Die Wasserstoffaufnahme von Eisen bei der Korrosion in neutralen bis schwach sauren Elektrolyten

Bei der atmospharischen Korrosion und der Korrosion in wasrigen Elektrolyten kann Stahl Wasserstoff aufnehmen. Mittels einer Permeations-Methode wird die im Eisen bei der Korrosion in verdunnten Losungen von Schwefelsaure, Salzsaure und Eisensalzen auftretende Wasserstoff-Aktivitat im pH-Bereich von 1 bis 6 untersucht. Bei pH-Werten unter 5 in sauerstoffarmen und unter 4 in luftgesattigten Losungen erreicht die Wasserstoffaktivitat Werte uber 0,1 (bezogen auf aH = 1 fur PH2 = 1 bar) und kann damit langsames Riswachstum in wasserstoffempfindlichen Stahlen auslosen. Anionen und Na+-Ionen beeinflussen diese Ergebnisse nur wenig; der Einflus von Fe3+-Ionen und des Sauerstoffgehalts der Losung wird erortert. Hydrogen uptake by iron during corrosion in neutral to weakly acid electrolytes During atmospheric corrosion and corrosion by aqueous solutions, hydrogen can enter into steel. The hydrogen activity built up in iron during corrosion by dilute aqueous solutions of hydrochloric acid, sulfuric acid and iron salts has been measured as a function of pH using a permeation technique. Below pH = 5 in oxygen free solutions and pH = 4 in air saturated solutions the hydrogen activity reaches values of more than 0.1 sufficient to cause delayed cracking of steels susceptible to hydrogen embrittlement. The anions and Na+-ions have no markable influence. The influence of Fe3+ and O2 is discussed.

[1]  R. A. Oriani,et al.  Equilibrium aspects of hydrogen-induced cracking of steels , 1974 .

[2]  M. Pourbaix.  Atlas of Electrochemical Equilibria in Aqueous Solutions , 1974 .

[3]  Koji Hashimoto,et al.  The Mechanism of Atmospheric Rusting and the Protective Amorphous Rust on Low Alloy Steel(Chemistry) , 1974 .

[4]  T. Misawa,et al.  The thermodynamic consideration for Fe-H2O system at 25°C‡ , 1973 .

[5]  Nils-Gösta Vannerberg,et al.  A microscopic study of steel surfaces exposed to a humid SO2-containing atmosphere , 1972 .

[6]  U. R. Evans.  Mechanism of Rusting Under Different Conditions , 1972 .

[7]  G. Vibrans,et al.  Diffusion von Wasserstoff in stahl mit inneren Hohlräumen , 1972 .

[8]  Nils-Gösta Vannerberg,et al.  The influence of the relative humidity and corrosion products on the adsorption of sulfur dioxide on metal surfaces , 1972 .

[9]  B. Brown,et al.  Electrochemical Conditions at the Tip of an Advancing Stress Corrosion Crack in AISI 4340 Steel , 1970 .

[10]  M. Pourbaix,et al.  Significance of Protection Potential in Pitting and Intergranular Corrosion , 1970 .

[11]  U. R. Evans.  Mechanism of rusting , 1969 .

[12]  U. R. Evans,et al.  Electrochemical Mechanism of Atmospheric Rusting , 1965, Nature.

[13]  W. H. J. Vernon,et al.  A laboratory study of the atmospheric corrosion of metals. Part II.—Iron: the primary oxide film. Part III.—The secondary product or rust (influence of sulphur dioxide, carbon dioxide, and suspended particles on the rusting of iron) , 1935 .