Evaporation of Metal Crystals.pdf (74.79 MB)
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Evaporation of Metal Crystals

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thesis
posted on 01.05.1958, 00:00 authored by John P. Hirth

A mechanism for vaporization of solid metals involving monatomic ledges on metal crystal surfaces is deduced, and an equation is derived for evaporation rate in terns of the dynamics of these ledges. It is shown that crystal edges are a ready source for monatomic ledges. The limiting expression for the vaporization coefficient of large, perfect crystals is given as a function of pressure and temperature by α = 2/3 (p/pe ) ≠ 1/3, where pe is the equilibrium vapor pressure. The effect of screw dislocation-surface intersections on the limiting expression is developed. An equation is derived giving the perturbation due to such intersections. It is found that experimental results for silver crystals confirm various predictions of the theory. Applications of the results are considered.

History

Date

01/05/1958

Degree Type

Dissertation

Department

Materials Science and Engineering

Degree Name

Doctor of Philosophy (PhD)

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