膜厚制御された液膜下における炭素鋼の電気化学挙動

Electrochemical behavior of carbon steels under thickness-controlled solution layer

門馬 悠一郎*; 坂入 正敏*; 上野 文義  ; 大谷 恭平   

Momma, Yuichiro*; Sakairi, Masatoshi*; Ueno, Fumiyoshi; Otani, Kyohei

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密度()とアノード電流密度()を測定した。液膜が薄くなると、は増加しは減少した。と拡散距離の関係から酸素の拡散係数を3.2010 cm s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0.87mmと求められた。

The effect of solution layer thickness on the atmospheric corrosion of carbon steel was investigated using novel devices fabricated by a 3D printer. These novel devices allowed us to control the solution layer thickness precisely. Potentiodynamic polarization measurements were performed under thickness-controlled solution layer, and oxygen diffusion limiting current density () and anodic current density () were measured. As the solution layer become thinner, increased and decreased. This result indicates that corrosion accelerates when the solution layer becomes thinner. The diffusion coefficient of oxygen was calculated as 3.2010 cm s from the relationship between and solution layer thickness, and the critical diffusion thickness was estimated to be 0.87 mm.