Corrosion Monitoring Methods Research Articles

The Use of AC and DC Methods for Corrosion Monitoring of Reinforced Concrete Members in Marine Environment

The Use of AC and DC Methods for Corrosion Monitoring of Reinforced Concrete Members in Marine Environment

Methods for studying corrosion in reinforced concrete

This Paper reviews available techniques for monitoring steel corrosion in reinforced concrete. Electrochemical techniques are by far the most suitable for this purpose, and meet most of the requirements. me responses of direct and alternating current corrosion monitoring methods for steel–concrete systems are compared under two extreme conditions, i.e. steel being corroded in the active state and in the passive state. Most practical situations will belong to one of these or be intermediate to them. Results of polarization resistance measurements (taken by applying a potential step, a current step and small-amplitude cyclovoltammetry), a coulostatic method and electrochemical impedance spectroscopy are reported. It is shown that metal polarization resistance in particular, and electrochemical methods in general, can provide fast and reliable information on the corrosion rate of steel in concrete, suflciently accurate to distinguish between acceptable and unacceptable conditions in most scientific and technical applications.

Potential transmission and transients during corrosion: Applications to corrosion monitoring

The transmission of potential along a passive metal/electrolyte interface, which is important in corrosion monitoring, has been considered for transitory and sustained corrosion processes. The observed signals are modified and delayed by the passive surface. Analysis, based on a transmission line as the equivalent circuit of a pipe and the impedance characteristics of the passive-metal-solution interface, allows the effectiveness of corrosion monitoring methods to be considered.

Qualitative corrosion monitoring by on-line ion chromatography

The corrosion mechanism for secondary side systems of pressurized water reactors has always been difficult to monitor and quantify. Ion chromatography may be the method to evaluate the corrosion phenomena using on-line systems. Two separate ion chromatography methods have been developed to monitor manganese, a component of carbon steel and stainless steel used in secondary system piping. The first method employs step gradient cation-exchange separation with chemically suppressed conductometric detection. The second method employs traditional transition metal analysis using an analytical column followed by post-column reagent addition and mixing with visible detection at 520 nm. The presence of manganese was verified using corrosion product monitors. Each monitor has a 0.45-μm particulate filter followed by three cation-exchange membrane filters for the determination of soluble metallic species. Atomic absorption spectrophotometry was employed to analyze the processed filters. Results for the corrosion monitors and the ion chromatography methods were compared to attempt validation of all methods and to establish practical methods for on-line corrosion monitoring.

Determination of Corrosion Properties of Lacquered Tinplate in Citrate Solutions by DC and AC Electrochemical Methods

Abstract The present investigation has been carried out to determine the usefulness of direct current (DC) and alternating current (AC) electrochemical methods for corrosion monitoring of unlacquered and lacquered tinplate samples. Evaluation was performed with 5-µm and 7-µm coatings of an epoxy-phenolic lacquer in citrate buffer solution, pH=4. The steady-state corrosion conditions for these epoxy-phenolic lacquers were established after 8 to 10 days of accelerated corrosion at 37°C. Electrochemical impedance spectroscopy (EIS) was used to obtain Rp in the Stern-Geary equation. The data indicate that the corrosion rate in the cans is completely due to the tin dissolution process. For the electrolytes chosen for this study, the iron content of the solution was found to be very low. lcorr values were obtained by DC and AC methods and the results agreed well.

６０Ｈｚリサジュー図によるステンレス鋼の孔食腐食速度の測定

A corrosion monitoring method is proposed using electrochemical techniques based on AC impedance theory. Monitoring corrosion rates by the AC impedance method with a low frequency response is time consuming. A method of monitoring to obtain corrosion rates easily by using a Lissajous figure technique with 60Hz commercial frequency was applied to pitting corrosion of SUS304 stainless steel in a neutral sodium chloride solution. The value of tanθ calculated from the inclination angle θ of the Lissajous figure was found to be related to pitting current density I at an impedance Z>1 bytanθ=K·I K: const.The relation between the value of tan θ and the corrosion rate was discussed in terms of reaction processes of charge transfer and diffusion.

交流インピーダンスとフーリエ積分に基づく腐食モニタリング法

交流インピーダンスとフーリエ積分に基づく腐食モニタリング法

内燃機関冷却水系統

内燃機関冷却水系統