Showing papers in "Corrosion in 1993"
TL;DR: In this article, electrochemical impedance spectroscopy (EIS) technique was used to evaluate the water transport (diffusion and equilibrium water uptake) and the dielectric properties of freestanding polyimide (Kapton® and PMDA-ODA) and polyethyleneterephthalate (PET) membranes at 25 and 40°C, respectively, and in supported PDE-coated metals.
Abstract: The electrochemical impedance spectroscopy (EIS) technique was used to evaluate the water transport (diffusion and equilibrium water uptake) and the dielectric properties of freestanding polyimide (Kapton® and PMDA-ODA) and polyethyleneterephthalate (PET) membranes at 25 and 40°C, respectively, and in supported PMDA-ODA-coated metals. Permeability and diffusion coefficients of freestanding films were also obtained by using the Payne cup method and the MacBain quartz spring balance in order to assess the reliability of the EIS method when compared to other techniques. Results from this work show that the diffusivity of water in polyimide films varies from 1.42 × 10−9 to 3.53 × 10−9 cm2 s−1 for thickness between 2.4 and 125 μm, while the equilibrium water uptake varies from 2.31 to 4.63% by weight for the same range of thickness. The average calculated dielectric constant of the freestanding Kapton® films is 4.5. Water diffusion coefficient in PET varies from 2.11 × 10−9 to 12.61 × 10−9 cm2 s−1 for...
197 citations
TL;DR: In this article, a theoretical analysis of the impedance of polymer-coated steel was performed to identify parameters for assessing coating performance in a short time without rigorous analysis of data from the data collection process.
Abstract: A theoretical analysis of the impedance of polymer-coated steel was performed to identify parameters for assessing coating performance in a short time without rigorous analysis of data fro...
146 citations
TL;DR: In this paper, the authors studied the corrosion of mild steel under completely anaerobic conditions in the presence of a mixed population biofilm, including sulfate-reducing bacteria (SRB), in a continuous flow system.
Abstract: Corrosion of mild steel under completely anaerobic conditions in the presence of a mixed population biofilm, including sulfate-reducing bacteria (SRB), has been studied in a continuous flow system. The closed channel flow reactor was continuously fed with low concentration substrate at different dilution rates that influenced biofilm accumulation. No direct correlation was observed between corrosion and SRB activity in the absence of ferrous iron. Furthermore, corrosion of mild steel in the SRB environment was determined by the nature of the metal and environmental conditions such as dissolved iron concentration. When formation of an iron sulfide film on mild steel was prevented before the biofilm accumulated, the metal surface retained its scratch lines after a 21-day experiment (SRB at 2.6 × 109/cm2). However, when the iron sulfide film was formed before the accumulation of biofilm, visible localized corrosion appeared after 14 days and increased up to 21 days. Intergranular and pitting attack ...
146 citations
TL;DR: In the field, concrete often has cracks that extend to the reinforcing steel as discussed by the authors, which is typically in uncracked concrete, but concrete can also have cracks in steel reinforcing steel.
Abstract: Corrosion of steel in concrete is studied typically in uncracked concrete. In the field, however, concrete often has cracks that extend to the reinforcing steel. Electrochemical corrosion ...
138 citations
TL;DR: In this paper, the authors used gasometry, mass loss, and direct current (DC) polarization techniques to study acid corrosion inhibitors at 30°C for steel in 0.5 M H2SO4 using gasometry and mass loss.
Abstract: Five selected S-alkylisothisothiouronium iodides have been studied as acid corrosion inhibitors at 30°C for steel in 0.5 M H2SO4 using gasometry, mass loss, and direct current (DC) polarization techniques. All of the data reveal that the compounds act as inhibitors in the acid environments; furthermore, polarization curves show that the compounds act as mixed-type inhibitors. It was found that the inhibition efficiency increases with the increase of the length of the additive alkyl chain. Langmuir's adsorption isotherms fit the experimental data for the studied compounds. Thermodynamic parameters were obtained from experimental data of the temperature studies of the inhibition process at five temperatures ranging from 30 to 70°C. It was observed that the activation energy is slightly increased with the increase of the additive alkyl chain. On the other hand, the sudden large increase of the inhibition behavior of S-hexylisothiouronium iodide was attributed to a different adsorption process.
111 citations
TL;DR: In this article, a direct current polarization (DCP) was used to degrade carbon steel components in sulfur-containing environments, which is a major concern in oil and gas production, and the results showed that the DCP was effective in reducing carbon steel degradation.
Abstract: The chemical degradation of carbon steel components in sulfur-containing environments is a major concern in oil and gas production. In a previous study, a direct current (DC) polarization ...
104 citations
TL;DR: The relationship of laboratory fluid flow corrosion test techniques to flow-accelerated corrosion in field applications and the parameters required to apply laboratory data effectively in the field were studied in this paper, where single-phase, aqueous, sweet corrosion of steel in turbulent pipe flow (12.7 mm and 25.4 mm diam) was correlated to corrosion in jet impingement and rotating cylinder tests.
Abstract: The relationship of laboratory fluid flow corrosion test techniques to flow-accelerated corrosion in field applications and the parameters required to apply laboratory data effectively in the field were studied. Single-phase, aqueous, sweet corrosion of steel in turbulent pipe flow (12.7 mm and 25.4 mm diam) was correlated to corrosion in jet impingement and rotating cylinder tests. All tests were conducted simultaneously, using the same test fluid to minimize environmental variables and to allow a direct, realistic comparison of test methods. Rotating cylinder electrode corrosion rates did not correlate with pipe flow based on wall shear stress or mass transfer for flow-accelerated corrosion of carbon (C) steel in the environment studied. Jet impingement corrosion rates for the test ring at r/r0=3 correlated with pipe flow based on wall shear stress. The general equation for flow-accelerated corrosion of C steel under turbulent flow conditions in this environment was expressed as: Rcorr = a τwb ...
101 citations
TL;DR: In this paper, Nitrogen Alloying was found to inhibit active dissolution and to introduce a secondary loop with fluctuating currents in the anodic polarization curve of type 316LN stainless steel (SS) (UNS S31653) in 1 N hydrochloric acid (HCl) solution.
Abstract: Nitrogen (N) alloying was found to inhibit active dissolution and to introduce a secondary loop with fluctuating currents in the anodic polarization curve of type 316LN stainless steel (SS) (UNS S31653) in 1 N hydrochloric acid (HCl) solution Potentiostatic tests in this potential range confirmed the occurrence of current transients as a result of metastable pits, resulting in secondary loop formation Higher minimum chloride (Cl−) concentration and low acidic pH were shown to be required for stable pit formation in type 316LN SS compared to similar alloys without N alloying Results showed no selective anodic dissolution of any of the alloying elements in actively growing pits in type 316LN SS Although ammonium ions (NH4+) were found within pits under suitable applied potentials in 1 N HCl and under natural corrosion in ferric chloride (FeCl3) solutions, the more anodic the potential, the less was its yield The formation of NH4+ ions was found to be greater at more active potentials under uni
87 citations
TL;DR: Using potentiodynamic and transient electrochemical methods and weight loss, N-alkylbetaines are shown to be good inhibitors of iron corrosion in HCl at concentrations around the critical point as discussed by the authors.
Abstract: Using potentiodynamic and transient electrochemical methods and weight loss shows that N-alkylbetaines are good inhibitors of iron corrosion in HCl at concentrations around the critical mi...
86 citations
TL;DR: In this article, the authors used repassivation potential as a parameter for the long-term prediction of pitting resistance of two Fe-Ni-Cr-Mo alloys that are candidate materials for high level nuclear waste containers.
Abstract: Repassivation potential (Erp) was investigated for use as a parameter in the long-term prediction of pitting resistance of two Fe-Ni-Cr-Mo alloys that are candidate materials for high-level nuclear waste containers. This potential was found to be independent of the extent of prior pit growth for alloy 825 (UNS N08825) and type 316L (UNS S31603) stainless steel (SS). Repassivation potential decreased by an increase in backward scan rate after pits were grown under potentiostatic conditions. This was related to the effect of potential on repassivation time. The corrosion potential (Ecorr) in simulated pit-crevice solutions increased with a decrease in pH and was independent of chloride (Cl−) concentration even to the point of depassivation. The depassivation pH (pHD) was independent of Cl− concentration and increased slightly with an increase in temperature. The relationship between repassivation potential and Ecorr in simulated pit solutions was discussed. It was hypothesized that the repassivatio...
81 citations
TL;DR: A 20min treatment in 1.0 mol/L of aminotrimethylidenephosphonic acid (ATMP) with a pH 0.23 at 45°C formed an anti-corrosive complex film that was composed of 48.4% O, 28.6% P, 7.0% Fe, 4.3% N, and 11.7%C, based on x-ray photoelectron spectroscopy and Auger electron analysis as discussed by the authors.
Abstract: For protecting mild steel from corrosion, aminotrimethylidenephosphonic acid (ATMP) was more effective than 1-hydroxyethylidene diphosphonic acid (HEDP), N.N-dimethylidenephosphonoglycine (DMPG), 1-ethyl-phosphonoethylidenediphosphonic acid (EEDP), and ethylenediaminetetramethylidenephosphonic acid (EDTMP). A 20-min treatment in 1.0 mol/L of ATMP with a pH 0.23 at 45°C formed an anti-corrosive complex film that was composed of 48.4% O, 28.6% P, 7.0% Fe, 4.3% N, and 11.7%C, based on x-ray photoelectron spectroscopy and Auger electron spectroscopy. From differences in binding energies of Fe, N, and O, in the shift of C-N and P-O vibration, in the reflection FTIR spectra, and in the change of P-OH and Fe-N vibration before and after film formation, it was deduced that N and O in ATMP were coordinated with Fe2+ in the film.
TL;DR: In this paper, Thiosulfate ion was used as a substitute for hydrogen sulfide (H2S) to simulate stress corrosion cracking (SCC) of corrosion-resistant alloys (CRAs) and sulfide stress cracking (SSC) of high-strength, low-alloy steels.
Abstract: Thiosulfate ion was used as a substitute for hydrogen sulfide (H2S) to simulate stress corrosion cracking (SCC) of corrosion-resistant alloys (CRAs) and sulfide stress cracking (SSC) of high-strength, low-alloy steels. Several SCC tests using a variety of stress application techniques showed the brine containing thiosulfate exhibited similar severity to brine containing H2S in regard to SCC when plastic strain was applied to the CRAs. Materials that exhibited SCC susceptibility in brine containing thiosulfate agreed well the SCC susceptibility of those in brine containing H2S. Types 304 (UNS S30400) and 316L (UNS S31603) stainless steels and duplex stainless steel exhibited in both environments. However, high-nickel austenitic alloys such as alloys 904L (UNS N08904) and 825 (UNS N08825) did not. A 10−3 to 10−2 mol/l S2O32− addition in 20% NaCl aqueous solution at 353 K corresponded to H2S of 0.1 to 1 MPa at 473 K. The SSC susceptibilities of high-strength, low-alloy steels in a 10−3 mol/l S2O32− ...
TL;DR: A new type of passivity in carbon (C) steels that occurs in the correct range of carbon dioxide (CO2), bicarbonate (HCO3−), sodium chloride (NaCl), and potential was discovered as discussed by the authors.
Abstract: A new type of passivity in carbon (C) steels that occurs in the correct range of carbon dioxide (CO2), bicarbonate (HCO3−), sodium chloride (NaCl), and potential was discovered. C steels n...
TL;DR: The role of different inorganic cations of several elements and organic materials in combination with different concentrations of propargyl alcohol (PA) was investigated in an effort to control the dissolution of mild steel in boiling (102 ± 1°C) hydrochloric acid (HCl) solution.
Abstract: The role of different inorganic cations of several elements and organic materials in combination with different concentrations of propargyl alcohol (PA) was investigated in an effort to control the dissolution of mild steel in boiling (102 ± 1°C) hydrochloric acid (HCl) solution. Inorganic cations of chromium (Cr6+), arsenic (As3+), tin (Sn2+), copper (Cu2+), nickel (Ni2+), and mercury (Hg2+) were studied. Organic materials studied included phenol, formaldehyde, O-aminobenzoic acid, sodium hypophosphide, and hydroquinone. Cr6+, As3+, and Ni2+ provided higher synergism, followed by Cu2+, Sn2+, and Hg2+. Phenol and formaldehyde provided higher beneficial effect. Except for phenol and formaldehyde, the other organics stimulated corrosion when added at higher concentrations. Organic additives were more effective than inorganic cations. Cu2+, Cr6+, and Ni2+ accelerated corrosion when used without PA but strongly reduced dissolution in its presence. As3+ reduced the corrosion rate alone and in combinat...
TL;DR: In this article, the effect of the thiourea group of sulfur compounds on the corrosion reaction and the amount of H2 absorbed by mild steel in 1 N H2SO4 at 40°C was studied.
Abstract: The thiourea group of sulfur compounds has important theoretical and practical applications. Thioureas have been studied extensively, but their inhibition mechanism is not fully understood. The effect of thiourea; allylthiourea; N,N′-diethylthiourea; N,N′-di-isopropylthiourea; phenylthiourea; thiocarbanilide; and symdiotolylthiourea on the corrosion reaction and on the amount of H2 absorbed by cold-rolled mild steel in 1 N H2SO4 at 40°C was studied. Inhibitor efficiency increased with increases in molecular weight and inhibitor concentration. Higher inhibitor concentrations decreased H2 pickup. Thiourea accelerated corrosion reactions and H2 pickup at higher concentrations. Potential studies showed cathodic reactions was inhibited at lower concentrations and anodic reactions were inhibited at higher concentrations. Results were based on the adsorption theory, and all inhibitors studied followed the Langmuir isotherm.
TL;DR: In this article, the effects of small-amplitude cyclic loading on threshold stress, together with the increase of crack nucleation and the decrease of average crack growth rates with increasing test times, were studied in a range of pipeline steels immersed in a carbonate-bicarbonate solution.
Abstract: Stress corrosion cracking (SCC) characteristics of a range of pipeline steels immersed in a carbonate-bicarbonate solution were studied in terms of the deleterious effects of small-amplitude cyclic loading on threshold stress, together with the increase of crack nucleation and the decrease of average crack growth rates with increasing test times. Data were reported on conditions for coalescence or otherwise of adjacent cracks in terms of spatial separation. The time dependence of crack nucleation rates and crack growth in laboratory tests varied with stress. The laboratory rates for crack nucleation and growth likely are applicable in high-pressure gas transmission pipelines in service, but values of the constants in the power law expressions for those rates differed for service conditions. The data showed service condition calculations can be guided by empirically assigning ranges of values for the constants by imposing boundary conditions that relate to service experience. Ranges of values also...
TL;DR: In this article, the effects of temperature on stress corrosion crack growth rates were studied on three heats of sensitized type 304 (UNS S30400) stainless steel (SS) and one heat of Sensitized alloy 600 (N06600), using reversed direct current (DC) potential drop crack length monitoring on 25mm compact-type (CT) specimens in 25°C to 288°C water, usually containing 200 ppb oxygen (O2).
Abstract: Effects of temperature on stress corrosion crack growth rates were studied on three heats of sensitized type 304 (UNS S30400) stainless steel (SS) and one heat of sensitized alloy 600 (UNS N06600). Data were obtained using reversed direct current (DC) potential drop crack length monitoring on 25-mm compact-type (CT) specimens in 25°C to 288°C water, usually containing 200 ppb oxygen (O2). Most data were obtained in 0.3 μM sulfuric acid (0.267 μS/cm). In one heat, 0.1 μM hydrochloric acid (HCl) (0.076 μS/cm), 0.5 μM HCl (0.224 μS/cm), and air-saturated water (≈ 8,800 ppb O2 and ≈ 0.5 μS/cm) also were evaluated. All heats and materials had similar temperature dependence and showed a peak in crack growth rate at ≈ 200°C in these water chemistries, which typically was a factor of 30 to 100 times higher than at 288°C or 25°C. Growth rates decreased rapidly above 250°C compared to those between 25°C and 200°C. In many cases, similar rates were observed at 25°C and 288°C. Data were compared with the lit...
TL;DR: In this paper, three laboratory-based accelerated corrosion tests were investigated to develop improved procedures for assessing corrosion protection properties of organic paint films, including standard salt-spray (ASTM Standard B-117), a wet/dry cycle corrosion test using a low-concentration ammonium sulfate/sodium chloride [(NH4)2SO4/ NaCl] electrolyte, and a corrosion/weathering test combining wet/ dry corrosion cycles with ultraviolet (UV) condensation cycles.
Abstract: Three laboratory-based accelerated corrosion tests were investigated to develop improved procedures for assessing corrosion protection properties of organic paint films. The methods investigated were: standard salt-spray (ASTM Standard B-117), a wet/dry cycle corrosion test using a low-concentration ammonium sulfate/sodium chloride [(NH4)2SO4/ NaCl] electrolyte, and a corrosion/weathering test combining wet/dry corrosion cycles with ultraviolet (UV) condensation cycles. Results were reported for an epoxy-polyamide/ Polyurethane paint system on phosphated steel and for an alkyd/alkyd system on cold-rolled steel. Corrosion and paint degradation were assessed visually and by scanning electron microscopy and x-ray photoelectron spectroscopy. Salt-spray testing resulted in corrosion, blistering, and paint degradation that appeared unrealistic compared to results after 12-month exterior exposures to natural industrial atmospheres. Wet/dry cycle corrosion testing produced paint delamination from scribe ...
TL;DR: In this article, the influence of heat treatment on the corrosion behavior of Mg-aluminum alloys was investigated by studying the electrochemical properties of the alloys in the solution-treated (T4) and artificially aged (T6) conditions.
Abstract: The influence of heat treatment on corrosion behavior of magnesium-aluminum (Mg-9Al) alloys was investigated by studying the electrochemical properties of Mg-9Al in the solution-treated (T4) and artificially aged (T6) conditions. The alloys' properties were compared to those of pure Mg, the intermetallic Mg17Al12 phase, and different Mg-Al-based alloys (Mg-3Al, AZ91). The Mg-9Al alloy exhibited better corrosion resistance in the T6 condition than in the T4 condition because of the intermetallic Mg17Al12 precipitates present in the T6 alloy. The mechanism responsible for this behavior was attributed to a more protective porous film on the T6 matrix alloy than on the T4 alloy. Adition of zinc did not modify these results. Localized corrosion testing showed the Mg-Al alloys were attacked preferentially in relation to magnesium silicide (Mg2Si) precipitates which were characterized clearly using metallurgical examinations.
TL;DR: Erosion rates were measured along the length of a tubular flow cell of type 304 (UNS S30400) stainless steel (SS) carrying dilute slurries of silica sand (0.43 mm diam) and smooth glass be...
Abstract: Erosion rates were measured along the length of a tubular flow cell of type 304 (UNS S30400) stainless steel (SS) carrying dilute slurries of silica sand (0.43 mm diam) and smooth glass be...
TL;DR: In this article, the compressive forces generated by voluminous grain boundary corrosion products were investigated by measuring the forces of under-aged, over-aged and peak-aged aluminum-lithium (Al-Li) alloy 8090 (UNS A98091) in plate and sheet form.
Abstract: Exfoliation of aluminum-lithium (Al-Li) alloy 8090 (UNS A98091) in plate and sheet form was studied by measuring the compressive forces generated by voluminous grain boundary corrosion products. The forces were shown to be related closely to grain shape, with more elongated microstructures generating higher forces. Aging treatment of the alloy also was a factor. Corrosion product forces were ranked in the order: under-aged > over-aged > peak-aged. High susceptibility of the over-aged temper in 8090 differed from that of conventional, precipitation-hardened Al alloys and was attributed to the formation of anodic phases in the Li-containing material. Stress corrosion tests were performed on the plate using double-cantilever beam specimens. The sheet was tested under constant load in the through-thickness direction. KISCC values, the limiting values of stress intensity for stress corrosion to occur, were compared with the maximum corrosion product forces and supported the proposition that exfoliatio...
TL;DR: In this article, the corrosive wear behavior of high-alloy stainless steels under sliding conditions was investigated in 20 wt% sulfuric acid (H2SO4) solution.
Abstract: The corrosive wear behavior of high-alloy stainless steels (SS) under sliding conditions was investigated in 20 wt% sulfuric acid (H2SO4) solution. Experiments showed a negative shift of the corrosion potential, positive shift of critical passivation potential, and steady passivation potential could be regarded as accelerative effects of wear on corrosion. For 18-8 austenitic SS (UNS S30302), it was concluded that the accelerative effect of wear on corrosion increased with increases of the corrosion rate.
TL;DR: In this article, the effects of alloying elements such as niobium, copper, chromium, molybdenum, and titanium in high-strength, low-alloy steels on hydrogen induced cracking (HIC) were investigated.
Abstract: The effects of alloying elements such as niobium, copper, chromium, molybdenum, and titanium in high-strength, low-alloy (HSLA) steels on hydrogen induced cracking (HIC) were investigated. The HIC test was performed to NACE TM-02-84 in BP (saturated H2S synthetic sea water) and NACE solutions. The test data were analyzed with an optical microscope, scanning electron microscope, electron probe microanalyzer, Auger electron spectrometer, transmission electron microscope, and an image analyzer. Results showed the addition of Nb increased the aspect ratio of inclusions and decreased HIC resistance. In BP solution, Cu-bearing steel formed a protective film of γ-Fe2O3 enriched with Cu on the outside and FeS on the inside. Cr and Mo showed a synergistic effect on the formation of low-temperature transformation products and the increase of HIC sensitivity. The suitable parameter for these two elements on HIC sensitivity was , and the critical value of this parameter was 0.1%. Additionally, coarse TiN pre...
TL;DR: In this article, the corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined.
Abstract: The corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined. Critical pitting temperatures were determined in ferric chloride (FeCl3). Passive film breakdown potentials were assessed from potentiodynamic scans in 3% sodium chloride (NaCl) at 50°C. Potentiodynamic and potentiostatic tests were carried out in 30% sulfuric acid (H2SO4) at 25°C, which was representative of chloride-free acid media of low redox potential. Metallographic examination and microanalysis were conducted on the test welds. Because of segregation of alloying elements, weld metal pitting resistance always was lower than that of matching composition base steel. The difference increased with higher Cr, Mo, and N contents. Segregation also reduced resistance to general corrosion in H2SO4, but the effect relative to the base steel was less marked than with chloride pitting. Segregation of Cr, Mo, and N in ...
TL;DR: Localized pitting is best described by a characteristic parameter called the pitting potential value (Ep), which is governed by a number of factors, including alloy composition, meta-composition, etc..
Abstract: Localized pitting is best described by a characteristic parameter called the pitting potential value (Ep). Although Ep is governed by a number of factors, including alloy composition, meta...
TL;DR: In this paper, the corrosion rate of reinforcing steel in concrete structures was evaluated using three devices, two of which operated on the principle of linear polarization with or without signal confinement, and the third was based on superimposed current pulses of high and low frequency with signal confinement.
Abstract: This study was undertaken to obtain data for development of a methodology and standard for instruments to evaluate the corrosion rate of steel in concrete structures. Measurements of the polarization resistance of reinforcing steel were made with three devices, two of which operated on the principle of linear polarization with or without signal confinement. The third was based on superimposed current pulses of high and low frequency with signal confinement. Bridges were chosen as representative of three environmental conditions: marine environments, regions with mild winters and low use of deicing agents, and regions with cold winters and characterized by extensive use of deicing agents. Measurement procedures were described, and the data obtained were presented on plots of corrosion current (ic) vs corrosion potential (Ec). Values for ic were low and almost independent of Ec when Ec was more noble than about −0.25 V (Cu/CuSO4), Currents increased as Ec shifted in the negative direction. Values o...
TL;DR: In this paper, the quantitative relations between the corrosion rate (in terms of the corrosion current density, Icorr) of steel in concrete and the electrolyte supply was studied.
Abstract: The quantitative relations between the corrosion rate (in terms of the corrosion current density, Icorr) of steel in concrete and the electrolyte supply was studied. The degree of pore saturation of concrete determined the type of natural control of the corrosion kinetics of the embedded steel. Corrosion of steel in atmosphere and in concrete in an active state conformed to a semi-logarithmic relationship between Icorr and the relative humidity (RH) of the atmosphere or the degree of pore saturation of the concrete. The latter variable dictated resistivity of the concrete. However, once corrosion at a steel-concrete interface started, it was found that the concrete cover could be detrimental to the corrosion process of the embedded steel. The porous nature of the concrete resulted in longer wetting times than bare steel surfaces.
TL;DR: In this article, the effects of dissolved oxygen, hydrogen, and hydrogen peroxide on the corrosion potentials of type 304 SS and alloy 182 in simulated boiling water reactor (BWR) coolant environments under various water chemistry conditions at 288°C are reported.
Abstract: The effects of dissolved oxygen, hydrogen, and hydrogen peroxide on the corrosion (electrochemical) potentials (ECPs) of type 304 SS and alloy 182 in simulated boiling water reactor (BWR) coolant environments under various water chemistry conditions at 288°C are reported. In oxygenated systems, the measured ECP fell within the range +20 to −600 mV (vs SHE) depending on the O2 concentration. The effect of water flow rate on the ECP was also studied as function of dissolved O2 concentration. Increasing flow rate at constant oxygen concentration increased the ECPs of type 304 SS and alloy 182. The effect of hydrogen peroxide (H2O2) on the ECP of type 304 SS and alloy 182 in pure water was also determined. The authors found that the concentration of oxygen and the ECP increased immediately when H2O2 was injected into the cell. The measured corrosion potentials of both alloys were 200 to 400 mV more positive than for dissolved O2 at similar levels. However, the ECP was lower than that expected theoret...
TL;DR: In this paper, the authors reviewed the structure, constitution, preparation, and characterization of green rust, a stable corrosion product at high pH and low Eh in the presence of chloride.
Abstract: Studies of the corrosion of pure iron showed green rust, approximately Fe42+ Fe23+ (OH)12(Cl,OH)2, was a stable corrosion product at high pH and low Eh in the presence of chloride. The structure, constitution, preparation, and characterization of green rust was reviewed. A diagram relevant to the corrosion of iron in cement, constructed for pH 12, showed stability fields of green rust, α, δ FeO(OH), and β FeO(OH,Cl). Overall implications of chloride to the corrosion process were investigated.
TL;DR: In this paper, the effects of fluid flow on the corrosion resistance of oil well materials in environments containing CO2 were studied using two experimental techniques: weight loss measurements and a large flow loop that could attain a maximum liquid flow rate of 20 m/s.
Abstract: Effects of fluid flow on the corrosion resistance of oil well materials in environments containing CO2 were studied using two experimental techniques. One method utilized weight loss measurements and a large flow loop that could attain a maximum liquid flow rate of 20 m/s. The other utilized electrochemical measurements with rotating electrodes. The corrosion rate of carbon steel measured in the flow loop increased with the flow rate. But, the corrosion rate of 13Cr martensitic stainless steel (UNS S42000) increased to 0.5 mm/y to become constant at the flow rate of 3 m/s. Corrosion rates were obtained from the electrochemical data using the Stern-Geary method, as a function of the speed of rotation. The results obtained by the two experimental methods were compared by hydrodynamic analysis. Using the similarity solutions obtained for mass transfer with pipe flow and the rotating electrode, the rotating velocity was converted to the equivalent velocity in the pipe. On that basis, the corrosion ra...