Chemistry of halide window growth. Final technical report, 1 Apr 1974--30 Sep 1975
The chemistry of reactive atmosphere processing (RAP) for the growth of crystals of chlorides, bromides, and halides was studied. The purity and freedom from extrinsic absorption obtained by RAP are important in the application of halides as optical elements in high power lasers. The prototype of RAP is CCl/sub 4/ in the growth of KCl; it reacts directly with water to scavenge out all traces of this contaminant and pyrolyzes with the formation of nascent halogen to react rapidly with hydroxide ions in the melt. The approach with the bromides and fluorides has been to seek RAP agents which simulate the behavior of CCl/sub 4/ with KCl. On the basis of its hydrolysis behavior, CH/sub 2/ Br/sub 2//He was used as the RAP agent for KBr. This has consistently yielded material with a 10.6 micrometer bulk absorption coefficient of 1/.0002 cm, an order of magnitude below that of non-RAP Kbr. Further improvement is possible. In addition, it was found that the minimum-melting solid solution of NaBr and KBr prepared under RAP conditions does not retain phase homogeneity below the melting point, making it impossible to grow single crystals of this material. Work on KCl toward problems associated with the scale up of RAP to produce KCl crystals of greater than 10-cm diameter. Hydrogen fluoride, previously used alone as a RAP agent for fluoride crystal growth, is fast acting but does not achieve a low RAP index, P(H/sub 2/O)/P(HF). Supplementing it with a fluorocarbon an improved transparency with CF/sub 4/ admixtures was achieved. (GRA)
- Research Organization:
- Hughes Research Labs., Malibu, Calif. (USA)
- OSTI ID:
- 7238917
- Report Number(s):
- AD-A-021326
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420300* -- Engineering-- Lasers-- (-1989)
ALKALI METAL COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
CARBON TETRACHLORIDE
CHLORIDES
CHLORINATED ALIPHATIC HYDROCARBONS
CHLORINE COMPOUNDS
CRYSTALS
HALIDES
HALOGEN COMPOUNDS
HALOGENATED ALIPHATIC HYDROCARBONS
LASER MATERIALS
LASERS
OPENINGS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
POTASSIUM BROMIDES
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
RESEARCH PROGRAMS
WINDOWS