Online ISSN : 1881-9664
Print ISSN : 0917-0480
ISSN-L : 0917-0480
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  • ―Some Reviews Related to the Hard and Soft Acids and Bases Principle―
    Kunitsugu Aramaki
    2021 Volume 70 Issue 11 Pages 349-353
    Published: November 10, 2021
    Released: December 07, 2021

    Inhibition mechanisms of corrosion Inhibitors for metals are closely related to the hard and soft acids and bases (HSAB) principle. Markedly high inhibition efficiency of decamethyleneimine (CH210 NH was explained by the formation of a stable chemisorption bond between iron and nitrogen atoms caused by a high strain in the ring using this principle. The anodic processes of iron corrosion in the presence of inhibitive or stimulative anions were discussed on the basis of the HSAB principle.

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Conference Publication
Research Paper
  • Atsushi Omori, Saya Ajito, Hiroshi Abe, Kuniki Hata, Tomonori Sato, Yo ...
    2021 Volume 70 Issue 11 Pages 358-364
    Published: November 10, 2021
    Released: December 07, 2021

    To evaluate the effect of oxidants, which are formed by radiolysis of water under gamma ray irradiation, on the corrosion of a carbon steel in a humid environment, ozone was introduced as a model oxidant into humidity-controlled air at 50℃ in a thermo-hygrostat chamber. Corrosion monitoring of carbon steel was performed by using an Atmospheric Corrosion Monitor-type (ACM) sensor consisting of a carbon steel anode and an Ag cathode, and a Resistmetric Corrosion Monitor (RCM) sensor consisting of carbon steel sheets. The corrosion rates obtained from the outputs of the sensors were increased with the increase in relative humidity and were obviously increased with the increase in the introduced ozone concentration at each relative humidity, indicating that ozone accelerates the corrosion of the carbon steel. The effect of ozone on the corrosion acceleration is attributed to its easy reduction reaction and/or fast dissolution reaction into water compared to that of oxygen.

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  • Toshio Horie, Gaku Kitahara
    2021 Volume 70 Issue 11 Pages 365-369
    Published: November 10, 2021
    Released: December 07, 2021

    Weight reduction of automobiles is an effective way to reduce carbon dioxide emissions. To reduce the weight, the adhesion joints of light materials are expected to be widely used. However, the deterioration evaluation for the adhesion joints exposed to corrosive environments such as the salt-damaged area is carried out by destructive evaluation methods like a tensile test.

    In this study, to develop a non-destructive method to detect the deterioration of the Al/CFRP lap joints by adhesive, we investigated the change in the electrical characteristics of the joints before and after corrosion tests by electrochemical impedance spectroscopy. It was found that the impedance and the frequency dependence of the dielectric loss tangent of the joints were changed by corrosion test.

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