. The Bell System technical journal . rrosion cells and therefore of the metal specimen as awhole should move in the anodic direction as the process of inhibitiontakes place, in the case of passivating agents (which influence anodeprocesses) the effect of increasing passivation is a trend of potentialin the cathodic or noble direction. In both cases corrosion is retardedor prevented entirely. 32 BELL SYSTEM TECHNICAL JOURNAL The manner in which the conductance of the surrounding electrolyteinfluences the rate of corrosion is illustrated in Fig. 4A in which theupper curve represents the cathodi
. The Bell System technical journal . rrosion cells and therefore of the metal specimen as awhole should move in the anodic direction as the process of inhibitiontakes place, in the case of passivating agents (which influence anodeprocesses) the effect of increasing passivation is a trend of potentialin the cathodic or noble direction. In both cases corrosion is retardedor prevented entirely. 32 BELL SYSTEM TECHNICAL JOURNAL The manner in which the conductance of the surrounding electrolyteinfluences the rate of corrosion is illustrated in Fig. 4A in which theupper curve represents the cathodic and the lower the anodic polariza-tion. Assuming equal anodic and cathodic areas the corroding currentdensity for the lower conducting solution is represented by M andthat for the higher conducting solution by N. In the actual casewhere anodes and cathodes are in close juxtaposition, the internalresistance is low and consequently the corroding current densityapproaches that represented by the intersection of the ^A C I \ I CURRENT DENSITY A B Fig. 4- -Effect of conductance and of electrode area on corrosion current ■= Lower conducting = Higher conducting solutions. L = Corrosion current density for cells of equal cathode and anode = Corrosion current density when ratio anode area to cathode is small. Thus far consideration has been confined for the sake of simplicityto corrosion cells in which the anodic and cathodic areas are in actual experience this is not the case. In corrosion charac-terized by pitting, the anodic area is generally small compared to thecathodic areas. This situation is illustrated in Fig. 4B in which itwill be seen that under these conditions a high corroding currentdensity corresponding to a rapid rate of attack may occur. Con-versely, in cases where the ratio of anode areas to cathode area islarge, the rate of attack will be small, being thus controlled by cathodicpolarization. In thi
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