Resistance of Coated and Uncoated IR Windows to Seawater Corrosion. Phase 2.
Abstract
Germanium and chalcogenide glass specimens were submerged to a depth of 35 ft. in the San Diego Bay for 120 days and the deterioration of their surfaces noted. The germanium specimens were protected with single-layer and multilayer AR coatings, and the chalcogenide specimen was bare. To simulate a submarine operational scenario, the specimens were periodically brought above the water surface, dried off, and exposed to sunshine. Germanium protected by single-layer AR coatings corroded as a result of pinholes in the single-layer coatings; however, the average transmittance of the better single-layer AR coating tested decreased less than 5 percent from pre-submersion values. Multilayer AR coatings on germanium proved better, exhibiting no pinholes and at worst only erosion of the topmost coating layers. The best of the multilayer coatings tested (Exotic Materials 40100) showed virtually no effects of corrosion and no substantial transmittance decrease in the 8- to 13-micron range. The Amorphous Materials, Inc. (AMTIR) chalcogenide glass also showed excellent results, exhibiting no significant corrosion or drop in transmittance. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1980
- Accession Number
- ADA092649
Entities
People
- J. D. Stachiw
- S. L. Bertic