Doctoral Dissertations

Abstract

"Surface self-diffusion coefficients have been measured by a radioactive tracer method over the temperature range 614⁰ to 840⁰C on nickel (111) surfaces characterized by LEED. Previously unrecognized tracer evaporation during surface diffusion resulted in restricted spreading of the tracer at higher temperatures. A theoretical treatment of the tracer evaporation phenomenon is presented and subsequently used in the analysis of the data. The temperature dependence of the surface self-diffusion coefficient (Ds) for nickel (111) can be represented, over the experimental temperature range, by a single Arrhenius type relationship...Arguments are presented to justify an adatom surface diffusion mechanism which is characterized by trapping of the diffusing tracer atoms at ledge sites on a Terrace-Ledge-Kink (TLK) surface. The major portion of the 7.7 kcal/mol activation energy for surface self-diffusion is attributed to freeing the diffusing atom from the ledge"--Abstract, page ii.

Advisor(s)

Weart, Harry W.

Committee Member(s)

Frad, William A., 1909-1974
Leighly, Hollis, P.
Moore, Robert E., 1930-2003
Lewis, Gordon

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Sponsor(s)

Avco Corporation

Publisher

University of Missouri--Rolla

Publication Date

1968

Pagination

x, 105 pages

Note about bibliography

Includes bibliographical references (pages 77-80).

Rights

© 1968 James Ronald Wolfe, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

NickelRadioactive tracers in metallurgySurface energy

Thesis Number

T 2147

Print OCLC #

5998929

Electronic OCLC #

794121066

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Metallurgy Commons

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