Anion concentration, effect corrosion rate

Fig. 2.2 Effect of increasing anion concentration on corrosion rate of mild steel in sodium salt...

However, in the pH range 1-4, the effect of the OH ion predominates to such an extent that corrosion rates are similar in the presence of many other anions at concentrations less than 0.1 M. Since an adsorption process is involved in the mechanism, the corrosion rate in the pH range 1-4 may be represented by the Freundlich equation ... 

The effect of ultrasound on the process of tellurium anodic dissolution in alkaline solutions was studied by the method of plotting polarization and galvanostatic curves [148]. Tests were made in NaOH solutions (concentrations of 0—20 g/L), subjected to the action of ultrasound at a frequency 17.5 kHz and using Te electrodeposited under ultrasound. The anodic polarization curves plotted without ultrasound and in its presence shifted with increased NaOH concentration towards negative values as a result of the increasing rate of Te anodic dissolution. The presence of ultrasound inhibited the process of Te anodic dissolution, probably due to the desorption of OFT anions from the anode surface. This sonoelectrodeposited Te thus showed greater corrosion resistance in alkaline solution than that deposited... 

Influence of Hydrodynamic Conditions Inhibitors are often applied under conditions of liquid flow (e.g. in cooling systems or pipelines) and, consequently, the effect of the flow rate on their performance also has to be considered. First, the hydrodynamic conditions determine the transport of all dissolved species in the solution (inhibitor, H" ", OH , anions, corrosion products) and hence their concentration at the surface of the corroding metal. Since both inhibiting and corrosion-accelerating species are affected, the effect of transport on the inhibition efhciency is not easy to estimate and wiU depend strongly on the inhibition mechanism. Second, the liquid flow may exert mechanical forces on the metal surface, which may promote corrosion and counteract... 

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