The Carbon Materials Technology Group is supporting U.S. space programs and has developed a carbon-carbon composite impact shell for use in the radioisotope thermoelectric generators. The material has optimized energy-absorption characteristics to withstand impact and reentry temperatures should a spacecraft accidentally return to earth.
The Group has developed carbon-carbon composite control rods developed for the Modular High Temperature Gas Cooled Reactor (MHTGCR). The effects of the reactor environment such as temperature, pressure, Helium coolant chemistry and oxidation, and neutron irradiation on the properties of the graphite will be monitored to support future design. The Group will be searching for indicators of strength and strain failures such as elastic constants, fatigue behavior, fracture mechanics data, thermal physical properties, and oxidation behavior and mechanisms. Testing for the effects of neutron irradiation is a unique capability of this group. Moreover, the development of a neutron-irradiation-tolerant carbon-carbon composite material to be used as the first wall armor of future Tokamak fusion reactors has been the subject of ongoing research for several years.
The Group has developed a unique monolithic molecular sieve (CFCMS) for use in gas separations, organic removal from water streams, and gas storage. By varying the type of fiber (from a PAN-based carbon fiber to a pitch-based carbon fiber) and the activation method, the characteristics and selectivity of the sieves can be tailored to a specific application. These molecular sieves can be used for separation of molecules such as carbon dioxide and sulfur dioxide from methane in pressure- or temperature-swing adsorption systems. The Group has also developed a unique method of quickly desorbing the gasses from the sieves, resulting in faster regeneration and more efficient separations. The sieves can be used for the removal of organic compounds from waste water streams. Also, these sieves can be used to store natural gas.
The Group's unique characterization facilities for carbon-based materials include high-temperature thermal-physical properties, thermal conductivity from 190 to 2000ºC, and thermal expansion and specific heat from room temperature to 1,400ºC. We have designed our own high-temperature heat-treatment and graphitization furnace capable of graphitizations at temperatures in excess of 3000ºC in a 5-in.-diam x 30-in.-long hot zone. A high pressure test loop developed by the group allows sample exposure to environments from room temperature to 1000ºC at pressures to 1000 psi and flow rates up to 37 SCFM. The group has built a high-temperature (650ºC) 25-ton hot-press for the fabrication of composites as large as 24-in. x 25-in. Also, complete pilot-scale slurry-molding equipment is in place for fabricating parts in size ranging from 4.5-in. diam x 10-in. thick to 21-in. diam x 10-in. thick.