It is a known fact that Pb electrode is severely corroded in the presence of Cl ion.
Now, two-component alloys such as Pb-Ag or three-component alloys consisted of Pb-Ag added with Sb, Sn, etc., showed a remarkable corrosion resistant behavior as compared with simple Pb electrode in artificial sea-water.
For the purpose of studying this phenomenon, it was examined the current-voltage curve of Pb, Pb-Ag, etc., in the solution of 0.5N-Na₂SO₄, 0.5N-NaCl and artificial sea-water.
The results obtained are as follows:
(1) In 0.5N-Na₂SO₄ solution, Pb-Ag, Pb-Ag-Sb and Pb-Ag-Sn electrode showed a similar curve as Pt electrode but oxygen evolution voltage was 1.15V referred to S. C. E. Oxygen evolution voltage of Pb was greater than Pb-Ag electrode.
(2) In 0.5N-NaCl solution, the chlorine evoluting voltage of Pb-Ag electrode was greater than Pb electrode.
Ag and Sn did not show a remarkable passive phenomenon in the current-voltage curve.
(3) In artificial sea-water, Pb electrode showed almost the same current-voltage curve as Pb-Ag electrode.
In the detailed analysis of those curves, it was confirmed that at the Pb electrode, the electric current is produced by chlorine evolution, and at the Pb-Ag electrode, it is produced by the oxygen evolution.

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Three kinds of amine-type corrosion inhibitors, N-propyl-n-dodecyl amine, N-(2-hydroxyl propyl)-n-dodecyl amine and N-(2, 3-dihydroxyl propyl)-n-dodecyl amine are studied.
Chemical structures of these amines differ only in number of hydroxyl groups, which make them active in water. Soluble inhibitors are more mobile in water, so the better inhibition are maintained with them than with insoluble ones. But, on the contrary, more soluble inhibitors are able to depart more easily from metal surfaces than insoluble ones, so with soluble inhibitors, better inhibition can be obtained only when they are used in large amounts.
In conclusion, the best inhibition, we suggest, may be obtained from making insoluble inhibitors. and solvents disperse in corrosive media, with minimum amounts of emulsifiers.

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