ETCH-TUNNELS IN LITHIUM FLUORIDE CRYSTALS AND CONCERNING 'ANOMALOUS' SOLUTION AND ETCHING PHENOMENA

Abstract

The dissolution and growth behavior of LiF crystals in aqueous solutions containing longchain fatty acids as step-poisons was investigated. Both positive-crystals (whiskers and platelets) and negative-crystals (etch- tunnels) can be grown respectively from supersaturated and undersaturated solutions of LiF containing identical concentrations of stearic acid (approximately 2 x 10 to the -6th power N.). Dissolution behavior in stagnant environments is of particular interest for etch-tunnels; some 0.5 microns in diameter and more than 100 microns in length (negative-whiskers) were observed. Two types of etch-tunnel can be distinguished; those nucleated at a surface defect - such as a cleavage step or the point of emergence of a dislocation (D- type) and those nucleated at apparently random points on the crystal surface (R-type). Metallographic observations reveal that dislocations are not essential to negativecrystal growth.

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Document Details

Document Type
Technical Report
Publication Date
Dec 27, 1961
Accession Number
AD0273647

Entities

People

  • A. R. Westwood
  • D. L. Goldheim
  • H. Opperhauser
  • H. Rubin

Organizations

  • Martin Marietta

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Aqueous Solutions
  • California
  • Corporations
  • Crystals
  • Diameters
  • Fatty Acids
  • Jet Propulsion
  • Materials
  • Military Research
  • Molecules
  • Munitions
  • New Jersey
  • New York
  • Optical Materials
  • Stearic Acid

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Materials Science and Engineering.