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The purpose of this study is to investigate the effect of Y₂O₃ mass fraction on the electrochemical corrosion performance of CrNi coating, which provided a foundation for the performance optimization of CrNi coatings.

CrNi coatings with the different Y₂O₃ mass fractions were fabricated on AISI H13 steel by laser cladding, and the effect of Y₂O₃ mass fraction on the electrochemical performance of CrNi coating in 3.5% NaCl solution was investigated using an electrochemical workstation.

The electrochemical corrosion performance of CrNi coating enhances with the increase of Y₂O₃ mass fraction, and the CrNi–15%Y₂O₃ coating has the largest polarization resistance and the lowest corrosion current density, which displays the best electrochemical performance among the CrNi–5%Y₂O₃, –10%Y₂O₃ and –15%Y₂O₃ coatings. The protective films are formed with the increase of Y₂O₃ mass fraction, which inhibits the occurrence of electrochemical corrosion.

The Y₂O₃ was first added to the CrNi coating to improve its electrochemical corrosion performance, and the influence of Y₂O₃ on the corrosion resistance of the CrNi coating was discussed by the corrosion model.

To provide a summary of research work carried out mainly in the authors' group for evaluating various protective coatings including rustproofing oils, and also for studying corrosion inhibitors using the wire beam electrode (WBE) method.

A range of published papers published during the past 15 years was summarised and reviewed. Recent research work in the authors' group was also included, which involved the combined use of the WBE with electrochemical noise analysis and the scanning reference electrode technique.

The WBE method has been developed into a very useful tool of evaluating the performance of coatings and inhibitors. In particular, The WBE is uniquely applicable for determining the performance of coatings and inhibitors to control localised corrosion.

Focusing mainly on recent research.

A useful source of information for researchers and graduate students working in the areas of organic coating and inhibitor research.

The first summary or review on this research topic.

This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a guiding significance on the corrosion resistance of H13 hot work mould steel.

A WC–12Co coating was fabricated on H13 hot work mould steel using a HVOF, and the electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution was measured using open circuit potential (OCP), potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) tests.

The OCP and PPC of WC–12Co coating positively shift than those of substrate, its corrosion tendency and corrosion rate decrease to enhance its corrosion resistance. The curvature radius of capacitance curve on the WC–12Co coating is larger than that on the substrate, and the impedance and polarization resistance of WC–12Co coating increase faster than those of substrate, which reduces the corrosion process.

The electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution is first measured using OCP, PPC and EIS tests, which improve the electrochemical corrosion resistance of H13 hot work mould steel.

The purpose of this paper is to investigate the effects of laser power on the electrochemical corrosion performance in 3.5% NaCl, 0.1 M H₂SO₄ and 0.1 M NaOH solutions, which provided an experimental basis for the application of Al–Ti–Ni amorphous coating in marine environment.

Amorphous Al–Ti–Ni coatings were fabricated on S355 structural steel by laser thermal spraying (LTS) at different laser powers. The surface and cross-section morphologies, chemical element distribution, phases and crystallization behaviors of obtained coatings were analyzed using a scanning electron microscope, energy-dispersive X-ray spectroscope, X-ray diffraction and differential scanning calorimetry, respectively. The effects of laser power on the electrochemical corrosion performances of Al–Ti–Ni coatings in 3.5% NaCl, 0.1 M H₂SO₄ and 0.1 M NaOH solutions were investigated using an electrochemical workstation.

The crystallization temperature of Al–Ti–Ni coatings fabricated at the laser power of 1,300 and 1,700 W is ∼520°C, whereas that fabricated at the laser power of 1,500 W is ∼310°C. The coatings display excellent corrosion resistance in 3.5% NaCl and 0.1 M NaOH solutions, while a faster dissolution rate in 0.1 M H₂SO₄ solution. The coatings fabricated at the laser power of 1,300 and 1,700 W present the better electrochemical corrosion resistance in 3.5% NaCl and 0.1 M NaOH solutions, whereas that fabricated at the laser power of 1,500 W exhibits the better electrochemical corrosion resistance in 0.1 M H₂SO₄ solution.

In this work, Al-wire-cored Ti–Ni powder was first on S355 steel with the laser power of 1,300, 1,500 and 1,700 W, and the effects of laser power on the electrochemical corrosion performance in 3.5% NaCl, 0.1 M H₂SO₄ and 0.1 M NaOH solutions were investigated using an electrochemical workstation.

The purpose of this paper is to investigate, the effects of residual stress and microstructure on the corrosion behaviour of carburised 18CrNiMo7-6 steel in a 3.5% NaCl aqueous solution.

The electrochemical tests were conducted using an electrochemical workstation with a three-electrode system in a 3.5% NaCl aqueous solution, the residual stress of each working face was measured by a high-speed residual stress analyser, and microstructure of different carburised layers were observed scanning electron microscopy. Finally, the effect of carbon content, microstructure and residual stress on the corrosion behaviour of the steel was discussed.

The results showed that the residual compressive stress in the carburised layer initially increased and subsequently decreased with increasing depth of the carburised layer, reaching stability in the matrix layer. The electrochemical tests before and after stress reduction showed that the electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress.

The residual compressive stress in the carburised layer initially increases and subsequently decreases with increasing carburised layer depth. The electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress. The general relationship between electrochemical potential and residual stress was established.

The purpose of this paper is to identify corrosion types and corrosion transitions by a novel electrochemical noise analysis method based on Adaboost.

The corrosion behavior of Q235 steel was investigated in typical passivation, uniform corrosion and pitting solution by electrochemical noise. Nine feature parameters were extracted from the electrochemical noise data based on statistical analysis and shot noise theory. The feature parameters were analysis by Adaboost to train model and identify corrosion types. The trained Adaboost model was used to identify corrosion type transitions.

Adaboost algorithm can accurately identify the corrosion type, and the accuracy rate is 99.25%. The identification results of Adaboost for the corrosion type are consistent with corroded morphology analysis. Compared with other machine learning, Adaboost can identify corrosion types more accurately. For corrosion type transition, Adaboost can effectively identify the transition from passivation to uniform corrosion and from passivation to pitting corrosion consistent with corroded morphology analysis.

Adaboost is a suitable method for prediction of corrosion type and transitions. Adaboost can establish the classification model of metal corrosion, which can more conveniently and accurately explore the corrosion types. Adaboost provides important reference for corrosion prediction and protection.

The purpose of this paper is to report a novel electrochemical sensor designed to detect the corrosion of metal cans used for beverage packaging.

Electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were performed to detect the corrosion degree of beverage cans that had been stored for 1 month (named s1), 3 months (named s2), 27 months (named s3) and 43 months (named s4).

The EIS results showed that the EIS plot of s1 samples had not developed to a characteristic of two time‐constants, indicating that the coating showed good protective performance. The EIS plots of s2, s3 and s4 showed characteristics of two time‐constants, indicating that the organic coatings of s2, s3, and s4 had lost their protective performance. EN results showed that quantities and amplitudes of transient peaks increased with the increasing storage time, indicating that an increasing degree of local corrosion occurred within the cans. A corrosion process for beverage cans is discussed and can be considered in three stages.

The designed electrochemical sensor was successfully applied to detect the performance of beverage cans and, further, provided scientific proof to evaluate the shelf life of metal cans for packaging.

The purpose of this paper is to present a novel five‐electrode electrochemical corrosion sensor. Health degradation by the corrosion of steel in civil engineering is a persistent problem. Structural health monitoring (SHM) techniques, including embedded sensors, can greatly improve the quantification of the steel corrosion information, which can lead to promote assessments of structural safety and serviceability. To integrate the corrosion monitoring system in future, the corrosion sensor and the monitoring methods have been explored here in advance. Also, the corrosion monitoring system has been applied preliminarily in the investigation of reinforcing concrete (RC) beams.

First, a novel five‐electrode electrochemical corrosion sensor has been developed as the hardware to provide the platform for corrosion monitoring methods. Second, half‐cell potential of the RC beams has been measured before and after corrosion. Third, galvanostatic step method has been used to excite the steel‐concrete system, and the transient response of the system has been obtained and analyzed. Finally, wavelet transform algorithm has been established to analyze the electrochemical noise (EN) data of the steel bars in RC beams.

The results show that the corrosion sensor can be used effectively as the hardware to support the electrochemical measuring techniques. Much valuable information which is extracted by analyzing the potential response to the galvanostatic pulse excitation can be applied to determine the general corrosion state of the reinforcing steel. For pitting corrosion, the energy distribution plot of EN can be adopted as a benchmark method to identify the presence of the corrosion pit.

The paper provides the key techniques for a SHM system to realize corrosion monitoring of large‐scale RC structures in the future.

The purpose of this paper is to compare electrochemical corrosion characteristics of conventional and unconventional fluoride conversion coating prepared on magnesium alloy.

The chemical reaction of AZ61 with 38 wt.% hydrofluoric acid (HF) for 24 h was used as a conventional way of fluoride conversion coating preparation. The unconventionally prepared coating was created in Na[BF₄] salt melt at 450°C for 2 h. Morphology and chemical composition of prepared fluoride conversion coatings were studied with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Electrochemical corrosion characteristics of the coatings were analyzed in Hank’s solution using potentiodynamic tests.

Both the coating preparation ways resulted in the creation of uniform conversion coatings with the same thickness (1.3 ± 0.1 μm). Some defects were observed on the coatings surface; however, the defects did not reach the AZ61 surface. Electrochemical tests performed in Hank’s solution at 37°C showed an improvement of corrosion resistance of AZ61 treated with fluoride conversion coatings when compared to the untreated material. Unconventionally prepared coating reached better electrochemical corrosion characteristics when compared to the conventionally prepared coating.

Electrochemical corrosion characteristics of AZ61 magnesium alloy can be improved with fluoride conversion coatings. Two methods are used in the literature for the coatings preparation. The conventional method is based on dipping of the coated material to the HF, and the unconventional method lies in dipping of the sample to the Na[BF₄] salt melt. The main purpose of the present study is to analyze the conventionally and unconventionally prepared coatings in terms of chemical analysis, morphology and material corrosion protection (electrochemical corrosion characteristics), while the data are not provided in the literature, according to the authors’ knowledge. Very similar coatings were prepared using both the methods from the morphological and chemical composition point of view. However, unconventionally prepared coating created in Na[BF₄] salt melt reached better electrochemical corrosion characteristics compared to the coating prepared in HF.

The purpose of this investigation was to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in seawater (flow velocity from 0 to 0.8 m/s, sediment content from 0 to 0.15 percent), to analyze the effects of the flow velocity and sediment content on the erosion-corrosion process.

A simulated erosion-corrosion test system was set up. Weight loss determinations and electrochemical measurements (such as potentiostat square wave (PSW), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests) were used to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in stagnant and flowing seawater with different sediment contents.

Under the test conditions, ZHMn55-3-1 copper alloys had good corrosion resistance to stagnant clear seawater, while increasing the flow velocity and sediment content reduced the corrosion resistance of the material. The difference in the erosion-corrosion mechanism between flow velocity and sediment content was that the former affected both the cathode process and the anode process of electrochemical corrosion, while the latter essentially affected only the anode process.

This paper explains the effects of flow velocity and sediment content on the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in flowing seawater.