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This paper aims to study the use of electrochemical noise (EN) technology in the corrosion continuous monitoring of stainless steel (SS) in an atmospheric environment.

An EN electrode was designed and fabricated to acquire the EN of 304 SS in the atmospheric environment. The statistical analysis and shot noise analysis were used to analyze the EN, and the surface morphology analysis of 304 SS was used to verify the EN analysis results.

The activation state, passive film formation and pitting corrosion of 304 SS can be clearly distinguished by the amplitude and frequency change of EN. The metastable pitting corrosion and steady-state pitting corrosion can be identified with the shot noise parameters q and fn. Under the existence of chloride ion, the stability of 304 SS passive film decreases and the steady-state corrosion pits of 304 SS are more likely to form with the reduction of thin electronic layer (TEL) pH. The critical TEL pH of 304 SS corrosion is a pH between 3 and 4.

In an atmospheric environment, the EN technology was used in the corrosion continuous monitoring of SS.

The aim of this paper is to construct a device that simulated the seawater splash zone, dynamic waterline zone (splash zone) and full immersion zone. Localized corrosion of 2A12 aluminum alloy long-scale specimen was studied.

Corrosion morphologies before and after the corrosion product removal were used to identify corrosion intensity at full seawater immersion zone, dynamic waterline zone (splash zone) and atmospheric zone. The average depth and diameter of corrosion pits in the three zones were evaluated by three-dimensional optical microscopy. The impact of wetting time of the atmospheric zone on the localized corrosion was investigated.

Corrosion pits were observed on the surface on day 4 for the wetted atmospheric zone (Case 1), and on the surface on day 8 for the alternant wet/dry atmospheric zone (Case 2). The corrosion product layer on the surface for Case 1 was partially broken down while the layer on the surface for Case 2 was intact. Average pitting depth and pitting diameters for Case 1 were more serious than that for Case 2.

The above findings revealed that the humidity of the atmospheric zone had great impact on the localized corrosion of aluminum alloy at the seawater splash zone.

Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted to investigate the influence of freeze-thaw cycles on the rebar corrosion in reinforced concrete. The purpose of this paper is to provide fundamental information about rebar corrosion under frost environment and improvement measures.

The related elastic modulus and compressive strength of different concrete specimens were measured after different freeze-thaw cycles. The accelerated rebar corrosion test was carried out after different freeze-thaw cycles; additionally, the value of calomel half-cell potential was determined. The actual rebar corrosion appearance was checked to prove the accuracy of the results of calomel half-cell potential.

The results show that frost damage aggravates the rebar corrosion rate and degree under freeze-thaw environment; furthermore, the results become more obvious with the freeze-thaw cycles increasing. Mixing the air-entrained agent into fresh concrete to prepare air-entrained concrete, increasing the cover thickness and processing the surface of concrete with a waterproofing agent can significantly improve the resistance to rebar corrosion. From the actual appearance of rebar corrosion, the results of calomel half-cell potential can well reflect the actual rebar corrosion in reinforced concrete.

The durability of reinforced concrete is mainly determined on chloride penetration that brings about rebar corrosion in chloride environments. Furthermore, the degradation of concrete durability becomes more serious in the harsh environment. As the concrete exposure to the freeze-thaw cycles environment, the freeze-thaw cycles accelerate the concrete damage, and the penetration of chloride into the concrete becomes easier because of the growing pore and crack sizes. In addition, rebar corrosion caused by chloride is one of the major forms of environmental attack on reinforced concrete. The tests conducted in this paper will describe the rebar corrosion in reinforced concrete under freeze-thaw environment.

The purpose of this paper is to investigate the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

Al₂O₃ particles and 10 wt% NaCl solution are used to evaluate erosion and corrosion resistance of WC-Ni vacuum brazed coating. Combined test of erosion and corrosion is also conducted. The microstructure of each specimen is characterized by the scanning electron microscopy. The chemical composition was determined by energy-dispersive X-ray spectroscopy.

WC-Ni vacuum brazed coating layer is effective protective coating under combined erosion and corrosion environment. The weight loss of coating layer is more reduced as the cumulative test time.

WC-Ni vacuum brazed coatings are investigated to check characteristic of the combined erosion and corrosion environment. WC-Ni vacuum brazed coatings are kind of diffusion coating that attract attention because of the resistance of superb impact and corrosion in comparison with other coatings. Some previous researches reported the properties of vacuum brazed WC material. Erosion and corrosion behaviors of WC-Ni vacuum brazed coatings were studied in our previous research, respectively. Hence, in this research, the principal objective is to examine the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

The purpose of this paper is to investigate the effect of welding procedure on the corrosion behaviors of weathering steel 09CuPCrNi in marine atmospheric environment. The corrosion processes of weathering steel 09CuPCrNi and its welded joints in marine atmospheric environment were simulated by a salt spray dry-wet test.

The corrosion behaviors of the base metal and the welded joints at corrosion times of 2, 4, 8, 12, 24 weeks were investigated by weight loss test, electrochemical techniques, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). The corrosion rates, as well as the morphologies and electrochemical characteristics of corrosion products, the distribution of major alloying elements in rust layer were obtained. The influence of welding on the atmospheric corrosion of 09CuPCrNi was studied.

The results indicate that the corrosion rate of the 09CuPCrNi welded joints decreases gradually with the corrosion time, and the major alloying elements are enriched in the inner rust layer, which are similar to that of the base metal. In the early stage during the corrosion process, the welded joints with inhomogeneous structure show the poorer corrosion resistance than that of the base metal. However, it looks the opposite way around in the late corrosion stage, when the uniform corrosion products with even thickness of the base metal tend to detach from the substrate easier and earlier and resulting in cracks, which increase the corrosion rate comparatively with that of the welded joints.

09CuPCrNi low alloy steel is a kind of typical weathering steel developed in China which is similar to Corten A developed by USA. Nowadays, 09CuPCrNi low alloy steel is widely adopted in many fields which require welding processes. In the past years, the research of weathering steel welded joints was mainly concentrated on the strength, toughness and weldability. Less work has been done to investigate the difference of corrosion evolution and characteristics between the base metal and its welded joints. Thus, the main objective of the present work was to analyze the influence of welding on the atmospheric corrosion.

Combustion modifications to minimize NO_X emissions have magnified the importance of waterwall corrosion in coal‐fired boilers. The physics and chemistry controlling corrosion processes can be highly non‐linear and are challenging to describe in terms of their likely overall combustion behavior. This paper describes the application of a multi‐point, real time corrosion surveillance system to a large boiler firing high sulfur coal. This technology, incorporating electrochemical sensing and wireless signal transmission, enables combustion engineers and plant operating personnel to make informed decisions regarding the quantitative relationships between operating conditions, NO_X emissions, and any resultant extent/magnitude of waterwall corrosion.

This paper describes the effect of alloying elements such as Nb and Ga on the corrosion behaviour of Nd‐Fe‐B permanent magnetic alloy. The results revealed that the alloying elements are not helpful in improving the corrosion resistance of the base magnet; rather their presence makes the base alloy highly vulnerable to corrosion in acidic environments. In particular, Nb addition is more detrimental to corrosion as was evidenced by potentiodynamic, cyclic polarisation, E_corr vs time, electrochemical impedance and SEM results. The studies also showed that the degradation of the alloys with and without alloying addition takes place due to preferential dissolution of grain boundaries.

The purpose of this investigation was to develop a digital instrument for the quantitative evaluation of pitting corrosion in metals.

This investigation comprised two central parts: research, testing and monitoring of the formation of pitting by conventional methods and applying American Society for Testing and Materials (ASTM) Standards, and the development of a virtual instrument based on the LabVIEW 2010 platform.

The methodology used was suitable for the analysis of pitting on carbon steel and aluminum alloy UNS A96061, used in the aerospace industry.

This technique allows pits to be to localized, measured and quantified on metallic surfaces, for corrosion evaluation in atmospheric and industrial environments.

This combination of conventional and digital methods can assist in corrosion control of pitting in industrial equipment.

Introduction As described in the first article in this series, for the past 40 years the Corrosion Group at Teddington has been concerned with a very wide spectrum of both corrosion research and corrosion information. The work of the Group in this time has included many aspects of atmospheric, immersed, and underground corrosion, and has ranged from fundamental studies of corrosion processes, to applied researches such as the study of the pitting of tubes in locomotive and marine boilers, the corrosion caused by coolants used for internal combustion engines, and the development of inhibitors to combat both immersed and atmospheric corrosion. Through‐out this period we have maintained a complete bibliography on corrosion, together with an active Advisory Service for the diagnosis and solving of industrial and other problems.

Sour water condensates are aqueous condensates which contain different concentrations of aggressive compounds such as HCl, H2S, CO2, NH3, cyanides, etc. These condensates which can be fairly corrosive are encountered in a variety of refinery processes ranging from atmospheric distillation units to hydrodesulphurisers and sour water strippers. This paper deals with the mechanism of corrosion by these condensates and the factors influencing corrosion in several typical refinery units. In addition, methods for corrosion prevention and control are also discussed.