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Graphite fluoride fibers and their applications in the space industry
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Long, Martin Hung, Ching-Chen Dever, Therese |
| Copyright Year | 1990 |
| Description | Characterization and potential space applications of graphite fluoride fibers from commercially available graphitized carbon fibers are presented. Graphite fluoride fibers with fluorine to carbon ratios of 0.65 and 0.68 were found to have electrical resistivity values of 10(exp 4) and 10(exp 11) Ohms-cm, respectively, and thermal conductivity values of 24 and 5 W/m-K, respectively. At this fluorine content range, the fibers have tensile strength of 0.25 + or - 0.10 GPa (36 + or - 14 ksi), Young's modulus of 170 + or - 30 GPa (25 + or - 5 Msi). The coefficient of thermal expansion value of a sample with fluorine to carbon ratio of 0.61 was found to be 7 ppm/C. These properties change and approach the graphite value as the fluorine content approach 0. Electrically insulative graphite fluoride fiber is at least five times more thermally conductive than fiberglass. Therefore, it can be used as a heat sinking printed circuit board material for low temperature, long life power electronics in spacecraft. Also, partially fluorinated fiber with tailor-made physical properties to meet the requirements of certain engineering design can be produced. For example, a partially fluorinated fiber could have a predetermined CTE value in -1.5 to 7 ppm/C range and would be suitable for use in solar concentrators in solar dynamic power systems. It could also have a predetermined electrical resistivity value suitable for use as a low observable material. Experimental data indicate that slightly fluorinated graphite fibers are more durable in the atomic oxygen environment than pristine graphite. Therefore, fluorination of graphite used in the construction of spacecraft that would be exposed to the low Earth orbit atomic oxygen may protect defect sites in atomic oxygen protective coatings and therefore decrease the rate of degradation of graphite. |
| File Size | 7839795 |
| Page Count | 12 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910001749 |
| Archival Resource Key | ark:/13960/t57d7sg4v |
| Language | English |
| Publisher Date | 1990-08-01 |
| Access Restriction | Open |
| Subject Keyword | Durability Modulus of Elasticity Fluorides Spacecraft Construction Materials Tensile Strength Glass Fibers Thermal Expansion Carbon Fibers Oxygen Atoms Low Earth Orbits Electrical Resistivity Graphite Thermal Conductivity Fluorination Protective Coatings Technology Utilization Graphitization Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
