Nickel anodic behaviour

Myers, J. R., Crow, W. B., Beck, F. H. and Saxer, R. K., Observation on the Anodic Behaviour of Nickel and Chromium Surface Topography and Temperature Effect , Corrosion, 22, 32 (1966)... 

Fig. 3.36 Effect of nickel on the anodic behaviour of iron alloys in 1 N H2SO4 at 25°C. Curve 1 Fe curve 2 Fe-lONi Curve 4 Ni (after Beauchamp )...

Many investigators have studied the anodic behaviour of nickel. A complete discussion of the reactions occurring during anodic dissolution and passivation of the metal is outside the scope of this chapter, which is confined to a brief summary of the main features of practical significance. 

The influence of temperature on the anodic behaviour of nickel has been studied, and in acidic and neutral solutions the active-passive transition is not observed at temperatures greater than about 100°C (Fig. 4.21). 

Fig. 4.21 Effect of temperature on the anodic behaviour of nickel in 0 025 m H2SO4 -I-0-025 M K2SO4 (pH 1 -3) de-aerated with H2. The curves were determined potentiokinetically at a scan rate of 2 V/h and proceeding from negative to positive (after Cowan and Staehle )...

As with most other metals, the anodic behaviour of nickel is influenced by the composition of the solution in which measurements are made, particularly if the solution is acidic. Acidic solutions containing d ions or certain sulphur compounds in particular have a pronounced influence both in increasing the rate of anodic dissolution in the active range and in preventing passivation, and in stimulating localised corrosion . Thiourea and some of its derivatives have a complex effect, acting either as anodic stimulators or inhibitors, depending on their concentration . 

During recent years a considerable amount of information has been published on the anodic behaviour of nickel alloys. The data include studies both of binary alloy systems in which nickel forms the major alloying component and of more complex commercially produced nickel alloys. The data are sufficiently numerous to permit a rational and fairly complete interpretation of many of the corrosion-resistant properties of nickel alloys on the basis of their anodic behaviour. 

Table 4.24 Influence of alloying on anodic behaviour of nickel...

The influence of minor alloying elements and the effect of formation of other phases on the anodic behaviour of nickel alloys are thus not negligible and should not be ignored. 

Fig. 4.34 Influence of pH and Cl ions on the anodic behaviour of nickel in 804 + Cl ion solutions at 20°C (potentiokinetic polarisation at 0-05 V/min). I, 0-05 M Na2S04 + 0-02 m NaCl 2, 0 05 m HjS04 + 0 02m NaCI 3, 0.05 m H2SO4 + OO5M NaCl (after...

A. Jouarmeau, M. Keddam, and M. C. Petit, A general model of the anodic behaviour of nickel in acidic media, Electrochim. Acta 27 287 (1976). 

Zamin, M. and Ives, M. B., Effect of Chloride Ion Concentration on the Anodic Dissolution Behaviour of Nickel , Corrosion, 29, 319 (1973)... 

A metal hydride battery similar to the nickel-cadmium battery has been developed by Sharp corporation. The battery is shaped in the form of a button of 20 mm diameter and can give 1.2 V. The anode in the battery is made of La-Ni-Sn alloy hydride, and the cathode is nickel oxide. Potassium hydroxide solution in polyamide-resin is the electrolyte. The battery exhibits high energy density (i.e.) 1.5 to 2.0 times that of the Ni-Cd battery, good cycling life and superior low temperature behaviours. 

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