In this study, economic and advanced coating with self-healing property for corrosion protection of Al alloy were developed. This coating can be formed on Al alloy by following procedure. The porous type of anodic oxide film was formed on Al alloy surface and pores of porous film were filled with a healing agent of coating. And then, the polyurethane coating was formed on this surface. From results of this study, it is clear that the scar formed on the specimen surface covered with this self-healing coating, by damaging mechanically, was covered by self-healing structure. This structure may form by the reaction between healing agent and vapor in air. Corrosion protection of the specimen covered with this coating, can also be kept high by the self-healing property of this coating, if this coating was damaged.

In order to evaluate the corrosion of stainless steels used in spent nuclear fuel reprocessing facilities, the immersion corrosion tests and polarization measurements were performed using R-SUS304ULC stainless steel in nitric acid solution containing a kind of radionuclides, ²³⁷Np. At temperatures above 328 K, the corrosion potential was higher than that in nitric acid solution and was near the transpassive region. From the comparison between the corrosion amount calculated by the immersion corrosion tests and the polarization resistance, the values of k＝0.018-0.025 V were obtained as a conversion factor, and the possibility of calculating the corrosion amount from the electrochemical measurement was examined.

An ultrathin （nm in thickness）, two-dimensional polymer protective film was prepared on a passivated Fe surface. A self-assembled mono-molecular layer of 15-hydroxyhexadecanoate ion HO（CH₂）₁₅CO₂^－ was chemisorbed by the stable hard acid and hard base interaction on the Fe surface passivated by anodic polarization in a borate buffer at pH 8.49. The monolayer was modified with 1, 2-bis（triethoxysilyl）ethane （C₂H₅O）₃Si（CH₂）₂Si（OC₂H₅）₃ and hydrolyzed with water. The modified monolayer was then reacted with octadecyltriethoxysilane C₁₈H₃₇Si（OC₂H₅）₃ to form the two-dimensional polymer. Passive film breakdown in the borate buffer with 0.1 M of Cl^－ was markedly protected by coverage with the two-dimensional polymer coating.

To understand details of the corrosion protection mechanism of steel in a commercially available aqueous solution of antifreeze agent containing a corrosion inhibitor, immersion tests were carried out for 168 hours in aqueous solutions prepared by adding sodium pyrophosphate, sodium gluconate or sodium citrate to rock salt. In the weight change of the steel specimens after the immersion test, the weight loss of the steel was smaller in all the aqueous solutions than in the rock salt only aqueous solution. From the SEM observations of the steel surface after immersion of the solution containing sodium pyrophosphate, a several micron thick film was formed in the inhibited corrosion part, and O, Fe, P and small amounts of Mg and Ca were detected by the EDS analysis. In the FT-IR measurements of the steel surface, an absorption peak corresponding to the PO₄^3－ structure was measured. The structure of this was different from the surface film formed by the NaCl aqueous solution containing inhibitor in previous reports.