Polarization resistance and weight loss of mild steel were measured in 1% sodium chloride solution containing various quantity of sodium silicate as a corrosion inhibitor. The effect of adding a certain kind of metal chloride to the above solution was also investigated.
It was found that the corrosion rate decreases as the polarization resistance increases, and their relation was obtained to be linear on log-log plot. Based upon this relationship, the corrosion rate, including its time variation, can easily be estimated by the measurement of polarization resistance. This method of evaluating the effectiveness of corrosion inhibitors has a superiority such as it can be conducted without taking the specimen out of the solution.
In the course of the present investigation, a considerable increase in the inhibiting effect of sodium silicate was noticed by the presence of either one of Zn⁺⁺, Mn⁺⁺ and Ni⁺⁺ ions. It was also found that there exists a certain weight-ratio to make the inhibiting effect maximum.

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The large majority of condenser tubes in use at the present time is manufactured of copperbase alloy, primarily because these materials exhibit excellent corrosion resistant properties under the various conditions of service to which they are exposed. The high thermal conductivity and favorable physical properties of copper alloy are also of importance in this application.
Many cases of tube corrosion are experienced when an electrochemical action, generally termed concentration cell corrosion is set up. Corrosion of this type usually results in intense local pitting of the tube surface.
Especially, deposit is a form of concentration cell action initiated by lodgement of sand, mud, cinders, stones, wood, shells, iron scale, etc., on the tube surface. Intense pitting of the tube wall may take place at or adjacent to such deposits.
When the deposits is fixed on the tube wall, however, there seems to be a little detrimental effect produced by deposits, if not the cooling water flow is high speed.
This paper report on the phenomena, which is violent attack on the occasion of happening the deposits vibrate on the tube walls. The attack of this type is named the vibration deposit attack. This paper presents the results on the vibration deposit attack test, and the effect of the polluted cooling water, usually the sea water take into service.

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A relationship between the adsorption of polar organic compounds on metal and their ability to inhibit corrosion in sea water were examined. As corrosion inhibitors of ferrous metal such compounds with straight hydrocarbon chains of 16 carbon atoms, as acid amide, acid, alcohol, and amine were tested, resulting the amide the best and the amine the second. Amide group shows increased adsorption as they have equal extent of covering effects of their alkyl groups. Our inhibitors (amine-acid complexes) show resembling behaviors with the amide to inhibit corrosion of metal.
High molecular weight S-containing organic compounds seem to be effective in inhibiting corrosion of copper in sea water.

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