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Diffusivity of hydrogen in pure iron
Author(s) -
Bryan W. L.,
Dodge B. F.
Publication year - 1963
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690090217
Subject(s) - solubility , thermal diffusivity , hydrogen , thermodynamics , permeation , chemistry , fugacity , atmospheric temperature range , activation energy , work (physics) , diffusion , metal , analytical chemistry (journal) , chromatography , organic chemistry , biochemistry , physics , membrane
The rate of permeation of hydrogen through a highly purified iron (Ferrovac E) was measured over a pressure range of 1/30 to 300 atm. and a temperature range of 126° to 693°C. The effect of cold working of the annealed metal and of hydrogen purity were also studied. Permeability, diffusivity, and solubility were obtained from the data. Permeation rate was linear with square root of fugacity rather than pressure. No difference in ϕ or D between the annealed and cold worked tube was observed. Log D vs. 1/ T was linear over the whole range of temperature, in disagreement with recent work showing a break in the plot at about 400°C. The calculated activation energy was lower than values reported in the literature. Solubility agreed well with most previous work and did not show the break in the solubility vs. temperature curve found by some recent investigators. No ageing effect was observed nor any difference between the two grades of hydrogen. All the evidence shows that diffusion through the metal is the controlling rate process in this case.