The Effect of Sulphur on Hydrogen Recombination on Iron
The hydrogen evolution reaction on metals, and particularly on iron, has been widely studied in the past. In addition to fundamental aspects (1), this reaction is most important on the applied level, since it is involved as the cathodic reaction in the corrosion of metals. The hydrogen evolution reaction must also be considered in relation with the penetration of hydrogen into metals (2). It is well known that the presence of hydrogen in metals can drastically change the mechanical properties of the material (hydrogen embrittlement). Non-metallic impurities, such as S, As, are known to favor the penetration of hydrogen in metals. The role of these impurities is still poorly understood, while a number of hypothesis have been suggested. The aim of this work was to clarify the effect of an adsorbed impurity on the hydrogen evolution reaction on various metals. The results reported here concern the effect of sulphur on the hydrogen evolution reaction on iron. Our intention was to take into account the dependence of the reaction on the surface structure, by using single crystal electrodes, and to monitor the surface concentration of sulphur at the various stages of the reaction, by means of a radiochemical technique (35S radiotracer). This last parameter was unknown in most of the previously reported studies.
KeywordsHydrogen Embrittlement Hydrogen Evolution Reaction Exchange Current Density Permeation Flux Single Crystal Electrode
Unable to display preview. Download preview PDF.
- (2).Proc. 2nd Int. Cong. Hydrogen in Metals, Paris France (1977).Google Scholar
- (3).Y. Berthier and J. Oudar — C. R. Acad. Sci. Paris 269 (1969) 1 149.Google Scholar
- (4).K. J. Vetter — Electrochemical Kinetics, Academic Press, London (1967).Google Scholar
- (5).J. O. M Bockris, A.K.N. Reddy — Modern Electrochemistry, Plenum Press, New-York (1970).Google Scholar