Thermal properties of polycrystalline NdN bulk samples with various porosities

Neodymium mononitride (NdN) pellets with various porosities were prepared by a spark plasma sintering (SPS). The thermal expansion, specific heat capacity and thermal conductivity were measured and compared with those of uranium mononitride (UN), because NdN exists in the irradiated nitride fuels. The thermal expansion and specific heat capacity of NdN were very similar to those of UN. The thermal conductivity of the porosity-free NdN was estimated from the porosity dependence of the thermal conductivity. Unlike the case of the thermal conductivity of UN, that of NdN decreased with increasing temperature.