|About this Abstract
||Materials Science & Technology 2019
||Materials for Nuclear Applications
||PVD Coating of Surrogate Fuels for Deep Space Nuclear Thermal Propulsion
||Maanas Togaru, Thomas Koenig, Gregory B. Thompson
|On-Site Speaker (Planned)
||Gregory B. Thompson
Nuclear thermal propulsion (NTP) is being considered for deep space exploration. However, the use of hydrogen gas as a propellant poses a challenge to the nuclear fuel (used for heating) where upon a deleterious reaction with the fuel can occur. One mitigating strategy to protect the fuel is to provide a conformal coating to serve as a diffusion barrier. Physical vapor deposition (PVD), using magnetron sputtering, has been employed. A rotating drum shifted the ZrO2 powder under a tungsten cathode, with conformal coating thicknesses ranging tens to hundreds of nanometers depending on coating times. As the coating thickened, the film revealed a ‘powdery’ morphology, which is contributed to the impact from powder-on-powder contact during coating. Precession electron diffraction revealed nanocrystalline grains in the coating with no preferred texture. Stoney curvature measurements of W on ZrO2 indicates compressive growth stress states, which will be explained by a kinetic model.