Volume 33, Issue 5

Nanoporous metals have recently attracted considerable interest in a wide variety of applications, including catalysis, sensors, actuators, fuel cells, microfluidic flow controllers, and so forth. Their inherent special morphology and characteristic is expected to have superior performances, such as the open porosity, high surface area, good electron conductivity, extremely clean metal surface, and high structural stability with no agglomeration in comparison with other nanostructures. Here, we mainly review our group’s systematical studies related to nanoporous copper (NPC) from dual-phase alloy families, aiming at giving a comprehensive summary about our step-by-step progress in its fabrication, microstructure evolution, dealloying behavior, and one-step strategies to special 3-D bicontinuous porous architectures in the last 5 years. Meanwhile, some encouraging test findings on the original application of NPC in lithium ion batteries have also been covered briefly in the last part of this review, which would open a window toward their other technology applications in high-performance electrochemical devices within the green, new energy industry.

DC stray current has a great influence on the corrosion of buried pipelines. In this article, first, we deduce the equation of DC stray current interference on pipeline and determine the corresponding boundary conditions. Second, we discretize the mathematical model with boundary element method. Third, the numerical simulation software BEASY is applied to study the interference corrosion of cathodic protection system. Five types of cathodic protection (CP) interference are considered, namely, anodic, cathodic, combined, induced, and joint interference. Moreover, the effects of different parameters on the degree of the CP interference are investigated. The results show that the degree of interference will decrease with the increase of soil conductivity; smaller coating damage rate will make interference more concentrated; anode parameters have a significant impact on anodic interference but have almost no effect on cathodic interference; for combined, induced, and joint interference, the likelihood for corrosion occurrence will be high at the current outflow point on pipeline.

The role of cathodic polarisation on the corrosion of 316L stainless steel was investigated under static and dynamic conditions. The results reveal that the applied flow regime during the cathodic polarisation process has a direct effect on the corrosion behaviour of steel. The cathodic polarisation of steel under static conditions increases the oxygen reduction rate and shifts the corrosion potential towards nobler potentials. Under dynamic conditions, depending on the regime of the applied fluid flow during cathodic and anodic polarisation, the oxygen reduction rate can increase, causing the corrosion potential of the cathodically polarised steel to shift towards more positive direction. On the contrary, the oxygen reduction rate can decrease and the corrosion potential of the cathodically polarised steel shifts towards more negative potentials.

The exposure of carbon steel in marine atmospheres can lead in certain circumstances to the formation of thick rust layers (containing a number of compact laminas) that are easily detached (exfoliated) from the steel substrate, leaving it unprotected and considerably accelerating the corrosion process. This deterioration phenomenon is of particular concern in steel infrastructures located close to the sea (civil constructions, bridges, etc.), whose service lifetime can be extraordinarily limited. High times of wetness of the metallic surface and high chloride ion deposition rates play a decisive role in the formation of this type of rust. Research has been carried out for 1 year in eight pure marine atmospheres with annual average chloride deposition rates of 70–1906 mg Cl - /m 2 day. The studied carbon steels consisted of one mild steel, one conventional weathering steel (Corten A), and one high nickel (~3 wt.%) advanced weathering steel (AWS). The paper describes the environmental conditions that lead to the formation of these thick multilaminar rust layers and presents a characterisation study of this singular type of rust using a variety of analysis techniques: scanning electron microscopy/energy-dispersive X-ray spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and transmission electron microscopy/electron diffraction. The Ni-AWS shows greater resistance to the occurrence of rust exfoliation.