Estimation Of Corrosion Rate Research Articles

Long-term in situ performance of geopolymer, calcium aluminate and Portland cement-based materials exposed to microbially induced acid corrosion

This contribution presents an extensive performance evaluation of metakaolin-based geopolymer and calcium aluminate mortars during a long-term field exposure to a wastewater system exhibiting intensive microbially induced acid corrosion (MIAC) conditions. Results were compared to a high-performance OPC concrete, typically used for manhole fabrication. Field conditions were obtained by monitoring relative humidity, temperature, H2S and CO2. Microstructural degradation and elemental distributions within each binder type over time were recorded by electron probe microanalysis, X-ray diffraction and pH-imaging techniques, together with specimen's mass and surface-pH characterization. Microbiome and epifluorescence analyses indicated exposure-time dependent alternating bacterial community structures within the materials. Clear differences regarding bacterial species distribution and biodiversity were observed for the different binder types. Estimated corrosion rates were the lowest (1.4 mm/a) and the highest (13.3 mm/a) for the tested geopolymer formulations, pointing out that only well designed geopolymer materials may provide an improved MIAC resistance.

Corrosion Rate Optimization of Mild-Steel under Different Cooling Tower Working Parameters Using Taguchi Design

This study investigates the implementation of Taguchi design in the estimation of minimum corrosion rate of mild-steel in cooling tower that uses saline solution of different concentration. The experiments were set on the basis of Taguchi’s L16 orthogonal array. The runs were carried out under different condition such as inlet concentration of saline solution, temperature, and flowrate. The Signal-to- Noise ratio and ANOVA analysis were used to define the impact of cooling tower working conditions on the corrosion rate. A regression had been modelled and optimized to identify the optimum level for the working parameters that had been founded to be 13%NaCl, 35ᴼC, and 1 l/min. Also a confirmation run to establish the precision of the Taguchi design for optimization the corrosion rate in cooling tower with high reliability. The contour plot had been applied to understand how it can be in finding the relation between the corrosion rate and the working parameters of the cooling tower.

Investigation of Corrosion of 304 Stainless, Inconel 625, and Haynes 230 in a Chloride-Salt-Based Thermal Storage Medium

One of the critical challenges for latent heat thermal energy storage systems in concentrating solar power applications is corrosion of metallic alloys as containment and heat transfer fluid tube materials in corrosive salts at high temperatures. In this study, the effects of MgCl2 on the corrosion of stainless steel 304, Inconel 625, and Haynes 230 alloys were investigated through embedded metal samples in the graphite foam/MgCl2 storage medium. Four experimental testing modules were fabricated, and experimental tests were conducted under controlled environment by heating the testing modules to and keeping them at 750 °C for 100, 200, 500, and 1000 h. The estimated corrosion rates based on the weight losses for stainless steel 304, Inconel 625, and Haynes 230 were 94, 9, and 8 μm/year, respectively. The fitted equations for the loss of the thickness as functions of the exposure time show that the corrosion rates decrease with the exposure time. The results on the corrosion zones or depths and chromium segregation ranges of the experimental samples are also presented.

The origin of high hydrocarbon groundwater in shallow aquifer: experimental evidences from water-rock interaction.

The current studies had already revealed the hydrocarbons could migrate from relatively high hydrocarbon potential stratum to shallow groundwater by corrosion emission and extraction emission in karst area and further impact on human health. Then, the comprehensive experiments were used to understand the mechanism and process of hydrocarbon emission as a continuation of a long-term study on original high hydrocarbon groundwater in shallow Triassic aquifer, taking northwest Guizhou, China, as a reference. The results determined water-rock interaction that lead to the hydrocarbon emission into groundwater with salinity acting as the main driving force. Relatively high salinity promotes the rock corrosion and hydrocarbon emission in the study area. The hydrocarbon emission process varied with different strata, as the results show that the hydrocarbon uniformly distributed in T2g3 than that in T1yn4. Furthermore, the stratum with uniformly distributed hydrocarbon would likely contain high hydrocarbon groundwater, as determined by the process of sedimentation. In addition, "corrosion rate estimation method" and "mineral constituent estimation method" were firstly employed to estimate the hydrocarbon concentration in groundwater to date. Compared with the hydrocarbon concentration of local groundwater samples (0 to 0.14 mg L-1), the result of "mineral constituent estimation method" was analogous to measured value of groundwater samples in the area (0.05 to 0.50 mg L-1), indicating the concentration of hydrocarbon could be estimated by mineral constitutions of groundwater, which was related to the concentration of Ca2+ and Mg2+. Based on the methods and theories in this study, the concentration of original hydrocarbon in shallow groundwater could be estimated and help to understand the mechanism of water-rock interaction in shallow aquifer and original high hydrocarbon groundwater strategic assessment.

Reliability of the estimation of uniform corrosion rate of Q235B steel under simulated marine atmospheric conditions by electrochemical noise (EN) analyses

This paper aims to monitoring the atmospheric corrosion of Q235B steel by electrochemical noise (EN) technique, and both statistical parameters and frequency domain analysis are used to quantify the corrosion rate. The reliability of EN measurement was evaluated by electrochemical impedance spectroscopy (EIS). Experimental results indicate that electrolyte resistance have an impact on EN measurement but it can be discarded if it is much lower than the impedance of working electrode (WE). Theoretical predictions using Thevenin equivalent circuit model reveal that spectral noise impedance is not equal to impedance module as estimated by EIS, and a relationship between them is derived. Power spectral density (PSD) obtained from experimental data further verified the theoretical predictions.

Rebar Corrosion Rate Estimation of Reinforced Concrete Components Exposed to Marine Environment

Rebars embedded in reinforced concrete (RC) components were investigated. The rebar corrosion rate model is constructed to make macro quantitative evaluation and prediction of corrosion phenomena in RC components using regional marine environmental field exposure and laboratory accelerated corrosion method. The effect of the concrete strength and content of a mineral admixture on the rebar corrosion rate was studied by means of sampling corroded concrete components and measuring the rate of rebar corrosion under different exposure conditions. The mathematical model of the rebar corrosion rate in concrete components exposed to the marine environment is presented. Free chlorine ion contents on the rebar surface and rebar corrosion rates are linearly related.

Flow line corrosion failure as a function of operating temperature and CO2 partial pressure using real time field data

A Nonlinear Regression Analytical model was used to simulate the corrosion rate of CO2 flowing through a pipeline at different operating conditions. The model was formed by applying the simple current-resistance relationship which was further simplified to obtain an appropriate expression for estimating the corrosion rate of a pipeline in relation to the partial pressure of the gas at different temperatures (30–37 °C). Field conditions were validated against simulated results and based on the findings, the model proved to be an accurate tool for determining the corrosion rate of CO2 for curvilinear pipe of 3 km length transporting fluids having similar gas composition. Based on the estimated corrosion rates, the model's accuracy lies in the range of 96–99%. Also, from the results, there seem to be an approximate linear relationship/positive correlation between the corrosion rate of CO2 and, the system temperature and CO2 partial pressure.

A Method for Estimating Time-Dependent Corrosion Depth of Carbon and Weathering Steel Using an Atmospheric Corrosion Monitor Sensor.

In this study, a time-dependent corrosion depth estimation method using atmospheric corrosion monitor (ACM) sensor data to evaluate time-dependent corrosion behaviors is proposed. For the time-dependent corrosion depth estimation of uncoated carbon steel and weathering steel, acceleration corrosion tests were conducted in salt-spray corrosion environments and evaluated with a corrosion damage estimation method using ACM sensing data and corrosion loss data of the tested steel specimens. To estimate the time-dependent corrosion depth using corrosion current by an ACM sensor, the relationship between the mean corrosion depth calculated from the weight loss method and the corrosion current was evaluated. The mean corrosion depth was estimated by calculating the corrosion current and evaluating the relationship between the mean corrosion depth and corrosion current during the expected period. From the test and estimation results, the corrosion current demonstrated a good linear correlation with the mean corrosion depth of carbon steel and weathering. The calculated mean corrosion depth is nearly the same as that of the tested specimen, which can be well used to estimate corrosion rate for the uncoated carbon steel and weathering steel.

Corrosion Rate Estimation Based on Sensor Monitoring: Field Test Validation in Transmission Towers

A quantitative evaluation of corrosion rate was conducted by analyzing the data obtained from monitoring with galvanic sensors. Using humidity data, a new methodology was established to extract out...

A fresh look at depolarisation criteria for cathodic protection of steel reinforcement in concrete

Criteria for the successful application of cathodic protection (CP) for steel reinforced concrete have been fixed for decades and form part of ISO EN12696. The most used criterion is the achievement of 100 mV depolarization over a period not exceeding 24 hours after discontinuation of the applied current. Although more empirical than theoretically based, the criterion has served the CP industry well. It does, however, exclude any systems that may not always achieve that level of depolarization but have been shown to offer adequate protection, and so there is a need to explore ways of assessing depolarisation data more effectively. On a fundamental level, non-linear polarisation, as described by the Butler Volmer equation, relates corrosion rate to polarisation for a given applied current density and shows that at low current densities, estimated corrosion rates can be shown to be still insignificant at less than 100 mV polarisations. This paper explores the use of non-linear polarisation as an additional supportive criterion based on the measured 24-hour depolarisation level for a known applied current density and tests its applicability in the laboratory and in the field. It speculates that a reducing apparent corrosion current density trend in combination with a depolarised potential moving in a more noble direction is likely to be a suitable alternative criterion, where 100 mV depolarisation is not achieved.

Corrosion Rate Estimation in Steel Sheet Pile Walls - Comparison between Empirical Models and Eurocode 3, Part 5

Steel sheet pile wall corrosion in soils and water is a complex phenomenon. The deterioration of these structures is costly and difficult to predict. The aim of this paper was to deal some empirical corrosion models which are analyzed and compared to Eurocode 3, Part 5 to estimate corrosion rate and the loss of thickness of anchored steel sheet pile wall. The results show that care should be taken to ensure that the maximum bending moments do not occur at the same level as the main corrosion zones. Furthermore, it is possible to define an upper and a lower bound, corresponding respectively to the presence of sea water in low water and the undisturbed natural soils, in order to predict the loss of thickness due to corrosion.

Initial formation of corrosion products on pure zinc in saline solution

Corrosion product formed on zinc sample during 2 weeks immersion in saline solution has been investigated. The corrosion layer morphology as well as its chemical composition, was analyzed using scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Electrochemical measurement was used to analyze the corrosion behavior. Zinc oxide, zinc hydroxide and zinc hydroxide chloride were formed on zinc surface in saline solution. The thickness of corrosion layer increased with the time increased. The pure Zn has an estimated corrosion rate of 0.063 mm y−1 after immersion for 336 h. Probable mechanisms of zinc corrosion products formation are presented.

THE EFFECT OF ETHANOL ON FUEL TANK CORROSION RATE

In recent decades, the use of ethanol as an alternative fuel for S.I. engines has become a popular issue. This is not only due to availability and oil prices, but also to address concerns about the increase in greenhouse gas effects. However, ethanol is corrosive in a fuel tank made of metal, because it contains soluble chloride ions. Therefore, this paper presents the results of an investigation of the fuel tank corrosion rate made of metal Fe_U_100 due to the use of pure ethanol. The test was performed by PGS-120T potentiostat with the addition of NaCl in ethanol in concentrations of 5, 10, 15, 20, and 25% while the estimated corrosion rate on pure ethanol was done by regression. The estimation of the fuel tank corrosion rate through the exponential regression for the use of pure ethanol is 4,116 mpy. Then, from the assessment metrics, the fuel tank made of Fe_U_100 has corrosion resistance in the excellent category. This means no fuel tank modification or replacement is required for pure ethanol applications in S.I. engine.

A critical examination of corrosion rate measurement techniques applied to reinforcing steel in concrete

This paper presents an investigation of five corrosion‐monitoring techniques for reinforced concrete. The techniques studied are the potentiodynamic, galvanostatic, and coulostatic direct‐current techniques as well as electrochemical impedance spectroscopy (EIS), and the connectionless electrical pulse response analysis (CEPRA) technique. The study included monitoring corrosion rates on reinforced concrete specimens with a range of admixed chloride percentages, cover depths, and rebar diameters for 8 months. After this period, the rebars were extracted for mass loss measurements to determine the average corrosion rates. EIS was found to provide accurate measurements of active and passive corrosion rates with a simplified spectrum‐analysis procedure. Galvanostatic and potentiodynamic techniques were able to measure the corrosion rates for actively corroding reinforcements accurately, while the coulostatic technique overestimated it. For passive reinforcements, the coulostatic technique provided reliable corrosion rate estimates, while the potentiodynamic technique provided a minor overestimation, due to the fast scan rate used, and the galvanostatic technique failed in detecting passivity, due to the short measurement duration and confinement failure. Finally, the CEPRA technique provided accurate corrosion rate predictions except for passive rebars with small diameters embedded in saturated concrete.

Initial formation of corrosion products on pure zinc in simulated body fluid

Zinc was recently suggested to be a potential candidate material for degradable coronary artery stent. The corrosion behavior of pure zinc exposed to r-SBF up to 336 h was investigated by electrochemical measurements and immersion tests. The morphology and chemical composites of the corrosion products were investigated by scanning electron microscope, grazing-incidence X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. The results demonstrate that the initial corrosion products on the pure zinc mainly consist of zinc oxide/hydroxide and zinc/calcium phosphate compounds. The pure Zn encounters uniform corrosion with an estimated corrosion rate of 0.02–0.07 mm y−1 during the immersion, which suggests the suitability of pure Zn for biomedical applications.

Estimation of Corrosion Rate of Bulk and Powder Ni–Re Alloy

The corrosion current density of Ni–Re alloy (15.8 wt % Re) was estimated using recently developed method of compensating additives. The alloy was fabricated by the electrodeposition in the form of bulk specimen and the powder prepared of this specimen. The electrodeposition was performed in stirred 5 × 10–3 M HCl solution. The method enabled us to determine the corrosion rate with no external polarization of studied specimens and at virtually constant pH value. A specific electrochemical activity of powder surface was estimated by comparing the corrosion currents of bulk and powder specimens. The powder was intended for testing its catalytic activity in several electrochemical reactions.

A mathematical description accounting for the superfluous hydrogen evolution and the inductive behaviour observed during electrochemical measurements on magnesium

When electrochemical techniques are used to probe the surface of corroding magnesium with the aim of obtaining quantitative information on the corrosion process, two peculiarities are generally observed: i) with anodic polarization, the rate of hydrogen evolution increases instead of decreasing and ii) during electrochemical impedance spectroscopy measurements, an inductive contribution is often observed at the low-frequency end of the spectra. The presence of these two phenomena clearly has an impact on the methodology that should be applied to correctly estimate corrosion rates from electrochemical data. The aim of this work is to provide a general mathematical description of the corroding magnesium surface that, under minimal a priori assumptions regarding the reaction kinetics, can account simultaneously for both superfluous hydrogen evolution and inductive response. The mathematical results are consistent with the suggestion that the superfluous hydrogen evolution is mainly related to the increase of the surface of the active corrosion front during anodic polarization. Further, the obtained results show that the inductive response is expected when, at the corrosion front, oxidation of magnesium proceeds faster than hydrogen evolution.

Effect of uncertain factors on the hull girder ultimate vertical bending moment of bulk carriers

This paper focuses on the effect of initial imperfections and corrosion wastage on the age related strength degradation of bulk carriers. At the beginning, the initial imperfections including initial distortions and residual stresses, are employed to assess the ultimate bending moment reduction. Then, the effect of thickness degradation due to corrosion wastage on the ultimate hull girder strength is investigated. Finally, the combination of initial imperfections and corrosion wastage is considered to evaluate the residual hull girder strength. To do that, the initial imperfections of the unperfected structures and a corrosion rate estimation model for bulk carriers are introduced. A simplified method is also proposed to determine the ultimate vertical bending moment of ship hull girder subjected to initial imperfections and corrosion wastage. Additionally, the design and construction considerations for bulk carriers are made.

Расчет скорости коррозии и остаточного ресурса элементов трубопроводов АЭС по данным контроля

Расчет скорости коррозии и остаточного ресурса элементов трубопроводов АЭС по данным контроля

Accelerated estimation of corrosion rate in supercritical and ultra-supercritical water

This study explores a methodology for the determination of the accelerated corrosion rate of candidate materials to be used in advanced supercritical and ultra-supercritical water-based thermal reactors. Electrochemical impedance spectroscopy and electrochemical frequency modulation were used to evaluate the corrosion rates of SAE 316 stainless steel, Nitronic 50, Inconel 718, and Inconel 625 in supercritical water at 530 °C and in ultra-supercritical water at 600 °C. The results were compared to the results of gravimetric studies that were performed to determine the viability of the utilization of electrochemical analyses in supercritical and ultra-supercritical water. For all of the conditions that were tested, results showed that the corrosion rates during electrochemical testing had trends that were similar to the long-term gravimetric results. Thus, the hybrid methodology described in this manuscript can reduce testing times from >1000 h to ~ 10 h.