-mm-thick high-strength corrosion-resistant TRIP steel having various levels of strength properties are studied during static and cyclic loading in the high-cycle fatigue range. The fatigue fracture surface is analyzed by fractography, and the obtained results demonstrate ductile and quasi-brittle fracture mechanisms of this steel depending on the strength properties of the steel and the content of deformation martensite in it.

Corrosive Metabolic Activity of Desulfovibrio sp. on 316L Stainless Steel

NASA Astrophysics Data System (ADS)

Arkan, Simge; Ilhan-Sungur, Esra; Cansever, Nurhan

2016-12-01

The present study investigated the effects of chemical parameters (SO4 2-, PO4 3-, Cl-, pH) and the contents of extracellular polymeric substances (EPS) regarding the growth of Desulfovibrio sp. on the microbiologically induced corrosion of 316L stainless steel (SS). The experiments were carried out in laboratory-scaled test and control systems. 316L SS coupons were exposed to Desulfovibrio sp. culture over 720 h. The test coupons were removed at specific sampling times for enumeration of Desulfovibrio sp., determination of the corrosion rate by the weight loss measurement method and also for analysis of carbohydrate and protein in the EPS. The chemical parameters of the culture were also established. Biofilm/film formation and corrosion products on the 316L SS surfaces were investigated by scanning electron microscopy and energy-dispersive x-ray spectrometry analyses in the laboratory-scaled systems. It was found that Desulfovibrio sp. led to the corrosion of 316L SS. Both the amount of extracellular protein and chemical parameters (SO4 2- and PO4 3-) of the culture caused an increase in the corrosion of metal. There was a significantly positive relationship between the sessile and planktonic Desulfovibrio sp. counts ( p < 0.01). It was detected that the growth phases of the sessile and planktonic Desulfovibrio sp. were different from each other and the growth phases of the sessile Desulfovibrio sp. vary depending on the subspecies of Desulfovibrio sp. and the type of metal when compared with the other published studies.

The Effect of Fly Ash on the Corrosion Behaviour of Galvanised Steel Rebarsin Concrete

NASA Astrophysics Data System (ADS)

Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

2017-08-01

The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.

The influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes in seawater

NASA Astrophysics Data System (ADS)

Bai, Qiang; Zou, Yan; Kong, Xiangfeng; Gao, Yang; Dong, Sheng; Zhang, Wei

2017-02-01

The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.

Corrosion behavior of stainless steel weldments in physiological solutions

NASA Astrophysics Data System (ADS)

Farooq, A.; Azam, M.; Deen, K. M.

2018-01-01

In this study corrosion behavior of TIG welded 316L stainless steel plates in simulated biological solutions is investigated. The mechanical testing results showed slight decrease in ductility after welding and the fracture surface represented mixed cleavage and inclusions containing dimple structure. The heat affected and weld zone (WZ) demonstrated higher corrosion potential and relatively large pitting tendency than base metal (BM) in both Hank’s and Ringer’s solution. The formation of delta (δ) ferrite in the heat affected and WZ decreased the corrosion resistance as confirmed from potentiodynamic Tafel scans. The decrease in pitting resistance and lower protection tendency of the WZ compared to BM and heat affected zone was also quantified from the cyclic polarization trends.

Corrosion protection service life of epoxy-coated reinforcing steel in Virginia bridge decks.

DOT National Transportation Integrated Search

2003-01-01

The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare steel bars from 10 Virginia bridge decks built between 1981 and 1995. The objective was to determine the corrosion p...

Corrosion Performance of Stainless Steels in a Simulated Launch Environment