Understanding the effect of porosity on thermal properties of yttria- stabilized zirconia using molecular dynamics

XZ Wang and XY Liu and QY Chen and W Huang and S Pilla and GY Liang, JOURNAL OF MOLECULAR LIQUIDS, 222, 88-93 (2016).

DOI: 10.1016/j.molliq.2016.07.018

Thermal properties of yttria stabilized zirconia (YSZ) were investigated using molecular dynamics (MD) simulation. Several YSZ samples were designed to elucidate the effect of porosity on thermal conductivity of the designed YSZ systems. Mean square displacement (MSD), vibrational density of state (VDOS) and atomic movement in designed YSZ and other samples were also investigated. Results of MD simulation indicated the key role of pores in preventing thermal transport behavior. For same volume of a single pore, samples with larger pore volume showed smaller thermal conductivity (K), while for same amount of total porosity, samples with small-sized pores displayed a smaller thermal conductivity. The latter was due to the presence of relatively larger number of smaller-sized pores as compared to larger-sized ones. Samples with smaller-sized pores in greater numbers also exhibited lower vibration frequency and lower amplitude of single atoms, suggesting smaller thermal conductivity (K) values. For constant pore volume, YSZ samples were observed to have a decrease in thermal conductivity with increasing number of pores. Among YSZ samples with same levels of porosity, those with smaller pores displayed smaller thermal conductivity. Similar levels of thermal conductivity could be acquired in samples with smaller pore amounts and/or smaller porosity as compared to those with larger pores. (C) 2016 Published by Elsevier B.V.

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