Accession Number : ADA318527

Title :   Evaluation of Hafnium-Carbide Wafers for Use in a Solar Calorimeter.

Descriptive Note : Technical paper,

Corporate Author : FRAUNHOFER-INST FUER ATMOSPHAERISCHE UMWELTFORSCHUNG GARMISCH- PARTENKIRCHEN (GERMANY F R)

Personal Author(s) : Laug, Kristi K. ; Baxter, Alan J.

PDF Url : ADA318527

Report Date : DEC 1995

Pagination or Media Count : 8

Abstract : The Solar Propulsion Group (SPG) at Phillips Laboratory will determine the efficiency of transferring heat from sunlight to a gas using carbon wafers. There will be a series of tests using a calorimeter containing porous carbon and hafnium carbide coated carbon wafers that will absorb the sunlight and transfer the heat to the gas passing through them. We had half the wafers coated with hafnium carbide to prevent carbon loss in a hydrogen rich atmosphere at high temperatures. They will degrade with each test if they are not suitably coated. We conducted a wafer bake-out test to determine if they were suitable for the calorimeter testing, and to develop a baseline for degradation checks to be conducted throughout the calorimeter test series. The preliminary results indicate that the wafers will be unaffected by the environment in the calorimeter. We developed a weight baseline to use in checking the integrity of the wafers throughout the calorimeter testing. The experiments talked about in this paper are not bi-modal in the strictest sense; a single unit supplying both power and propulsion to the spacecraft or satellite. However, in the future, we may find the solar/laser thermal propulsion system that the wafers fit into lends itself to both power and propulsion in a single unit. Therefore, the information is pertinent to this forum.

Descriptors :   *HAFNIUM COMPOUNDS, *CARBIDES, *CARBON, *CALORIMETERS, TEST AND EVALUATION, SPACECRAFT, DEGRADATION, HIGH TEMPERATURE, GASES, PROPULSION SYSTEMS, BASE LINES, WEIGHT, LOSSES, WAFERS, HEAT, POROUS MATERIALS, SUNLIGHT.

Subject Categories : Thermodynamics
      Inorganic Chemistry
      Non-electrical Energy Conversion
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE