Study to Determine the Feasibility of Utilizing Skull-Melting Techniques for the Growth of Single Crystals of Yttrium Vanadate

Abstract

The goal of this program is to explore the feasibility of utilizing RF induction heated skull-melting techniques for the growth of optical quality crystals of yttrium vanadate (YVO4). In a parallel effort, experiments were also carried out to explore the fusion and recrystallization of yttrium aluminum garnet (YAG) in a cold crucible. Yttrium vanadate melts were achieved in cold crucibles up to 157 mm in diameter operating at an RF frequency of 3 MHz. However, attempts to Czochralski crystal growth were not successful due to poor thermal geometry and dissociation of the skull-contained melt. Experiments suggest that oxygen overpressures in excess of 2 atmos. may be useful in suppressing the dissociation rate of YVO4 melts. Skull-melting of YAG was achieved using an RF frequency of 3 MHz (no melting was observed at lower frequencies). However, the melts tended to slowly de-couple and freeze spontaneously; stable melts could not be maintained for periods beyond 2-3 hours.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1986
Accession Number
ADA169249

Entities

People

  • Joseph F. Wenckus
  • Wilson P. Menashi

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Atmospheres
  • Controlled Atmospheres
  • Crucibles
  • Crystal Growth
  • Crystals
  • Czochralski Crystals
  • Diameters
  • Dissociation
  • Frequency
  • Heat Energy
  • Metals
  • Phase Diagrams
  • Radio Frequency Power
  • Single Crystals
  • Temperature Gradients
  • Transition Temperature
  • Yttrium Aluminum Garnet

Fields of Study

  • Physics

Readers

  • Materials Science and Engineering.
  • Radio communications and signal processing.