Effects of alloying and admixed elements on the corrosion and hydrogen uptake of iron
The effects of the transition metals Mo, V, Nb, Ti, Zr and their carbides in binary and ternary iron based alloys and those of Al on corrosion and Hydrogen uptake of iron in 1M H(2)SO(4) were investigated by electrochemical permeation and surface analytical methods. The corrosion current density and the Hydrogen activity at the corroding iron surface are decreased by Mo, Zr and their carbides, and are almost unaffected or slightly increased by Al, V, Nb, and Ti. The Hydrogen permeation coefficient, diffusion coefficient (after saturation of the deep traps) and solubility in iron were determined. The results are analysed in terms of the trapping theory. The average binding energy of shallow traps for hydrogen increases with the atomic radius of the substituted elements. The effective diffusion coefficient is decreased and the hydrogen solubility is increased. The total hydrogen content of the iron alloys investigated depends mainly on the density and binding energy of the deep traps and is practically independent of the external hydrogen activity. The trapping effect of the binary iron alloys increases in accordance with the interactions between Hydrogen and atoms of the transition metals in sequence Mo, V, Nb, Ti and Zr.
Bibliographic Reference: EUR 11678 DE (1988) 59 pp.
Record Number: 198910292 / Last updated on: 1994-12-01
Original language: de
Available languages: de