GROWTH OF SAPPHIRE DISKS FROM THE MELT BY A GRADIENT FURNACE TECHNIQUE

Abstract

Single crystal Al2O3 (sapphire) is a candidate material for various window applications. A gradient furnace technique has been developed for the growth of large sapphire disks, 7.3 cm in diameter and 1.5 cm thick, from the melt in molybdenum crucibles. The disks are free of gas bubbles and inclusions and consist of several large pie-shaped grains. Within the grains dislocation densities of 100,000/sq.cm. have been measured. The disks are essentially transparent to radiation from wavelengths of 0.25 micrometers in the ultraviolet spectrum to 4.5 micrometers in the infrared spectrum.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1970
Accession Number
AD0710235

Entities

People

  • Dennis J. Viechnicki
  • Frederick Schmid

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics
  • Space
  • Weapons Technologies

DTIC Thesaurus Topics

  • Ceramic Materials
  • Crystal Growth
  • Diameters
  • Dislocations
  • Heat Exchangers
  • Infrared Spectra
  • Massachusetts
  • Materials
  • Materials Laboratories
  • Materials Science
  • Mechanics
  • Military Research
  • New Jersey
  • Single Crystals
  • Spectra
  • Ultraviolet Spectra
  • United States

Fields of Study

  • Physics

Readers

  • Materials Science and Engineering.
  • Spectroscopy.
  • Surface Engineering/Surface Coating Technology.