Corrosion Kinetics Of Steel Research Articles

Effects of turbulent flow on the corrosion kinetics of X52 pipeline steel in aqueous solutions containing H2S

AbstractThis work presents the electrochemical results obtained during the study of the corrosion of X52 pipeline steel sample, immersed in brines containing H2S, under turbulent flow conditions. Linear polarisation resistance (LPR), electrochemical impedance spectroscopy (EIS), Electrochemical Noise (EN) and polarisation curves were used in order to determine the effect of turbulent flow upon the corrosion kinetics of the steel. It was found that flow has a considerable influence upon the electrochemical process occurring on the surface of the steel and the corrosion rate is increased.

The kinetics of steel corrosion in sea water

The kinetics of corrosion damage accumulation in stainless steels of various systems was studied using samples exposed in a model aqueous NaCl solution and in sea water. The time variation of the degree of corrosion damage corresponds to a reaction of the first order. The values of the corrosion activation energy and a parameter characterizing protective properties of a protective film on the metal surface are determined.

Behaviour of steel reinforcement under the effect of strong cathodic or anodic polarizations

The behaviour of highly polarized steel embedded in concrete was analysed using small mortar specimens and concrete beams, as well as slabs of considerable size, in the presence and absence of chloride additions. Electrochemical impedance spectroscopy (EIS) was used for the small samples, and polarization resistance was measured in the large ones. The measurements at corrosion potential provide information about the corrosion kinetics of steel embedded in concrete. The response under high cathodic polarizations provides information about the behaviour of the electrodes subjected to cathodic protection or forming galvanic macro-cells with highly electronegative metals. The response under high anodic polarizations can provide information about the behaviour of reinforcements exposed to erratic currents, or about the effect of galvanic macro-cells with metals much nobler than steel.

Effects of Moisture Availability on Corrosion Kinetics of Steel Embedded in Concrete

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.

Technical Review of 100 mV Polarization Shift Criterion for Reinforcing Steel in Concrete

Abstract Criteria for effective cathodic protection of steel-reinforced concrete (SRC) structures presently in use were adopted from underground applications. Their applicability has been subject to considerable discussion. The two most frequently used criteria are the E log I and 100 mV polarization shift tests. To mitigate corrosion of reinforcing steel effectively, the use of valid cathodic protection criteria is extremely important. In this paper, an analysis of 100 mV polarization shift criteria for SRC is made based on the corrosion kinetics of steel in concrete and chemical and physical properties of concrete.

Factors affecting the corrosion rate of steel in carbonated mortars

The corrosion of steel in carbonated mortar has been investigated by monitoring polarization resistance, corrosion potential and mortar resistivity. The results suggest that factors such as relative humidity and chloride contamination affect the corrosion rate via their influence on mortar resistivity. To account for the observed electrochemical relationships, most notably the linear correlation between corrosion rate and conductivity, and the exponential increase in corrosion rate with fall in corrosion potential, it is proposed that the corrosion kinetics of steel in carbonated mortar are subject to anodic control with the anodic reaction rate being limited by the resistance of the mortar. In this model, termed anodic resistance control, resistivity is viewed as a factor which may limit a half reaction rate in a similar way to diffusion and activation polarization. It is also shown that, when such a model is operating, the use of polarization resistance to monitor corrosion rate changes may still be justified provided the cathodic reaction rate is an exponential function of potential.