Advances of the analysis methodology for electrochemical noise in corrosion field were reviewed in this paper. Some examples of the analysis methodology, such as the direct current dirft, time-frequency analysis, non-linear analysis and pattern recognization, were introduced in order to demostrate the advantages and shortcomings of these analysis methodolgoies and finally, the development trend of the analysis methodology for electrochemical noise was also forecasted.

Alloys used for power station boilers need to meet simultaneously the requirements of the high temperature mechanical properties and corrosion resistance because of the harsh service environment. The purpose of this paper is to review the existing information regarding steam oxidation behavior and oxidation mechanism of alloys, which are used for the present power plant boiler and designed to be used in next generation power station.

As an important means to inhibit the atmosphere corrosion of metallic products, vapor phase corrosion inhibitors had attracted much attention, and on which the research was made great progress recently. In this paper the development of the vapor phase corrosion inhibitors was reviewed in terms of the classification, properties, evaluation methods and inhibition mechanism. The development trend of the corrosion inhibitors has been prospected.

The structural materials used in light water reactors (LWR) such as nickel based alloys and stainless steels have been found to be susceptible to stress corrosion cracking (SCC) in high temperature water. In this review, we summarized the research progress and current status on SCC of the structural materials used in LWR in terms of experimental methods, factors influencing SCC and the mechanisms of SCC. The research hotspots like the influence of cold-working and the SCC of weld joints were discussed. Some of the challenges and perspectives for the research of SCC in the future were also briefly addressed.

Electrochemical characteristics and stress corrosion cracking (SCC) behavior of 13Cr stainless steel were investigated by electrochemical measurements, U-bent specimen immersion test and surface analysis technique in an artificial solution with an autoclave, which aimed to simulate the annulus environment around CO₂ injection well. The results showed that annulus solution around injection well was a complicated H₂S-CO₂-Cl^- environment which generated the SCC of 13Cr stainless steel. The pitting breakthrough potential and SCC resistance of 13Cr stainless steel decreased obviously with increasing H₂S partial pressure, which is associated with the deterioration of surface film (passive film and corrosion products scales) on the steel. When the H₂S partial pressure exceeded 0.20 MPa (including 0.20), SCC occurred on 13Cr steel. Typical transgranular and intergranular fracture morphologies were observed, which indicated that the SCC process was mixed-controlled by both anodic dissolution and hydrogen-induced cracking.

The corrosion behavior of P265GH low alloy steel and Q235 carbon steel under dry/humid/immersion alternative condition with NaCl and NaHSO₃ were investigated by SEM, XRD, FTIR and mass loss analysis. The results show that, the relationship of mass loss to test time for the two steels fits to the same dynamics law. The corrosion products contain a large amount of dense α-FeOOH and amorphous δ-FeOOH. The resistance of rust layer make corrosion rate of the two steels decrease. The mass loss of the two steels is almost the same in the beginning stage, the difference of the mass loss become large with test time. The P265GH low alloy steel exhibited lower mass loss, denser rust layer, and better corrosion resistance rather than Q235 carbon steel.

The stress corrosion behavior of the weld seam and base metal of 16MnR steel in solution of HNO₃-H₂SO₄-H₂O, one of the typical environments of FCCU regenerator, was investigated using U-bend specimen immersion test and electrochemical polarization curves. The results show that the weld seam of 16MnR is more sensitive to nitrate stress corrosion cracking than base metal, its mechanism is anodic dissolution. Both the introduction of sulfate and the slightly reduction of pH can destroy the protective film on 16MnR steel, and increase the corrosion susceptibility of its weld seam. However, when the pH of solution is less than 2, the material is in active state, resulting in a serious of uniform corrosion. Besides the effective methods to slow down the stress corrosion of materials in catalytic cracking regenerator are analyzed in this article.

The corrosion behavior of continuous casting copper-clad steel in Dagang soil with 20%~30% water contents was studied by polarization curve measurement and EIS. It is shown that during the initial corrosion stage, the corrosion rates of continuous casting copper-clad steel are almost equal, which imply the water contents have little influence on the corrosion behavior. The control step for corrosion of continuous casting copper-clad steel in the soil is activation polarization process at the initial stage. During the later stage, the corrosion rates of continuous casting copper-clad steel decrease and then tend to be stable with the increase of water contents, which may be due to the synergistic effect of the two opposite factors i.e. the block effect with reducing oxygen and the stimulation effect with environmental water on the electrode process. However the corrosion behavior is mainly affected by oxygen diffusion control.

选择Cu-P-Cr-Ni钢、Cu-P-Cr钢和Q235碳钢,在0.01 mol/L的NaHSO₃溶液中进行周期浸润、阻抗谱和极化曲线实验,研究了Cu-P-Cr-Ni系合金钢相比Q235碳钢在模拟工业大气 (SO₂) 环境下的耐腐蚀性能；利用SEM, EPMA面扫描和XRD分析腐蚀锈层的形貌、组成及Cu,Cr和Ni的元素分布情况。结果表明：Cu-P-Cr-Ni系钢的腐蚀诱发敏感性最低,其次为Cu-P-Cr钢,腐蚀速率分别为Q235碳钢的59.5%和52.8%；锈层分为内、外两层,致密的内锈层明显发生Cu的颗粒状、Cr的团聚状富集,外锈层主要有Cr的富集,Ni富集不明显。Cu和Cr等的富集可形成致密的内锈层,提高低碳钢的耐蚀性。

A comprehensive brightening solution was developed for pretreatment of iron and steel parts before coatings application. The brightening solution can act as agent for simultaneous removal oil or rust on and phosphatization of the steel surface. The solution is free from F^-, NO^2-, Cr³⁺ and other toxic ions, thereby environmental friendly. The steel parts can be easily pretreated by wiping with or dipping in the solution at ambient temperature. The surface and cross sectional morphology of phosphating film was observed by OM and the corrosion resistance of the film was also examined. It showed that the phosphating films formed on the steel surface is dense, thin and uniform, with excellent corrosion resistance. Coatings can be applied directly on the phosphatized steels.

The formation of rusts consisted mainly of malachite on bronze was simulated with a new process, by which the corrosion test of bronze samples was performed in controllable environments with excess of CO₂ contents, water vapor and chlorine ions. The chemical composition, microstructure and phase constituents of the corrosion products were characterized by means of optical microscopy, scanning electron microscope (SEM) with energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and Raman microscopy. The results revealed that the characteristics of corrosion products were related with the content of CO₂ and H₂O in the environment. The growth mechanism of the rusts in these environments was discussed and the suggestions for preservation of the ancient bronzes were proposed.

The cathodic reduction process of Zn in alkaline zincate electrolyte was studied by cyclic<br>voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS), while the electrochemical nucleation behavior of Zn was also characterized by using chronoamperometry (CA) and scanning electron microscope (SEM) techniques. The results indicated that Zn existed in the electrolyte in the form of Zn(OH)₄^2-, through a preceding reaction which then transformed into Zn(OH)₂ during electrodepositing. As the species directly discharged on the cathode surface, the discharge of Zn(OH)₂ is a two step-process, by the first step Zn(OH)_ad was produced and adsorbed on the surface of cathode, and then was reduced to Zn by the second step. The two steps of reduction of Zn(OH)₂ were all nonreversible reaction. It is beneficial to the electrodeposition of Zn when the applied potential reduces. The first discharge reaction of Zn(OH)₂ occurred when the applied potential was at -1.40~-1.50 V. The two discharge reactions of Zn(OH)₂ were both occurred in the alkaline zincate system when applied potential reduced to -1.60 V but in this case, Zn atoms only adsorbed on the cathode surface and the electrodeposition process was in a non-steady state. The adsorbed Zn could finally electrocrystallized to form a uniform Zn coating only when the applied potential reduces to -1.70~-1.80 V. The electrocrystallization of Zn from alkaline zincate electrolyte may follow a three-dimensional progressive nucleation mechanism.

Concrete slab as a part of marine engineering structure should surly be suffered from chloride ions corrosion. The relevant chloride ions diffusion problem in a concrete slab immersed in seawater was solved by means of separation variable method in this paper. In comparison with the solutions obtained by error function and numerical calculation methods, we proved this generalized solution was the correct answer for the bilateral chloride ion diffusion in a concrete slab. According to calculation and analysis, we found that the bilateral diffusion would cause greater harm than one side diffusion, but concentration superposition would not occur; chloride ion diffusion rate would speed up when concentration gradient increase caused by the increasing chloride ion concentration at one side surface. A mutation of chloride ion concentration gradient might occur where diffusion coefficient changed, but the chloride ion concentration distribution kept continuous.