Effects of Stabilizing Treatment of Protective Rust Layer and Alloy Design on Corrosion Behavior of Weathering Steels under High Airborne Salt Condition.

Abstract

Effects of stabilizing treatment of protective rust layer and alloy design on corrosion behavior of weathering steels were investigated by long-term exposure tests under the high airborne salt condition of 0.29 mdd. The stabilizing treatment was effective to suppress penetration of chloride ion by forming protective rust layer on the steel surface at the initial period of exposure. However, the effect wore off by long-term exposure, and protective rust layer was replaced to the normal rust layer corresponding to the alloy composition under the given environment. This results clearly show that it is important to select the appropriate weathering steel which forms protective rust layer under the environment of use, even if the stabilizing treatment of protective rust layer is applied on the steel surface.

The mechanical properties and corrosion resistance of selective laser melting 30CrMnSiA steel

“…When the salt spray time is extended to 168 h, corrosion products completely covered the surface of the sample and corrosion pits could not be seen. Thus, corrosion production could hinder further corrosion of the substrate and decrease the corrosion rates for the SLM 30CrMnSiA steel after salt spray test for 168 h (Singh and Singh, 2012;Chai et al, 2016;Komori et al, 2014).…”

Year-round Monitoring of Temperature and Humidity using a Sensor Network installed in the Hokkaido Centennial Memorial Tower

“…X:時間(年)，A,B:係数に従うとされ，時間と共に減少する 11,12) 。さびは初期にはγ-FeOOH が成長し，長期間曝露後には外層，(中層)，内層にわかれる 13,14,15,16,17,18,19) 。内層は Cr な どを含む非晶質スピネル型酸化物あるいは α オキシ水酸化鉄の安定さび層となる。この内 層はカチオン透過性を示し，外層のアニオン透過性とあわせてバイポーラ構造となること でさび全体として高いイオン透過抵抗を示し，Cl -イオンの侵入やカソード反応を抑制する ことで腐食速度を低下させる 20,21,22,23) 。 実環境で長期間使用後の橋梁などの実用材あるいは 暴露材の調査が多数行われるようになり，安定さび構造の構造やイオン移動度，添加元素 の効果，融雪剤など環境因子の影響などに関して調査されてきた 12,18,19,21,22,23,24,25,26,27)…”