Corrosion Behavior of Galvanized Steel Rebar Studied by Hyperbaric-oxygen Accelerated Corrosion Test

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04226
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: DOI Kotaro 国立研究開発法人物質・材料研究機構, 構造材料研究センター, 主任研究員 (80772889)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 腐食 / 防食 / コンクリート / 表面処理 / 亜鉛 / カルシウムハイドロキシジンケート / CHZ

Outline of Final Research Achievements

The objective of this study is to elucidate the formation, growth, and degradation behavior of calcium hydroxyzincate (CHZ), a high-corrosion-resistant film formed on zinc surfaces, and to explore efficient methods for forming CHZ on zinc surfaces to develop a new corrosion-resistant surface treatment method.
In examining the formation and growth mechanism of CHZ, it was found that initially, flake-like CHZ nuclei form as point formations on the zinc surface. Subsequently, the generation of new CHZ nuclei and the growth of these nuclei continue, leading to the development of a dense CHZ layer. Additionally, it was revealed that zinc covered with a dense CHZ layer exhibits significantly higher corrosion resistance compared to polished zinc. Furthermore, it was demonstrated that anodizing can be employed to produce colored films on zinc.

Free Research Field

腐食科学、環境材料学、電気化学

Academic Significance and Societal Importance of the Research Achievements

コンクリート中において亜鉛は表面にCHZを形成するため、亜鉛めっき鉄筋は高い耐食性を示す。本研究でCHZの形成・成長・劣化メカニズムが明らかになったため、より高耐食性を示す亜鉛めっき鉄筋の開発やコンクリート中での亜鉛めっき鉄筋の劣化挙動の理解に貢献できると考えられる。また、コンクリート中以外でもCHZを加速形成できることが分かったので、コンクリート分野以外でも亜鉛の表面処理として発展できる可能性を示すことができた。