Zairyo-to-Kankyo
Online ISSN : 1881-9664
Print ISSN : 0917-0480
ISSN-L : 0917-0480
Volume 68, Issue 7
Displaying 1-6 of 6 articles from this issue
Commentary
Technical Review
Conference Publication
  • Hiroki Harada, Masataka Omoda, Shinji Ootsuka, Takashi Kawano
    2019 Volume 68 Issue 7 Pages 171-177
    Published: July 10, 2019
    Released on J-STAGE: December 21, 2019
    JOURNAL FREE ACCESS

    To develop high strength steel with high resistance to hydrogen embrittlement, it is necessary to clarify the mechanism of hydrogen entry into steel. Hydrogen entry is caused by corrosion reaction under atmospheric environment. However, the relationship between hydrogen entry and corrosion behavior, and the influence of environmental factors on the hydrogen entry such as temperature, relative humidity(RH) and salt deposition are not fully understood. In this study, simultaneous monitoring of both hydrogen entry and corrosion rate was employed to investigate the influence of environmental factors on hydrogen entry and corrosion behavior. The monitoring was conducted under the atmospheric exposure test.

    As a result, hydrogen entry and corrosion rate increased with increase of amount of salt deposition. Corrosion rate increased with increase of RH, whereas hydrogen entry had a maximum at medium RH. The mechanism of promotion of the hydrogen entry at medium RH range was assumed to be related to lowering pH due to hydrolysis of Fe3+ in high [Cl] environment.

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  • Eri Matsunaga, Tadashi Minotani, Masayuki Tsuda
    2019 Volume 68 Issue 7 Pages 178-181
    Published: July 10, 2019
    Released on J-STAGE: December 21, 2019
    JOURNAL FREE ACCESS

    This paper presents a coating-type sensor for more efficient remote inspection of infrastructures that are large in scale and have complicated shapes. For crack detection, electromagnetic waves at around 0.2~2.0 GHz penetrated the coating sensor film, and we observed the reflected waves. Measurement and simulation results confirmed that the sensor detects cracks occurring in the coated films with lengths of about 15% on one side of the sensor.

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  • Toshio Horie, Gaku Kitahara
    2019 Volume 68 Issue 7 Pages 182-186
    Published: July 10, 2019
    Released on J-STAGE: December 21, 2019
    JOURNAL FREE ACCESS

    Painted steel panel uses for automotive body. Therefore, assessments of painted steel corrosion protecting life are important. Automotive body is exposed to various atmospheric environments. Atmospheric environmental factors (temperature, humidity, adhering salt type, etc.) are influenced on corrosion protecting life of the painted steel. In order to evaluate the corrosion protection performance in a short time, we study evaluation of coating film degradation using EIS (Electrochemical Impedance Spectroscopy). As a result, it was found that coating thickness, adhesion salt type and presence/absence of freezing process may contribute to degradation of corrosion protection performance.

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