Self-diffusion in ice monocrystals
By: by René O. Ramseier
Contributors: Cold Regions Research and Engineering Laboratory (U.S.)
Series: Research report -- 232; Research report (Cold Regions Research and Engineering Laboratory (U.S.)) -- 232
Publisher: U.S. Army Materiel Command, Cold Regions Research & Engineering Laboratory
Published: 1967
Place of publication: Hanover, N.H
Language: eng
Number of pages: 40
Subjects: Ice crystals; Diffusion; Growth
Description: The self-diffusion of tritium, parallel and perpendicular to the optical axis of naturally occurring and artificially grown ice monocrystals, was studied between -2.5 and -35.9C. The artificial ice monocrystals were grown using a zone-melting technique. Activated samples were stored for several weeks, then sectioned by microtome and analyzed in a liquid scintillation counter to obtain the self-diffusion coefficients. The plane source solution of Fick's second law was used in treating the data. The diffusion coefficients were found to be identical for both types of ice. A slight anisotropy was found due to the geometry of the crystal; however, the activation energy was found to be 0.62 eV for all cases. Based on the experimental data, it is concluded that the diffusion takes place by a vacancy mechanism and that entire H2O molecules are diffusing, i.e., molecular diffusion occurs. Theoretical calculations using the atomic diffusion theory and Zener's theory for the initial diffusion coefficient are in excellent agreement with the experimentally determined diffusion coefficient. (Author).
Notes: "October 1967."

"DA task 1VO14501B52A02."

Includes bibliographical references (p. 40).