Carbon steels electrochemical behavior

Figure 33.2 shows results obtained by studies of electrochemical noise for the corrosion behavior of carbon steel A516-70 in carbonate solutions with and without NaCl as an activator (Cheng et al., 2000). It can be seen that in ordinary carbonate solution the fluctuations of potential of a test electrode and the fluctuations of current flowing between a pair of identical electrodes are small. Added NaCl causes a drastic increase in intensity of the electrochemical noise. The PDS plots (Fig. 33.3) differ accordingly. 

The electrochemical behavior of carbon dioxide under excessive pressure was investigated in a hermetically three-electrode cell made of special stainless steel, which permitted measurements at temperatures up to 900 °C and at an excessive gas pressure up to 2.0 MPa (Fig. 1). 

The results allowed a conclusion on the possibility of separate determination of metals and nitrotriazoles from the solution [987], The influence of nitrated 1,2,4-triazoles on corrosion and electrochemical behavior of low-carbon steels in aqueous solution of sodium sulfate has been investigated [988], The strong passivating action of nitrotriazoles on steel is caused by the formation of stable chemosorbed metal-azole films. 

Electrochemical potentlostat measurements have been performed for the corrosion of iron, carbon steel, and stainless steel alloys in supercritical water. The open circuit potential, the exchange or corrosion current density, and the transfer coefficients were determined for pressures and temperatures from ambient to supercritical water conditions. Corrosion current densities increased exponentially with temperature up to the critical point and then decreased with temperature above the critical point. A semi-empirical model is proposed for describing this phenomenon. Although the current density of iron exceeded that of 304 stainless steel by a factor of three at ambient conditions, the two were comparable at supercritical water conditions. The transfer coefficients did not vary with temperature and pressure while the open circuit potential relative to a silver-silver chloride electrode exhibited complicated behavior. 

Most of the data available in the literature are for subcritical conditions. Corrosion studies of iron alloys in supercritical water have not been reported. For supercritical fluid extraction and corrosion studies, a supercritical fluid reactor system for temperatures up to 530 C and pressures up to 300 atm was constructed. This system was used to determine the electrochemical behavior of type 304 stainless steel (304 S.S.), 316 S.S., 1080 carbon steel (1080 C.S.), and pure iron in supercritical water. 

I.V. Tsarenko, A.V. Makarevich and T.P. Kofman. Effect of nitro-derivatives of 1,2,4-trizole on corrosion-electrochemical behavior of low-carbon steel in aqua solutions of sodium sulfate. Electrochemistry, 1997, Vol. 33, No. 10, pp. 1177-1182. 

C. Xing, Z. Zhang, L. Yu, L. Zhang, G. A. Bowmaker, Electrochemical Corrosion Behavior of Carbon Steel Coated by Polyaniline Copolymers Micro/Nanostructures. RSCAdv. 2014,4,32718. 

Adhikari, A., Claesson, P., Pani,)., Leygraf, C., Deidinaitei, A., and Blomberg, E. (2008) Electrochemical behavior and anticorrosion properties of modified polyaniline dispersed in polyvinylacetate coating on carbon steel. Bectrochim. Acta, 53,4239-4247. 

Most poly pyrrole films have been prepared using inert electrodes, such as Pt [27], Au [28], or glassy carbon [29]. The main problem associated with the electrogeneration of polypyrrole onto active metals, such as Ti, Fe, stainless steel, or Al, is related to the interference of the electrochemical behavior of the metal with the... 

Y. Li, F. Wang and G. Liu (2004), Grain size effect on the electrochemical corrosion behavior of surface nanocrystallized low-carbon steel . Corrosion, 60 891-6. 

Liu, F.G. Du, M. Zhang, J, Qiu, M. (2009). Electrochemical behavior of Q235 steel in saltwater saturated with carbon dioxide based on new imidazoline derivative inhibitor. Corr. Sci, 2009, 51,102-109, ISSN 0010-938X. 

Using ordinary and sulfate-resistant Portland cement to represent differing chloride environments, short-term electrochemical monitoring and SEM were used to characterize corrosion behavior [34]. Steel electrodes attained passivity in mortar with high levels of calcium aluminate, up to 1% wt. chloride. At 1.75% wt. chloride, steel electrodes corrode. All chloride levels resulted in steel corrosion for low levels of calcium aluminate. Pore solution was also impacted by mortar exposure conditions. Atmosphere exposure had a high influence on hydroxide concentration in pore solution but no impact on chloride concentration. Carbonation was also investigated samples in a sealed container had a chloride/hydroxide ratio half that of unsealed samples. 

An important issue is the influence of an electrochemical environment on the cyclic deformation behavior of metals [74,33-35]. As illustrated by the data in Fig. 1 for a carbon-manganese steel in high-temperature water, environment does not typically affect the relationship between stresses and strains derived from the maximum tensile (or compressive) points of steady-state (saturation) hysteresis loops [36]. Such loops should relate to elastic and plastic deformation prior to substantial CF microcracking. CF data of the sort shown in Fig, 1 are produced by either stress or total strain controlled uniaxial fatigue experiments, identical to the methods... 

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