Methanogens capable of accepting electrons from Fe0 cause severe corrosion in anoxic conditions. In previous studies, all iron-corrosive methanogenic isolates were obtained marine environments. However, the presence methanogens with ability using as an electron donor and their contribution to freshwater systems is unknown. Therefore, understand role under conditions a environment, we investigated activities samples collected groundwater rivers. We enriched microorganisms that can grow...

Effect of a kind metal cation on corrosion mechanism A3003 aluminum alloy in tap water was investigated by electrochemical techniques and immersion tests. Corrosion rate the decreased with increase hardness cation, except for Mg2+. XPS analyses showed cations, classified as hard acid were incorporated hydroxides alloy. The results suggest that cations have inhibitory effect (e.g., Ca2+ Zn2+) or promotive Mg2+). These different effects can be explained difference molar volume between cation's...

The effect of metal cations, Na + , K Ca 2+ Mg Zn and Ni on oxide film structure morphology changes during immersion corrosion tests 3003 aluminum alloy in model tap waters was investigated by surface analysis techniques including Auger electron spectroscopy (AES), X‐ray photoelectron (XPS), scanning microscopy. hardness cations based the hard soft acids bases (HSAB) concept applied to explain passive structure. Numerous nano‐sized pits were observed after 86.4 ks water, products also...

The effect of metal cations on the galvanic corrosion behavior A3003 aluminum alloy in low concentration chloride ion containing solutions (tap waters) was examined by electrochemical noise impedance. impedance and conductance were calculated power spectrum density current potential. sum during tests suppressed addition Ca2+, Zn2+ Ni2+, while it increased with Mg2+ addition. These results may be explained passive film structure changes due to cations. obtained this study indicate that play...

本研究では，気液交番環境で低合金鋼の表面に形成する鉄さび層を断面観察および分析により解析し，気液交番環境における低合金鋼の腐食加速機構を解明することを目的とした．結果より，気液交番環境で低合金鋼には外側から赤さび層（γ-FeOOH），クラスト層（Fe3O4），内部結晶（Fe3O4），内部鉄さび層から成る多層の鉄さび層が形成することを見出した．鉄さび層は低合金鋼が水膜環境下に暴露されることで形成し，その構造に起因してカソード反応は常時水中に浸漬された場合よりも加速された状態を維持していたため，低合金鋼の腐食速度は増大したと考えられる．

Using two types of image processing techniques without machine learning, edge extraction and keypoint processing, progressively corroded regions under the rust layer from images steel surfaces was extracted. We found that there a relatively good correlation between strength obtained for HSL transformed histogram flattened surface corrosion depth after removal.

In order to clarify the effect of metal cations (Zn2+, Mg2+, Na+) in aqueous solution on hydrogen absorption into iron, amount from iron surface was measured by electrochemical tests with a laser ablation. Moreover, obtain basic mechanism adsorption cation, we obtained potential adsorbed atom and electronic state around using first principles calculations. Peak value permeation current time until reached peak decreased elongated NaCl, MgCl2, ZnCl2 solutions. Also, first-principles...

本研究では，気液交番環境における炭素鋼の腐食速度に及ぼす気中酸素濃度の影響を低酸素濃度の範囲で調査し，腐食試験前後の試験片の質量変化や炭素鋼表面に形成した鉄さび層の観察から気中酸素濃度により異なる炭素鋼の腐食速度や腐食機構を明らかにすることを目的とした．試験結果より，腐食速度は気中酸素濃度が増大するに伴って増加するが腐食速度の勾配は徐々に減少すること，最大侵食深さは気中酸素濃度が1％の場合を除いて気中酸素濃度が増加するに伴って増大するが気中酸素濃度が1％の最大侵食深さは5％の場合よりも大きいことを見出した．気中酸素濃度が1％の場合でのみ最大侵食深さが特異的に増大した理由は，炭素鋼に局部的な腐食が生じたためであることが断面観察から確認された．

The corrosion morphology and composition of products A3003 formed in model fresh water with different Zn 2+ concentrations were investigated by immersion tests combined surface observations analysis using an Auger electron spectroscope (AES). cross‐sectional AES showed that the thickness product layer on decreases increases concentration water. A point suggested containing (Zn > 0.1 mM) have a multilayered structure inner Zn‐rich would high protective properties.

本研究では，気液交番環境における炭素鋼の腐食速度に及ぼす海水成分の影響を調査し，更に人工海水濃度により異なる炭素鋼の腐食機構を明らかにすることを目的とした．その結果より，純水から200倍希釈人工海水までの薄い濃度領域では濃度の増大に伴って腐食速度は加速し，20倍希釈から無希釈人工海水までの濃い濃度領域では濃度の増大に伴って腐食速度は減少することを見出した．濃度の高い人工海水中で炭素鋼の腐食が抑制された理由は，腐食による表面近傍のpH増大に伴い人工海水中のMgやCaイオンが反応界面に析出して表面を覆うことで，酸素還元反応が抑制されたためであると考えられる．

Corrosion mechanism and morphology changes of aluminum alloy in model solution corresponding sea water containing gluconates zinc ions were investigated by immersion corrosion tests with surface analysis. Surface cross-sectional SEM results showed that suppress the gluconates. XPS analyses indicated solutions adsorb on oxide films protective adsorbed would prevent penetration chloride to alloy. The also suggest bond film enhance inhibition ability for water.

3Dプリンタを用いて作製した装置で炭素鋼の大気腐食に及ぼす液膜厚さの影響を調査した．新たに作製した装置により，液膜厚さを正確に保持することが可能となった．異なる厚さの液膜で酸素の拡散限界電流（jlim）とアノード電流（janode）を測定した．液膜が薄くなると，jlimは増加し，janodeは減少した．jlimと拡散距離の関係から酸素の拡散係数を3.20×10－5 cm2 s－1と算出した．この結果を用いて，溶存酸素の拡散に影響を与え始める臨界厚さは0.87 mmと求められた．

Corrosion of steel in fresh water is a serious problem circulative cooling systems, supply systems and storage tanks, therefore many researchers have reported the corrosion water. 1 The initial behavior has been discussed on basis oxide films, films are generally destroyed by chloride ions. 2 On other hand, Kato et al. investigated behaviour mild focusing effects metal cations, they found that some cations show inhibiting ability. 3 However, there few study which quantitative water, effect...

In this study, a corrosion inhibitor suitable for the inhibition of primary containment vessels at Fukushima Daiichi Nuclear Power Station is investigated. Considering internal environment vessels, should inhibit freshwater carbon steel under irradiation and not come effluent standards in Japan. Herein, was devised by combining Al lactate Na molybdate that met above conditions, its mechanism It found 0.75 mM 0.25 were most inhibitive to steel. As has never been reported as metallic...

薄い液膜下における鋼の腐食に及ぼす腐食抑制剤（以下「抑制剤」と略記する）の影響を調査した．抑制剤として0.5 mmol L－1モリブデン酸ナトリウムと0.5 L－1乳酸アルミニウムを10 L－1 NaCl溶液に添加して用いた．サイフォン式膜厚制御セルを用いて試料上に1.0～0.2 mmの厚さの液膜を形成し電気化学測定を実施した．動電位分極測定では，拡散限界電流（jlim）及びアノード電流（janode）を測定し，抑制剤添加による変化を調べた．抑制剤添加によるjlimの変化は見られなかったが，janodeは減少したことから用いた抑制剤はアノード反応を抑制することが示された．また，電気化学インピーダンス測定では，溶液に試料を完全に浸漬させた場合と比較して，液膜下においてインピーダンスの挙動が異なることから，液量に応じて抑制剤の保護層の形態が変化することが示唆された．

In this study, the iron rust layer formed on low alloy steel under air-solution alternating conditions was investigated by cross-sectional observation and analysis, mechanism of accelerated corrosion clarified. The observations analysis showed that multilayered composed red (γ-FeOOH), crust (Fe3O4), inner crystal steel. It can be considered cathodic reaction rate dissolved oxygen conditions. This acceleration is reason why accelerated.

気液交番環境における炭素鋼の腐食について検討してきた結果の総合論文である．