Low thermal conductivity mechanism of co-doped ceramics for thermal barrier coatings applications

摘要

The product of Hamiltonian and entropy as a new physical quantity is introduced to quantitatively explain the phenomenon that Co-doped crystals have lower thermal conductivities than single-doped crystals, because Hamiltonian does not characterize the disorder degree of Co-doped crystals. An application of the new quantity in combination with software VASP for Co-doped SrZrO3 was given in this work. It is found that in terms of Co-doped with two species of rare earth elements, the combination of La and Eu element provides the optimal solution for most efficiently decreasing thermal conductivity of SrZrO3. In addition, all cases for the different number of substitutional elements were calculated. When the number of substitutional element species is 6, and the combination consists of La, Pr, Nd, Sm, Eu and Er, the combination can most efficiently decrease thermal conductivity of SrZrO3. Finally, the correctness of the model using the Slack's method was also certified.