Corrosion electrochemical behavior

The electrochemical behavior itself 5(6)-nitrobenzimidazole is investigated depending on media pH by classical polarography [992-994], constantly current, and variable current [995, 996], The reduction 5(6)-nitro-2-arylbenzimidazoles is carried out in DMF and H20/DMF media [997], The polarography was utilized in a study of the influence of 5(6)-nitrobenzimidazole on corrosion-electrochemical behavior of chromos steel [998],... 

Veleva, L., Chin, J., and del Amo, B., Corrosion electrochemical behavior of epoxy anticorrosive paints based on zinc molybdenum phosphate and zinc oxide, Progr. Org.Coat., 36, 211, 1999. 

I.V. Tsarenko, A.V. Makarevich and T.P. Kofman. Effect of nitro-derivatives of 1,2,4-trizole on corrosion-electrochemical behavior of low-carbon steel in aqua solutions of sodium sulfate. Electrochemistry, 1997, Vol. 33, No. 10, pp. 1177-1182. 

An XPS study of the a and P phases and of AZ91 combined with examination of their corrosion electrochemical behavior, led Song et al. (1999b) to propose the surface film model for AZ91 illustrated in Fig. 4-6. The film on the surface of the a phase was expected to consist of three layers an inner layer (IL) rich in AI2O3, a... 

Stern, M. and Bishop, C.R., Corrosion and Electrochemical Behavior, in Columbium and Tantalum, Sisco, F.T. and Epremian, E., Ed., John Wiley Sons (1963)... 

Thus, interest in the electrochemical behavior of aluminum in aqueous solutions and anodic oxides, which, until recently, was stimulated entirely by attempts to cope with corrosion, has been enhanced by the wide new areas of application. 

Even trace impurities have a profound effect on the open-circuit potential and the rate of corrosion. The electrochemical behavior is even more sensitive to alloying with small amounts of other elements [cf. Section III(5(v))]. 

This book systematically summarizes the researches on electrochemistry of sulphide flotation in our group. The various electrochemical measurements, especially electrochemical corrosive method, electrochemical equilibrium calculations, surface analysis and semiconductor energy band theory, practically, molecular orbital theory, have been used in our studies and introduced in this book. The collectorless and collector-induced flotation behavior of sulphide minerals and the mechanism in various flotation systems have been discussed. The electrochemical corrosive mechanism, mechano-electrochemical behavior and the molecular orbital approach of flotation of sulphide minerals will provide much new information to the researchers in this area. The example of electrochemical flotation separation of sulphide ores listed in this book will demonstrate the good future of flotation electrochemistry of sulphide minerals in industrial applications. 

A mechanical electrochemical equipment and corrosive couple equipment were designed in order to study the electrochemical behavior of sulphide mineral surface and galvanic interaction based on the method used by Rneer (1997) as shown in Fig. 8.1 and Fig. 8.2, respectively. 

It has not been reported whether UDI or PVI-1 Inhibit Cu corrosion in aqueous environments. In the present work the electrochemical behavior of cast films of BTA, PVI-1, and UDI on Cu has been studied in acidic solutions. The compounds were studied primarily as cast films to correlate with the above research on PVI-1 and UDI. UDI, which was found to be the most promising inhibitor was also studied as a solution species. This paper deals with the overall effects and compares the behavior of the different compounds. 

The corrosion inhibitor can also be a redox couple presenting a reversible and fast electrochemical behavior that is able to react in place of the metal. This is obtained when its redox couple potential is lower than that of the considered metal. The reversible behavior allows the continuous regeneration of the corrosion inhibitor. These reducing agents are often organic compounds soluble in aqueous solutions. A nonexhaustive list is given in Ref. [5]. 

Zhu etal. [219] have also investigated the influence of surfactants on the electrochemical behavior of zinc electrodes in alkaline solutions. In the presence of surfactants, the dendrite growth is reduced and the zinc deposit is more uniform and compact. Therefore, perfluorosurfactants can be used for decreasing the corrosion of zinc batteries. 

The corrosion behavior of semiconductors can, in principle, be described within the framework of the same concepts as for metals (see, for example, Wagner and Traud, 1938), but with due account for specific features in the electrochemical behavior of a solid caused by its semiconducting nature (Gerischer, 1970). One of the main features is photosensitivity related to a change in the free-carrier concentration under illumination. Photosensitivity underlies the phenomenon of photocorrosion. 

Figure 27 Schematic (a) Evans diagram and (b) corrosion potential vs. time behavior for localized corrosion stabilization. Line a on the Evans diagram represents the electrochemical behavior of the material before localized corrosion initiates, while line b represents the electrochemical behavior of the material in the localized corrosion site. Due to the low Tafel slope of the active site, the corrosion potential of the passive surface/local-ized corrosion site falls. If repassivation occurs, the anodic behavior reverts back to line a, and the corrosion potential increases again (line c). If repassivation does not occur, the corrosion potential will remain low (line d).

The results allowed a conclusion on the possibility of separate determination of metals and nitrotriazoles from the solution [987], The influence of nitrated 1,2,4-triazoles on corrosion and electrochemical behavior of low-carbon steels in aqueous solution of sodium sulfate has been investigated [988], The strong passivating action of nitrotriazoles on steel is caused by the formation of stable chemosorbed metal-azole films. 

The main aim of SAIE is the complete elimination of heavy metals from the coating systems an approach that primarily relies on tenacious water-insensitive adhesion and good barrier characteristics of a primer has been taken. It should be pointed out that this approach is theoretically incompatible with the approach that utilizes the primers with corrosion inhibitors, e.g., chromated primers. This is because a primer with super barrier characteristics would not allow the migration of inhibitors and would not provide enough water for their electrochemical reaction to form corrosion protection products, as described in Chapter 28. In order to further elucidate the SAIE concept, both chromated and nonchromated spray primers were employed to generate two types of plasma coating-modified systems, and their corrosion protection behaviors were investigated in this study. 

CMP is analogous to the phenomena of erosion corrosion. Normally, during corrosion of a metal, a scale forms which slows further corrosion of the metal by acting as a barrier between the metal and the corrosive medium (Section 4.3). In erosion corrosion, low corrosion rates are accelerated by the removal of this scale via an erosion or wear process. The scale, wear process, and corrosive medium in erosion corrosion are analogous to the surface layer, mechanical abrasion, and slurry chemicals of the CMP process. Thus, in principle, the same electrochemical theories that are used to understand corrosion may be applied to CMP. In this section, we discuss the electrochemical theories that are important in metal CMP. In many instances we shall refer to the electrochemical behavior of copper for illustration. However, these electrochemical principles are applicable to the CMP of all metals. 

The electrochemical behavior of copper and tantalum in different solutions was investigated using DC polarization experiments. From the polarization data, the corrosion current density and hence the corrosion rate of copper were calculated using the Stem-Geary Equation ... 

Understanding electrochemical behavior and the possible reactions can help in predicting the possibility and extent of corrosion. A reaction will only occur if there is a negative free energy change (AG). For electrochemical reactions, the free energy change is calculated from ... 

One of the most important chemical applications of ion beams is their use in corrosion science (see below). In investigations in this field one usually wants to know either the composition and thickness of oxide films or the electrochemical behavior of corroding samples (aqueous corrosion). 

Most of the data available in the literature are for subcritical conditions. Corrosion studies of iron alloys in supercritical water have not been reported. For supercritical fluid extraction and corrosion studies, a supercritical fluid reactor system for temperatures up to 530 C and pressures up to 300 atm was constructed. This system was used to determine the electrochemical behavior of type 304 stainless steel (304 S.S.), 316 S.S., 1080 carbon steel (1080 C.S.), and pure iron in supercritical water. 

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