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和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.