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W. Villamizar M. Casales J. G. Gonzalez-Rodriguez L. Martinez 《Journal of Solid State Electrochemistry》2007,11(5):619-629
The corrosion behavior of hydroxyethyl, amino ethyl and amid ethyl imidazolines corrosion inhibitors was evaluated by using
potenthiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy techniques.
Solutions included deaerated 3% NaCl, 3% NaCl+diesel saturated with CO2 at 50 °C with and without inhibitors. Regardless of the presence of diesel, the corrosion rate was decreased with the addition
of the inhibitors, but the time to reach a steady state was longer than when the oily part, i.e., diesel, was present. In
the absence of the oily part, the impedance results showed that the film formed was porous, allowing the electrolyte to diffuse
through it and corrode the metal. When the oily part was present, the film formed was much more stable, not porous, and did
not allow the electrolyte to corrode the sample. The most efficient inhibitor was the amid ethyl imidazoline, whereas the
least efficient was the hydroxyethyl imidazoline, because the film formed by the former was much more stable from the beginning
of the test. 相似文献
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Gonzalez-Rodriguez J. G. Casales M. Salinas-Bravo V. M. Espinosa-Medina M. A. Martinez-Villafañe A. 《Journal of Solid State Electrochemistry》2004,8(5):290-295
Electrochemical noise in current has been used to monitor the stress corrosion cracking (SCC) susceptibility of alloy 690 sensitized at 700 °C during 48 h in sodium thiosulfate at 90 °C. At 48 h of aging, the specimen failed by SCC and the corrosion current pulses had high intensity and low frequency, and were associated with the nucleation and propagation of stress corrosion cracks during slow strain rate tests. When the alloy was immune to SCC, the observed corrosion current pulses had a much higher frequency and lower intensity, indicating either uniform corrosion or passivation. The type of transients observed do not indicate the mechanism responsible for the observed embrittlement, but only the cracking initiation or propagation process. 相似文献
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D. M. Ortega-Sotelo J. G. Gonzalez-Rodriguez M. A. Neri-Flores M. Casales L. Martinez A. Martinez-Villafañe 《Journal of Solid State Electrochemistry》2011,15(9):1997-2004
The corrosion inhibition of X-70 pipeline steel in saltwater saturated with CO2 at 50 °C with carboxyamido imidazoline has been evaluated by using electrochemical techniques. Techniques included polarization
curves, linear polarization resistance, electrochemical impedance, and electrochemical noise measurements. Inhibitor concentrations
were 0, 1.6 × 10−5, 3.32 × 10−5, 8.1 × 10−5, 1.6 × 10−4, and 3.32 × 10−4 mol l−1. All techniques showed that the best corrosion inhibition was obtained by adding 8.1 × 10−5 mol l−1 of carboxyamido imidazoline. For inhibitor concentrations higher than 8.1 × 10−5 mol l−1 a desorption process occurs, and an explanation has been given for this phenomenon. 相似文献
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W. Villamizar M. Casales L. Martinez J. G. Chacon-Naca J. G. Gonzalez-Rodriguez 《Journal of Solid State Electrochemistry》2008,12(2):193-201
The corrosion inhibition of oleic, coconut, and stearic acid modified hydroxyethyl imidazolines on 1018 carbon steel was evaluated
by using potenthiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy
techniques. Solutions included deaerated CO2 saturated 3% NaCl with and without Diesel at 50 °C. Regardless of the presence of diesel, the corrosion rate was decreased
with the addition of the inhibitors, but the time to reach a steady state was longer than when the oily part, i.e., diesel,
was present. This was because the inhibitors are oil soluble, and with diesel, they are more easily transported towards the
metal surface. With diesel, the formed film seems to be more stable and protective, not allowing the electrolyte to corrode
the sample increasing the efficiency values up to 87 and 94%. The most efficient inhibitors were the coconut type fatty acid
hidroxyethyl imidazoline because the formed film was much more stable from the beginning of the test, whereas the least efficient
was the stearic acid modified hydroxyethyl imidazoline. 相似文献
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J. G. Gonzalez-Rodriguez I. Rosales M. Casales L. Martinez 《Journal of Solid State Electrochemistry》2005,9(10):691-697
The corrosion performance of Mo-22Si and Mo-25Si alloys in 0.5 M sodium chloride (NaCl) and 0.5 M sodium hydroxide (NaOH) solutions, at room temperature, was evaluated using electrochemical techniques. In 0.5 M NaCl, additionally, the effect of solution pH (3, 7 and 10) and concentration (0.1, 0.5 and 1.0 M) was studied using techniques such as potentiodynamic polarization curves, linear polarization resistance and electrochemical noise in current. The alloy contained either -Mo or Mo5Si3 phases in a Mo3Si matrix. Polarization results showed that only the alloys containing 22Si developed a passive film in 0.5 M NaOH solution, whereas the alloy containing 25Si was passivated only in 0.5 M NaCl, pH 10 solution. In 0.5 M NaCl, pH 7 and 0.5 M NaOH solutions, the alloy with 25Si was the one with the highest corrosion rate, whereas the one containing 22Si was the most corrosion resistant. In NaCl solutions, the alloys exhibited a localized type of corrosion, but not in NaOH solutions. Alkaline NaCl solutions increased the corrosion rate of the 75Mo-25Si alloy with respect to acidic or neutral solutions, whereas diluted (0.1 M) or concentrated (1.0 M) NaCl solutions produced lower corrosion rates than the 0.5 M NaCl solution. Some localized type of corrosion occurred in the NaCl solutions, due to a selective corrosion of the -Mo and Mo5Si3 phases with respect to the Mo3Si matrix. 相似文献
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