Abstract
Nitride ceramics have been investigated for different applications in the nuclear industry, such as space nuclear power, fusion reactor diagnostics and plasma heating, inert matrix fuels, and accident tolerant fuels. Although thermal conductivity remains one of the most important properties to track following irradiation, traditional techniques such as laser flash and xenon flash are limited to bulk sample characterization, which requires lengthy and cost-consuming neutron irradiation. This work used spatial domain thermoreflectance (SDTR) for the micrometer-scale measurement of thermal conductivity in 15 MeV Ni ion-irradiated silicon nitride and zirconium nitride from 1 to 50 dpa and 300 to 700 °C. The SDTR-measured unirradiated thermal conductivity was found to be consistent with the published data on bulk samples. Electrically conductive ZrN exhibits modest reduction after irradiation which is minimal at the highest irradiation temperatures. In electrically insulating Si3N4, the reduction is more significant and unlike ZrN, the reduction remains significant even at a higher irradiation temperature. The thermal resistance evolution following irradiation was compared with lattice swelling, which was determined using grazing incidence x-ray diffraction, and radiation-induced defects were observed using transmission electron microscopy. A saturation value was observed between 15 and 50 dpa for thermal conductivity degradation in both nitride ceramics and a direct correlation with high-temperature defect recombination was observed, as well as the potential presence of additional carrier scattering mechanisms.
| Original language | English |
|---|---|
| Article number | 075105 |
| Journal | Journal of Applied Physics |
| Volume | 132 |
| Issue number | 7 |
| DOIs | |
| State | Published - Aug 21 2022 |
Funding
This work was performed using funding received from the U.S. Department of Energy (DOE), Office of Nuclear Energy under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. M.K. acknowledges support from the Center for Thermal Energy Transport under Irradiation, an Energy Frontier Research Center funded by the US DOE, Office of Science, Basic Energy Sciences. J.F. acknowledges the support from the Nuclear Regulatory Commission Graduate Student Fellowship Program. A.J.T. and A.T.N. acknowledge the support of Alicia M. Raftery for the sample preparation using the spark plasma sintering system. L.W. would like to acknowledge the support from the US DOE, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under Contract No. DE-AC02-76SF00515. The XRD analysis was performed at the Joint Institute for Advanced Materials Diffraction Facility and the ion irradiations were performed at the Ion Beam Materials Laboratory. Both user centers are located at the University of Tennessee, Knoxville. Spatial domain thermoreflectance was performed at the Thermal Properties of Materials for Extreme Environments laboratory at the Ohio State University in Columbus, Ohio. The TEM analysis was performed at the Low Activation Materials Development and Analysis facility at Oak Ridge National Laboratory.
| Funders | Funder number |
|---|---|
| Center for Thermal Energy Transport | |
| U.S. Department of Energy | |
| U.S. Nuclear Regulatory Commission | |
| Office of Science | |
| Office of Nuclear Energy | DE-AC05-00OR22725 |
| Basic Energy Sciences | |
| Laboratory Directed Research and Development | DE-AC02-76SF00515 |
