Sponsor
Portland State University. Department of Environmental Sciences and Resources: Physics
First Advisor
John Dash
Term of Graduation
Fall 1997
Date of Publication
1998
Document Type
Dissertation
Degree Name
Doctor of Philosophy (Ph.D.) in Environmental Sciences and Resources: Physics
Department
Physics
Language
English
Subjects
Metals -- Surfaces, Hydrogen -- Isotopes
DOI
10.15760/etd.3864
Physical Description
1 online resource (xii, 91 pages)
Abstract
The objective of this research is to characterize surfaces of metals after interaction with hydrogen isotopes. Iron, which does not readily bond with hydrogen, and palladium, which strongly bonds with hydrogen, were studied. Observations of surfaces are used to determine the nature of their metamorphosis due to such exposures. An experimental study of pure iron foil (99.99%) exposed to a hot, dense hydrogen and argon gas mixture in a ballistic compressor yielded evidence for new structural and compositional changes of the metal due to the exposure. Atomic force microscope (AFM) studies demonstrated surfaces to be highly uneven, where height variations were often 2 micrometres for many micron-sized regions scanned. An iron foil exposed to argon gases alone revealed unique dendritic patterns but negligible height variations for micron-size scans. A cold rolled single crystal palladium cathode was electrolyzed in a solution of D₂O and 15% H₂SO₄ by volume for 12 minutes. The cathode bent toward the anode during electrolysis. Examination of both concave and convex surfaces using the scanning electron microscope (SEM), scanning tunneling microscope (STM), and AFM revealed rimmed craters with faceted crystals inside and multi-textured surfaces. Also pairs of cold rolled polycrystalline palladium cathodes underwent electrolysis for six minutes or less, in D₂O and H₂O solutions, each solution containing 15% H₂SO₄ by volume. Surface morphologies of the heavy water electrolyzed samples revealed asperities, craters, and nodules, and evidence of recrystallization and crystal planes. After 1.5 years, new AFM studies of the same Pd surfaces exposed to heavy water electrolyte exhibited loose, nanometer-sized particles. However, the surfaces of Pd cathodes exposed to light water electrolyte remained nearly identical to morphologies of foils not electrolyzed, and did not change with time. No surface asperities or loose grains were observed on the latter. Secondary ion mass spectrometry (SIMS) determined the concentrations of the stable six palladium isotopes. A six minute heavy water electrolyzed sample showed inversions of Pd¹⁰⁸ with Pd¹⁰⁶ and Pd¹¹⁰ with Pd¹⁰⁴, which deviate from their natural abundance. These results support claims made by Fleischmann and Pons that nuclear transformations occur during electrolysis of Pd cathodes in heavy water solutions.
Rights
Copyright 1998 by David Samuel Silver
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Persistent Identifier
https://archives.pdx.edu/ds/psu/42957
Recommended Citation
Silver, David Samuel, "Surface Studies of Metals After Interaction With Hydrogen Isotopes" (1998). Dissertations and Theses. Paper 6742.
https://doi.org/10.15760/etd.3864
