Dislocation Etch Pit Formation in Lithium Fluoride

摘要: Dislocation etch pits can be formed on LiF by a dilute aqueous solution of FeF3. In this report the pit formation is described in detail, and mechanism for discussed. The nature depends character dislocation, exact composition etchant. Edge dislocations screw slightly differently; former produce deeper pits. etching inhibited some segregated impurities at dislocations, therefore aged fresh much differently. Etch probably due to preferential nucleation unit one molecule deep movement monomolecular steps across surface. relative rates these two processes determine shape rate upon dislocation energy, hence impurity content as suggested Cabrera. faster edge because their higher energy. nucleate low with impurities, lower ferric ion adsorbed surface inhibits motion steps, so that steeper, more visible are produced iron increased.