Resistance of Coated and Uncoated IR Windows to Seawater Corrosion. Phase IV.
Final rept. Oct 79-Jun 80,
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
Pagination or Media Count:
Germanium and chalcogenide glass specimens were submerged to a 35-foot depth in San Diego Bay for 130 days and the deterioration of their surfaces noted. The germanium specimens were coated either with multilayer antireflective infrared IR coatings, or with chalcogenide glass protective coating, while the chalcogenide glass specimens were tested bare. The submerged specimens were subjected to a forced water circulation at approximately 6-feet-per-second velocity to simulate actual operational scenarios to which a submarine-mounted IR window may be subjected. The chalcogenide AMTIR-1 glass specimens and the germanium specimens protected by the chalcogenide glass coating XF206 exhibited excellent corrosion resistance. The multilayer durable antireflection AR 40100 although not as corrosion resistant as chalcogenide glass coating, exhibited the best corrosion resistance of all AR coatings tested in this study. Other AR coatings on germanium deteriorated to different degrees. The severest deterioration took place on a germanium specimen covered with multilayer coating XF204, but even there the transmission decreased only be approximately 5 percent, in the presence of many shallow or 0.010-inch and few deep or 0.030-inch corrosion craters in the surfaces of the germanium specimens. Carbon coatings, because of their potential resistance to seawater and abrasion, have been selected as the next class of coatings for evaluation in seawater environment.
- Coatings, Colorants and Finishes
- Submarine Engineering
- Infrared Detection and Detectors