| Abstract Scope |
Ultra-high temperature ceramics (UHTC) have a combination of refractoriness with high thermal conductivity and good thermal shock resistance. Since thermal conductivity is an important attribute, efforts are required to develop high-fidelity models to estimate it. Porosity formed during the synthesis of UHTCs can affect their thermal conductivity. Therefore, this work aims to model the thermal conductivity of UHTCs using the CALPHAD (Calculation of Phase Diagrams) technique with the addition of porosity. Pure ZrB2 and ZrB2-based composites such as ZrB2-B4C and ZrB2-ZrC are chosen as the candidate systems. Different models to estimate effective thermal conductivity, including porosity, are the rule of mixtures, Maxwell-Eucken, and effective medium theory. These models are appended to the CALPHAD model for dense material, and the effectiveness of each model for predicting the thermal conductivity of porous UHTCs is investigated. The developed model is useful for estimating the thermal conductivity of porous materials. |