INVESTIGATION OF ELECTRON BEAM PROCESSING OF ALUMINUM OXIDE AND RELATED MATERIALS.
Abstract
This investigation deals with the application of floatzone techniques to the growth of laser ruby crystals. Two techniques, the electron beam and the hollow cathode float-zone processes, are being studied. The electron beam float-zone technique has yielded high perfection sapphire crystals free of visual scattering centers. Crystals grown by this technique show a preferred orientation of about 85 degrees as compared with flamefusion crystals which show a 60 degrees preferred orientation. Doping of the sapphire with Cr2O3 has been accomplished with the aid of oxide melting point depressants. The resulting ruby, however, still exhibits optical scattering. These centers can be attributed to starting material inhomogeneity. Efforts are presently underway to improve the starting material quality. The hollow cathode float-zone technique makes use of a highly localized hollow cathode plasma to produce a molten zone. This technique is currently being developed in an effort to carry out float-zone crystal growth at pressures higher than are permissible with the electron beam technique. The technique has been developed to the stage where floating zones have been produced and scanned. Large crystals have not yet been produced; further improvements in plasma stability must be accomplished before large crystals can be grown by this technique. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1965
- Accession Number
- AD0626754
Entities
People
- G. T. Murray
- Harvey R. Nesor
- W. Class