Effects of sintering time and pressure on the thermal conductivity and microstructural evolution of yttrium hydride by spark plasma sintering

Moderator materials are capable of reducing neutron velocities to thermal energy levels within nuclear reactors. Yttrium hydride is recognized as an exceptionally promising moderator material due to its superior thermal stability and high hydrogen content. In this study, yttrium hydride monoliths were prepared using spark plasma sintering (SPS) technique across a range of sintering times and pressures. The impact of varying sintering parameters on the density, hydrogen content, microstructure, and thermal conductivity of the resulting yttrium hydride monoliths was systematically investigated. The findings revealed that different sintering conditions significantly influence the density, precipitated phase, grain size, and thermal conductivity of the sintered samples. Moreover, a substantial correlation between thermal conductivity and density was observed. This research provides valuable insights into the fabrication of yttrium hydride monoliths with high thermal conductivity using SPS technology.