Effect of porosity on thermal conductivity of quintuple element ceramic system materials.

With the development of aerospace technology, protective materials for hot-end components have reached higher requirements. In this paper, a (ZrxY_(1-x/4)Ta_(1-x/4)Ti_(1-x/4)Er_(1-x/4))O(x = 0.2, 0.544, 0.672, 0.796, 0.92)quintuple element ceramic system composite is studied based on the solid-phase reaction method and molecular dynamics simulation. By experimental means, ZrO₂ (99.99%), Y₂O₃ (99.99%), Ta₂O₅ (99.99%), Er₂O₃ (99.99%) and TiO₂ (99%) powder was used as raw material to prepare (ZrxY_(1-x/4)Ta_(1-x/4)Ti_(1-x/4)Er_(1-x/4))O composite by the solid-phase reaction method. The thermal conductivity of (ZrxY_(1-x/4)Ta(1- x/4)Ti_(1-x/4)Er_(1-x/4))O ceramic material was investigated computationally using the LAMMPS program. The study result shows that a consistent trend in the variation of the thermal conductivity is obtained by experiments and simulations at the interval of 200-900 °C. The thermal conductivity reaches a minimum value at x = 0.796, which proves the feasibility of molecular dynamics simulation of the thermal conductivity of multi-ceramic materials. Meanwhile, the effect of porosity on thermal conductivity was investigated, and it is found that there was a competitive relationship between the elemental ratios and the effect of porosity on thermal conductivity. When the porosity is larger than 6.67%, the effect of the porosity is the main influencing factor. when the porosity is smaller than 6.67%, the elemental ratios are the dominant factors in the thermal conductivity. [ABSTRACT FROM AUTHOR]