Grain-size dependent thermal conductivity of Gd2Zr2O7 ceramics

In this work, the grain-size dependent thermal conductivity of Gd2Zr2O7 (GZO) ceramics has been studied. The investigation show that the thermal conductivity limit of the GZO ceramic can be achieved when the grain size is reduced to similar to 7.5 nm. The very low thermal conductivity can be related to the high volume fraction of grain boundary/triple junction phases (GB/TJ) in nanocrystalline GZO ceramic, which is comparable to that of the grain phase. This result demonstrates that reducing grain size is a valid strategy to decrease the thermal conductivity in polycrystalline materials. Significantly, this grain-size dependent thermal conductivity can be described by a simple composite model, which treated the nanocrystalline GZO ceramic as a two-phase mixture model consisting of grain phase and GB/TJ phase.

Automated summary

This work investigates the grain-size dependent thermal conductivity of Gd2Zr2O7 ceramics. It finds that the thermal conductivity limit can be reached when the grain size is reduced to around 7.5 nm. The low thermal conductivity can be attributed to the high volume fraction of grain boundary/triple junction phases in the nanocrystalline GZO ceramic, which is comparable to that of the grain phase. This study demonstrates that reducing grain size is an effective strategy to decrease thermal conductivity in polycrystalline materials.