Effect of hard particle impacts on the atomic oxygen survivability of reflector surfaces with transparent protective overcoats
Silver mirror samples with protective coatings were subjected to a stream of 27 microns alumina particles to induce pinhole defects. The protective coating consisted of a layer of aluminum dioxide over silver followed by a layer of silicon dioxide over the alumina. Samples were prepared on both graphite-epoxy composite and fused quartz substrates. After exposure to the hard particle stream, the samples were exposed to an oxygen plasma environment in a laboratory plasma asher. The effects of both the hard particles and the oxygen plasma were documented by both reflectance measurements and scanning electron microscopy. The results indicated that oxidative damage to the silver reflecting layer continues beyond that of the erosively exposed silver. Oxidative undercutting of the silver layer and graphite-epoxy substrate continues in undamaged areas through adjacent, particle damaged defect sites. This may have implications for the use of such mirrors in a space station solar dynamic power system.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- OSTI ID:
- 6953264
- Report Number(s):
- N-87-11838; NASA-TM-88874; E-3281; NAS-1.15:88874; CONF-870133-3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
141000* -- Solar Collectors & Concentrators
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BEAMS
CHALCOGENIDES
CHEMICAL REACTIONS
COATINGS
DATA
ELECTRON MICROSCOPY
ELEMENTS
EPOXIDES
EQUIPMENT
EROSION
EXPERIMENTAL DATA
INFORMATION
METALS
MICROSCOPY
MIRRORS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLE BEAMS
PROTECTIVE COATINGS
SERVICE LIFE
SILICON COMPOUNDS
SILICON OXIDES
SILVER
SOLAR CONCENTRATORS
SOLAR EQUIPMENT
SOLAR REFLECTORS
TRANSITION ELEMENTS