Studies on the corrosion behavior of austenitic stainless steel (Type 304) were conducted in flowing water at the temperature of 320°C and at the flow rate up to 12m/sec.
The film of corrosion product formed on the surface of steel in flowing high temperature water was composed of magnetite in contrast with the coexistence of magnetite and hematite in the case of static test.
The effects of purity, amount of dissolved oxygen and flow rate of water on the corrosion rate of stainless steel were rather complicated and related to each other.
It was revealed, however, from the results of tests that the corrosion was severest when the test water had high conductivity (>5-10^-4mho/cm) and the amount of dissolved oxygen was low (<0.3ppm). In the test water of higher oxygen content (about 2-3ppm) the corrosion was milder. The corrosion rate was reduced to the lowest value by maintaining the purity of water at higher level.
The effect of flow rate of water on the corrosion rate was noticed only in the case of tests in low purity water.
The corrosion processes in the test conditions were discussed.

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Lead alloy electrode which contains noble metals such as silver is used as the anode for cathodic protection in sea water, but the mechanism of formation of the anti-corrosive film is not known as yet.
In the previous reports, the author studied stationary polarization curves of lead, silver, etc. with a potentiostat in order to investigate the film formed on the anode in relatively short time. However, for fast electrode reaction in which several kinds of surface films are formed at high velocity, detailed study on the film formation can not be made by the stationary polarization measurement method heretofore in use. Therefore, the potential sweep method was adopted to observe the anodic polarization curves of Pb, Sb and Sn in sodium sulfate and sodium chloride solutions, and the mechanism of formation of the anti-corrosive film on the surface of these metals was investigated.
The results obtained are as follows:
(1) The anti-corrosive films formed in sodium sulfate solution are α-PbO₂ and β-PbO₂ in case of lead, Sb₂O₃, Sb₂O₄ and Sb₂O₅ in case of antimony, and SnO₂ in case of tin.
(2) The anti-corrosive films formed in sodium chloride solution are lead chloride in case of lead, antimony oxide in case of antimony, and tin chloride in case of tin.
(3) Chloride film is reduced at less noble potential than the spontaneous potential.
(4) Reduction of chloride film is more difficult than that of oxide film.

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The electrochemical behavior of low-alloy steels rusted in the atmosphere have been examined using potentiostatic technique and by coulometry. Polarization diagrams obtained in 0.1M Na₂SO₄ are characterized by pronounced cathodic currents much greater than the limiting current of oxygen depolarization, which is attributed to the reduction of overlying ferric rust. The high rate of Fe²⁺ dissolution observed when rusted steels are immersed in the solution is consistent with the polarization behavior.
Assuming that the rate of anodic dissolution or the corrosion rate of rusted steel in deaerated neutral solution is equivalent to the reduction rate of ferric rust, the corrosion rate is determined as a function of immersion time, based on the coulometric measurement of un-reduced amount of ferric oxide on specimens which have been immersed previously in the solution for various time. The corrosion rate is high immediately after immersion and decreased rapidly with time, becoming almost constant in several hours.
The rate of corrosion at a given time of immersion combined with the corresponding corrosion potential gives a plot which precisely followed the analysed or true polarization curve of the similar specimen. This demonstrated the validity of the suggested corrosion mechanism of rusted steel associated with the reduction of rust.
In the course of corrosion process ferrous ion comes out into the solution, the origin of which is traced to the dissolution of the base metal under the rust layer. The rust reduced to lower oxide, on the other hand, does not dissolve in any significant amount.

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It has been ascertained that a low alloy steel containing such elements as copper, chromium and phosphorous is more resistant to the atmospheric corrosion than ordinary steels and that the resistivity is caused by the rust layer developed after many months of rusting.
The object of this study is to reveal the role of alloying elements in the formation of such a protective layer.
This paper describes the effect of Cu(II) on the growth of Fe(III)-Fe(II) hydrated oxide aggregate formed by a new method of interfacial precipitation.
When 0.75M metallic salt solution is gently added on 3M NaOH solution in a test tube, a thin membrane is formed immediately at the interface, and after several hours it grows to a crust of hydrated oxide aggregate. This crust resembles to the natural rust in its appearence and texture and is called an artificial rust.
When mixtures of FeCl₃, FeCl₂ and CuCl₂ solutions were used, rates of formation of the artifical rusts were determined from NaOH consumption. Chemical and X-ray analysis of the artificial rusts was also performed.
It was found that the addition of at most 1mol% of CuCl₂ changes the formation process remarkably. The reactions observed during aging of the artificial rusts made from FeCl₃-FeCl₂ solutions, i.e. breakdown of the crust and growth of the spinell-type oxide crystals, are inhibited by the addition of CuCl₂.

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