Atomic oxygen interaction with spacecraft materials: Relationship between orbital and ground-based testing for materials certification

Conference · Mon Dec 31 23:00:00 EST 1990

OSTI ID:5327622

Cross, J B ^[1]; Koontz, S L ^[2]; Lan, E H ^[3]

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1. Los Alamos National Lab., NM (United States)
2. National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center
3. McDonnell Douglas Space Systems Co., Huntington Beach, CA (United States)

The effects of atomic oxygen on boron nitride, silicon nitride, solar cell interconnects used on the Intelsat 6 satellite, organic polymers, and MoS{sub 2} and WS{sub 2} dry lubricant have been studied in low Earth orbit (LEO) flight experiments and in our ground-based simulation facility at Los Alamos National Laboratory. Both the in-flight and ground-based experiments employed in situ electrical resistance measurements to detect penetration of atomic oxygen through materials and ESCA analysis to measure chemical composition changes. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN overcoated on thin silver was observed. No permeation of atomic oxygen through Si{sub 3}N{sub 4} was observed. Test results on the Intelsat 6 satellite interconnects used on its photovoltaic array indicate that more than 60--80% of the original thickness of silver should remain after completion of the proposed Space Shuttle rescue/reboost mission. Gas phase reaction products produced by the interaction of high kinetic energy atomic oxygen (AO) with Kapton were found to be H{sub 2}, H{sub 2}O, CO, and CO{sub 2} with NO being a possible secondary product. Hydrogen abstraction at high AO kinetic energy is postulated to be the key reaction controlling the erosion rate of Kapton. An Arrhenius-like expression having an activation barrier of 0.4 eV can be fit to the data, which suggests that the rate limiting step in the AO/Kapton reaction mechanism can be overcome by translational energy. Oxidation of MoS{sub 2} and WS{sub 2} dry lubricants in both ground-based and orbital exposures indicated the formation of MoO{sub 3} and WO{sub 3} respectively. A protective oxide layer is formed {approx}30 monolayers thick which has a high initial friction coefficient until the layer is worn off.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOD; Department of Defense, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5327622
• Report Number(s): LA-UR-91-3052; CONF-9109285--1; ON: DE92000190
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
360604 -- Materials-- Corrosion
Erosion
& Degradation
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
42 ENGINEERING
420500* -- Engineering-- Materials Testing
BORON COMPOUNDS
BORON NITRIDES
CALIBRATION
CHEMICAL REACTIONS
COATINGS
DIRECT ENERGY CONVERTERS
ELEMENTS
EQUIPMENT
FILMS
LUBRICANTS
MASS SPECTROMETERS
MEASURING INSTRUMENTS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
OXIDATION
OXYGEN
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
POLYMERS
SATELLITES
SILICON COMPOUNDS
SILICON NITRIDES
SOLAR CELLS
SOLAR EQUIPMENT
SPACE VEHICLES
SPECTROMETERS
THIN FILMS
VEHICLES