Casting of Halide and Fluoride Alloys for Laser Windows
Abstract
During the third quarter of this program high quality castings of both CaF2 and SrF2 were fabricated regardless lof the starting material. That is, either high purity single crystal chips or pre-treated reagent grade powder can be used to yield equivalent castings. The calorimetrically measured 5.25 micrometer apparent absorption coefficient of cast CaF2 has been consistently attained near .00045/cm. For cast SrF2, the 5.25 micrometer absorption coefficient lies near .00035/cm after correcting for surface loss. Preliminary work was begun in developing procedures for casting and annealing the alkaline earth fluorides in an inert atmosphere. Mechanical measurements on cast CaF2 show average fracture strengths ranging from a minimum near 6600 psi to near 23000 psi, depending on both the quality of polished surfaces and whether or not the polished samples are annealed prior to testing. This dependence is evidence that fracture is limited by surface flaws. Preliminary results for cast SrF2 show similar results with average fracture strengths being equivalent to cast CaF2. Originator supplied keywords include: Infrared materials; Alkaline earth fluorides; Optical properties; Mechanical properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1975
- Accession Number
- ADA157752
Entities
People
- J. Pappis
- R. T. Newberg
Organizations
- RTX