Zairyo-to-Kankyo
Online ISSN : 1881-9664
Print ISSN : 0917-0480
ISSN-L : 0917-0480
Volume 60 , Issue 3
Showing 1-11 articles out of 11 articles from the selected issue
Commentary
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  • Katsuhisa Sugimoto
    2011 Volume 60 Issue 3 Pages 98-108
    Published: March 15, 2011
    Released: September 01, 2011
    JOURNALS FREE ACCESS
    This paper reviews electrochemical and corrosion studies on the application of carbon steel to an overpack container, which is used for the geological disposal of radioactive wastes. Deaerated alkaline Na2SO4-NaHCO3-NaCl solutions and bentonite soaked with the solutions are used as simulated geological disposal environments. Electrochemical studies show the corrosion of the steel in an early stage is the activation control. Corrosion rates are controlled by the composition of the solutions, alloying elements, and the structure of the steel. The rates decrease with time due to the formation of FeCO3 (siderite) film on the steel. Immersion corrosion tests show general corrosion morphology. Average corrosion rates of long duration have been evaluated. Clear proofs of the initiation of localized corrosion, such as pitting, crevice corrosion, hydrogen embrittlment and stress-corrosion cracking, have not been reported.
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Rapid Communication Note
Research Paper
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  • Yukitoshi Takeshita, Seizou Sakata, Takashi Sawada, Richard A. Jackson ...
    2011 Volume 60 Issue 3 Pages 147-153
    Published: March 15, 2011
    Released: September 01, 2011
    JOURNALS FREE ACCESS
    Many telecommunication facilities are protected against long-term weather exposure by some type of weathering prevention technology. The steel poles used by radio stations are coated with polymer material to ensure both a long lifetime and reliability. Our goal is to develop a new technique for measuring the adhesive performance of a polymer film coating on galvanized steel by using a rheological approach. Conventional adhesion testing has proved difficult to reproduce, thus limiting its usefulness. In this study, we investigated the dynamic behavior of the polymer film, tried to evaluate the adhesive performance, and estimate the trend of the mechanical properties. Additionally, we have tried to correlate data obtained in a conventional way with data obtained with the rheological technique to predict the mechanical properties over the lifetime of the material. The result clearly shows the large time dependence of the mechanical properties. Continued film degradation during artificial accelerated cycle testing reveals the corresponding trend for dynamic storage and the loss modulus. We also found that it is possible to predict the potential breaking locations and the degree of strength of polymer films by comparing the results of conventional adhesive performance testing and our new rheological findings.
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