Zairyo-to-Kankyo
New Arrival Alert : OFF

You can use this feature after you logged into the site.
Please click the button below.

Log in / Sign up
ONLINE ISSN: 1881-9664
PRINT ISSN: 0917-0480

Zairyo-to-Kankyo Vol. 42 (1993), No. 4

  • The Influence of Cr Concentration near the Surface on Repassivation Potential for Crevice Corrosion in SUS 304L Steel

    pp. 204-210

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    When stainless steels are oxidized in air, surface oxide scales with outer chromium enriched layer and with inner chromium depleted layer are formed due to the delay of chromium diffusion from matrix to surface, deteriorating wet corrosion resistance. In this work, the influence of chromium concentration near the surface on crevice corrosion of stainless steel was studied. SUS 304L specimens were oxidized in air-opened siliconit furnace at 1, 273K for 600-2, 400s, and then removing oxide scale by mechanical polishing to measure the chromium depth-profiles by electrochemical method and repassivation potential, ER for crevice corrosion. ER were measured in 3.5% NaCl (303K, deaerated by argon), and the shapes of crevice corrosion were observed by SEM in plane and cross-section. The concentration of chromium at the surface and the grain boundary were decreased due to the selective oxidation and the quick diffusion of chromium through grain boundary. These changes near the surface induced crevice corrosion with shallow and intergranular dissolution mode, and made ER less nobel from -0.13V to -0.23V (Ag/AgCl, sat. KCl) due to the formation of sub crevice, in which repassivation was restrained.
    x

    Readers Who Read This Article Also Read

    1. Application of Oscillatory Phenomena between Active and Passive States of Irons to Thermal Sensors Zairyo-to-Kankyo Vol.42(1993), No.4
  • Rust Staining Resistance of Stainless Steels in a Marine Environment and Its Estimation Method

    pp. 211-218

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    A new electrochemical evaluation method was presented to estimate the rating number of rust staining of stainless steels in a marine environment. In this accelerated test, rust staining resistance of stainless steels was evaluated from the time to pitting under the thin electrolyte layer that was generated by the capillary phenomenon through a cotton cloth. The incubation time to passive film breakdown under this thin electrolyte layer corresponds to initial atmospheric corrosion resistance. From the results of ten years exposure test, most of stainless steels experienced severe rust staining within the first two years exposure. All the types of stainless steel have the same tendency wherein rating number changes with the square of the inverse time. The rating number of stainless steels in the marine environment can be evaluated from this time dependence and the degree of initial rust staining. The latter can be estimated by newly developed test method.
  • Corrosion Resistance of Stainless Steels Polished by Abrasive Belt-grinding Using Various Polishing Oils

    pp. 219-224

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    Investigation has been made on the corrosion resistance of stainless steels which were polished by abrasive belt-grinding using various kinds of polishing oils. Stainless steel sheets of SUS 430, SUS 430 LX, SUS 444, SUS 304 and SUS 316 were polished using a belt grinding machine which was equipped by abrasive endless belts smeared with ten kinds of mineral oils. Corrosion resistance of the polished stainless steels was examined by salt spray test, atmospheric exposure test and pitting potential measurement. The results are summarized as follows: Sulfur or its compounds which are added to the polishing oils in order to improve the abrasive belt grinding performance have harmful effects for the corrosion resistance of the stainless steels. On the other hand, other additives, i. e., phosphorus or chlorine compounds and oleic acid are almost harmless. Surface analysis of the polished stainless steels by XPS (X-ray photoelectron spectroscopy) showed that the surface oxide layer formed by the belt grinding, using the sulfurized mineral oil, contained much sulfides which caused the deterioration of the corrosion resistance of stainless steels.
  • Analytical Study of the Formation Process of Hemimorphite-Part I

    pp. 225-233

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    In order to verify the mechanism of the formation process of hemimorphite (Zn4Si2O7(OH)2·H2O) in galvanized steel pipe for water service, the synthesis of hemimorphite was performed through the application of a co-precipitation reaction, which was named the co-precipitation method. Sodium metasilicate (Na2SiO3·9H2O) solution was mixed with Zn(OH)2 colloidal solution. The precipitate obtained from the mixture was aged in aqueous solution to crystallize it into hemimorphite. The samples which were aged for the prescribed periods were analyzed using X-ray diffraction, infrared spectroscopy and thermal differential analysis. It became clear from the analysis that at the initial stage of hemimorphite formation, dissolved silicate was adsorbed onto the colloidal particles of Zn(OH)2 and precipitated with Zn(OH)2 particles; at the next stage, the adsorbed silicate broke the structure of Zn(OH)2 to form an amorphous compound as a precursor of hemimorphite; and at the final stage, rearrangement of atoms proceeded over a long period to form the framework of the hemimorphite. Furthermore, it was suggested that the OH bond of the Zn-OH-Zn bridge in the hemimorphite crystal was hard to form compared with the other bonds in the crystal.
  • Application of Oscillatory Phenomena between Active and Passive States of Irons to Thermal Sensors

    pp. 234-235

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    x

    Readers Who Read This Article Also Read

    1. The Influence of Cr Concentration near the Surface on Repassivation Potential for Crevice Corrosion in SUS 304L Steel Zairyo-to-Kankyo Vol.42(1993), No.4
  • X-ray Analysis

    pp. 236-244

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    Recently, various X-ray diffraction methods have been established for surface analysis. For example, the parallel beam method enables us to make qualitative analysis of several nanometers depth of the surface. Brief introduction about some X-ray diffraction methods for surfacelayers will be described.
  • Definition and Behavior of Small Cracks in Corrosion Fatigue

    pp. 245-253

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up
    Small fatigue cracks may propagate at higher rates than expected values based on long crack data and linear-elastic fracture mechanics, and even at lower stress intensity factor ranges than the thresholds of long cracks. Since it was reported that crack size effects were more remarkable in corrosion fatigue (CF) than mechanical fatigue, the small-crack growth mechanism has been one of the most attractive subject for CF researchers. Small CF cracks are classified into some categories according to their size scales and growth stages as well as mechanical fatigue cracks, and further into chemically small cracks of which the range is wider than the others. A number of mechanism models of small-CF-crack growth have been proposed and are classified into several groups in this paper as follows; hydrogen embrittlement models, anodic dissolution models, film rupture/slip dissolution models, chemisorption/softening models, crack closure restraint models, and distribution/coalescence models. The researches on small CF cracks, which are still in progress, are expected to contribute to the clarification of fracture mechanism of metallic materials, the development of sophisticated methods of life prediction, and so on.

Article Access Ranking

20 Sep. (Last 30 Days)

  1. Perspective toward Long-term Global Goal for Carbon Dioxide Mitigation in Steel Industry Tetsu-to-Hagané Vol.105(2019), No.6
  2. Recent Progress of Instrumentation Technology for Process Automation in Steel Industry Tetsu-to-Hagané Vol.106(2020), No.9
  3. Melting Erosion Failure Mechanism of Tuyere in Blast Furnace ISIJ International Advance Publication
  4. Accuracy Improvement of the XRD-Rietveld Method for the Quantification of Crystalline Phases in Iron Sintered Ores through the Correction of Micro-absorption Effects ISIJ International Advance Publication
  5. Evaluation and Prediction of Blast Furnace Status Based on Big Data Platform of Ironmaking and Data Mining ISIJ International Advance Publication
  6. An Empirical Comparative Study of Renewable Biochar and Fossil Carbon as Carburizer in Steelmaking ISIJ International Advance Publication
  7. Review on the High-Temperature Thermophysical Properties of Continuous Casting Mold Fluxes for Highly Alloyed Steels Tetsu-to-Hagané Advance Publication
  8. Potential Influences of Impurities on Properties of Recycled Carbon Steel ISIJ International Advance Publication
  9. 日本鉄鋼協会第94回講演大会講演概要 Tetsu-to-Hagané Vol.63(1977), No.11
  10. Numerical Simulation on Phenomena of Fine Particles Passing through an Orifice under Gas Flow Condition ISIJ International Vol.60(2020), No.7

Search Phrase Ranking

20 Sep. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. jeong-sik kim
  4. blast furnace permeability
  5. continuous casting of copper alloys
  6. エッジドロップ
  7. 柳修介
  8. isij international
  9. tetsu
  10. tetsu-to-hagane