Surface Topography of Etched Ice Crystals Observed by a Scanning Electron Microscope

Abstract

ABSTRACT. Surface topograph y of etched ice crysta ls was examin ed by a sca nning electron m icroscope in combination with a Formvar replica method . The d eep focus of the scanning electron microscope a ll owed observation of the sharply three-dimensional topography of ice surfaces. Various useful inform ation was obtain ed from microphotographs o f e tched basal and prisma tic planes, fractured surfaces, a nd grain boundaries form ed between microcrystals of ice. R EsuM E. T opographie sllperficielle de cristaux de glace sublimes par un microscope electroniqlle cl champ balayant .La topogra ph ie superfi ciell e de cristaux d e glace soumis a la sublim ation a ete exa minee dans le champ

Examination of Dislocations in Ice

“…Etch pitting has been extensively used to examine nonbasal dislocations in ice. [18][19][20][21] However, basal dislocations, which play the dominant role in viscoelastic flow of ice, are difficult to observe. Etch tracks or grooves corresponding to moving dislocations can be observed, allowing estimates of dislocation velocities, but again these are produced by gliding nonbasal dislocations.…”

“…Either the etch-pit itself or the replica can then be examined using either an optical microscope or a scanning electron microscope. There have been a number of studies using this technique, − which have revealed valuable information about dislocations in ice, such as their density at zero or very low strains and the fact that dislocations play a role in the plastic flow of ice. Etch pitting has been extensively used to examine nonbasal dislocations in ice. − However, basal dislocations, which play the dominant role in viscoelastic flow of ice, are difficult to observe.…”

Mechanism of anisotropic surface self-diffusivity at the prismatic ice–vapor interface

“…Two-fold roughening symmetry in prismatic facets has also been documented in laboratorygrown ice using scanning electron microscopy. 11,[13][14][15][16] These considerations lead us to seek a theoretical model capable of generating mesoscopic roughening that is affected by microscopic structure, and to identify conditions under which it may be applicable. Such a model has emerged in the context of metal epitaxy; 18 we will refer to it here as the epitaxial island model.…”

Observation of Dislocations in Ice

“…Etch pitting has been extensively used to examine nonbasal dislocations in ice. − However, the basal dislocations, which have the dominant role in viscoelastic flow, are difficult to observe. Etch tracks or grooves corresponding to moving dislocations can be observed, allowing estimates of dislocation velocities, but again these are produced by gliding nonbasal dislocations …”