CHEMICAL VAPOR DEPOSITED MATERIALS FOR ELECTRON TUBES.
Abstract
The program was established to investigate chemical vapor deposition as a method of producing materials or coatings for use in vacuum electron devices and microwave tubes. Isotropic CVD-BN has been deposited on W-RE wire for use as an encapsulated heater. The wire was brittle after deposition, but the coating was intact and exhibited good heat transfer capability. Multilayered structures of ZrB2 and isotropic CVD Bn have been deposited in a solenoid-controlled vapor deposition setup. The correct process conditions have been determined to achieve good layer adherence and uniformly thick layers of the proper thickness in 1in. pipe mandrels. The investigation of sealing methods for joining CVD BN to glasses and metals has been continued. The active metal process is promising for isotropic BN-to-metal seals, as is a metallizing mixture of 70% Mo, 21% Ni, and 9% Ti fired in vacuum. Seals to glass have been obtained with a silicon resin and with solder glass. Recommendations are made for procedures for cleaning and machining CVD BN. The optical transmission of several samples of isotropic CVD BN has been measured as a function of wavelength between 0.4 and 15 microns. In all samples strong absorptions are obtained between 7 to 8 microns and 12 to 13 microns. The largest differences from sample to sample are seen at 0.9 microns, and the strongest absorption at this wavelength is seen in a sample identified by X-ray diffraction as mostly rhombohedral BN. Optical absorption at 0.9 microns, coupled with physical density, seems to be a good measure of the quality of isotropic CVD BN for most electron device applications. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1967
- Accession Number
- AD0651021
Entities
People
- H. Schilling
- J. Pappis
- L. Hagen
- S. R. Steele
Organizations
- RTX