Hydrogen Absorption during Electrodeposition and Hydrogen Charging of Sn and Cd Coatings on Iron.
Abstract
A study was made of the extent of hydrogen absorption during electrodeposition of Sn or Cd onto an Fe Substrate, and, subsequently during electrolytic hydrogen charging of the Sn or Cd-coated Fe membranes. The effectiveness of deposits, in general, for decreasing hydrogen absorption by the substrate is discussed in terms of their barrier character and of their catalytic nature for promoting the hydrogen evolution reaction. The latter is a new method for decreasing hydrogen absorption. The reduction in hydrogen absorption was found to be in proportion to the coating thickness at approx. > 1 micrometer. Analysis of the data indicates that diffusion of hydrogen through the coating is the rate determining step of the permeation process, and that the product of the diffusivity and solubility of hydrogen is in the following order: Sn < Cd < Fe. The effective diffusivity of hydrogen at 25 C in both the Sn and Cd electrodeposits approx. < 10 to the 10th power/sq cm/s. These diffusivities could be obtained in relatively short time experiments since the coatings were quite thin. As such the bilayer membrane offers advantages over the usual single layer membrane for obtaining the diffusivity of hydrogen in metals for which the permeability is very low. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 04, 1981
- Accession Number
- ADA096309
Entities
People
- A. Allam
- B. Ateya
- C. Kato
- H. W. Pickering
- M. Zamanzadeh
Organizations
- Pennsylvania State University