Corrosion behavior of low alloy steels containing Cr, Co and W in synthetic potable water (original) (raw)
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Applied Surface Science, 2011
The efficiency of a formula containing 2-{(2-hydroxyethyl)[(4-methyl-1H-1,2,3-benzotriazol-1yl)methyl]amino}ethanol (tolyltriazole) and decanoic acid as corrosion inhibitor for galvanized steel and electroplating steel in aqueous solution have been determined by electrochemical impedance spectroscopy (EIS) techniques. The experimental data obtained from this method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPE) has been used. The corrosion behaviour in the presence of different concentration of decanoic acid (DA) in the formula was also investigated by EIS. Results obtained reveal that, the formula is a good inhibitor for galvanized steel and electroplating steel in aqueous solution, the better performance was obtained in the case of galvanized steel. The ability of the inhibitor to be adsorbed on the surface was dependent on the nature of metal. X-ray photoelectron spectroscopy surface analysis with inhibitor shows that it's chemisorbed at the galvanized and electroplating steel/aqueous solution interface.
Electrochem
The electrochemical behavior of low alloyed Fe-Cr steels with 3 and 5% wt. of Cr in neutral Na2SO4 electrolyte combined with a detailed chemical and morphological characterization of these alloys performed by Auger electron spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and scanning electron microscopy are presented here. The corrosion of low alloyed Fe-Cr steels proceeds in the prepassive range, with the formation of corrosion surface films having a duplex structure with outer iron oxide/hydroxide layer and inner Cr oxide-rich layer. The thickness, composition, and the morphology of the surface films vary as a function of chromium content in the alloy as well as conditions of electrochemical tests (temperature). Even a low chromium content shows a beneficial effect on the corrosion performances of the Fe-Cr steels. The chromium as a more active component than iron of ferrite increases the anodic activity of this phase, which results i...
Low alloy steels are widely employed for boiler tubing and steam piping in thermal power plants. This is mainly due to its excellent oxidation and corrosion resistance as well as superior strength at high temperature and pressure. Scale formation in internal surface of boiler tubes is one of the major problems in most of highpressure boilers of thermal power stations. Two major problems result from deposit fouling on the interior tube surfaces: (1) Loss of heat transfer, and (2) Under-deposit corrosion. Therefore, it is necessary to clean the heat transfer surfaces to remove scale formed during normal operation, in order to minimize corrosion and maintain the desired heat transfer capabilities of industrial equipment. Mineral acids are typically employed for this purpose. The present study addresses the corrosion behavior of two low alloy steels (ASTM A213 grade T22 and T92) in hydrochloric and sulfuric acid solutions at different temperatures and stirring velocities using gravimetric test, electrochemical impedance spectroscopy (EIS) method and the new technique electrochemical frequency modulation (EFM).
Molecules, 2014
In this study, we compared the electrochemical corrosion behavior of a newly fabricated nanocrystalline pure aluminum to another microcrystalline aluminum using various electrochemical techniques in natural Arabian Gulf seawater. The nanocrystalline Al was fabricated using mechanical alloying technique. Cyclic potentiodynamic polarization showed that microcrystalline has lower corrosion current and corrosion rate with higher polarization resistance compared to the nanocrystalline Al. The change of current with time at -550 mV vs. Ag/AgCl revealed that the nanocrystalline Al had higher absolute currents. The scanning electron microscopy images showed that nanocrystalline Al surface was more corroding under the aggressiveness action of the seawater and the applied anodic potential value. This was also confirmed by the electrochemical impedance spectroscopy data, which indicated that the nanocrystalline Al shows lower polarization and solution resistances when compared to the microcrystalline Al. All results were in good agreement showing clearly that the nanocrystalline Al has less corrosion resistance and high corrosion rate in the Arabian Gulf seawater due to the presence of many active centers on its surface.
Corrosion Science, 2004
Electrochemical impedance technique has been applied to study the corrosion behavior of galvanized steel under wet-dry cyclic conditions with various drying periods. The wet-dry cycles were carried out for the period of 336 h by exposure to alternate conditions of 1 h immersion in a 0.5 M NaCl solution and drying for various time periods (11, 7 and 3 h) at 298 K and 60% RH. During the wet-dry cycles, the polarization resistance, R p , and solution resistance, R s , were continuously monitored. The instantaneous corrosion rate of the coating was estimated from the obtained R À1 p and time of wetness was determined from the R s values. The corrosion potential, E corr , was also measured only during the immersion period of each wet-dry cycle. In all cases, the corrosion was accelerated by the wet-dry cycles in the early stage, and started to decrease at a certain cycle and finally became similar to that at the initial cycle. The underlying steel corrosion commenced after the corrosion rate started to decrease. The shorter drying period in each cycle led to higher amount of corrosion of the coating because the surface was under wet conditions for longer periods. On the other hand, time to red rust appearance due to occurrence of the underlying steel corrosion became shorter as the drying period increased, although the total amount of corrosion was smaller. The corrosion mechanism of substrate steel under various drying conditions has been discussed, the galvanic coupling effect being taken into account.
CORROSION, 2009
Electrochemical impedance spectroscopy (EIS) is a powerful, rapid, and accurate nondestructive method for the evaluation of a wide range of materials. In this work, the corrosion behavior of some ferritic stainless steels was studied in 0.3 M hydrochloric acid (HCl) acid solution. The samples were obtained from casting and forging. Stainless steels were unalloyed and alloyed with about 1 wt% Ti, V, and Nb. The steels were exposed to different heat treatments, but heat treatment was not applied to the first group samples. The second and third group samples were rapidly cooled after annealing at 1,100°C for 30 min and 180 min, respectively. Corrosion resistance was calculated using the Stearn-Geary equation, and scanning electron microscopy (SEM) was performed. According to electrochemical impedance spectroscopy (EIS), the corrosion resistance increased by the alloying element. Heat treatment has a critical effect on the corrosion resistance. The best corrosion resistance was observed from ferritic stainless steel with Nb-exposed homogenization for 180 min.
Comparative study on the corrosion behavior of mild steel in effluents, sea and fresh water
Bayero Journal of Pure and Applied Sciences
The corrosion rate of mild steel behavior exposed to effluents (EF), sea water (SW) and fresh water (FW) were study using weight loss, scanning electron spectroscopy (SEM) and x-rays diffraction (XRD). The results show that the weight loss of mild steel in different water samples increases with increasing in immersion time and temperature respectively. The corrosion rate of water was found to be higher in sea water (0.003g cm2 week-2), effluents (0.021g cm-2 week-2) and fresh water (0.020g cm-2 week-2) respectively. The corrosion rate and behaviour of mild steel in the water sample were affected by some physical and chemical parameters such as pH, turbidity, conductivity and biological oxygen demand (BOD). Effluents (EF) were found to have pH (5.20), turbidity (13.3nut), conductivity (4203µs/cm) and BOD (0.119mg/dm3). Sea water (SW) were found to have pH (7.60), turbidity (173nut), conductivity (30800µs/cm) and BOD (0.028mg/dm3). Fresh water (FW) were found to have pH (7.60), turbid...
The electrochemical and corrosion behavior of austenitic stainless steel containing Cu
Corrosion Science, 1992
~The influence of Cu additions (0.4-3.0 wt%) on the electrochemical and corrosion behavior of 18-8 austenitic stainless steel was investigated. Both potentiodynamic polarization curves and potential decay curves, which were dependent upon the Cu content and the dissolved oxygen in the solution tested, were determined in both de-aerated and aerated 0.1 M H2SO 4 solution. Surface characterization was examined by Auger electron spectroscopy (AES) and X-ray photo-electron spectroscopy (XPS). Cyclic polarization curves determined in 3.5 wt% NaCI solution showed that the pitting protection potential (Epp) of the stainless steels tested increases with increasing Cu content. The constant extension rate test (CERT) in boiling 42 wt% MgC12 solution revealed that Cu had a detrimental effect on the stress corrosion cracking (SCC) resistance. The role of Cu on the corrosion behavior of the austenitic stainless steel observed in this investigation is discussed.
Journal of materials …, 2010
The electrochemical corrosion behavior of novel Cu-containing antibacterial austenitic and ferritic stainless steels in 0.05 mol/L NaCl solution has been investigated by dc polarization and ac impedance measurements and compared with that of the conventional stainless steels. Cu was found to particularly affect the kinetics of the anodic reaction. The corrosion performance of the austenite was greatly improved by Cu addition in the studied anodic potential range, whereas Cu effects on the ferrite showed remarkable sensitivity to the applied potential and improved corrosion resistance only in the low anodic potential range. Three-dimensional presentation of the variable-potential impedance data was employed in analyzing the electrochemical corrosion processes and revealed a close relationship between the impedance parameters and the applied potential. The trends of impedance results agree well with those obtained from potentiodynamic polarization measurements.
Metals
The effect of temperature, time and rotation speed of FT-GTL process water on the corrosion rate of API X-120 carbon steel was investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization techniques were used to determine the carbon steel corrosion rate under temperatures ranging from 293 to 323 K and rotation speed of 0, 500, 1000, 2000 rpm when the immersion time was 0.5, 1, and 2 h. The corrosion rate increased with temperature and rotation speed but decreased with immersion time. SEM, XRD, and XPS analyses of the corroded surfaces confirmed the formation of iron oxide and ferric oxide as the main components of the protective layer.