Determination of the Temperature Dependence of the Thermal Conductivity Coefficient of Plasma-Sprayed Coatings Based on Zirconium Dioxide in the Temperature Range up to 1100 °C

Abstract

The temperature dependence of the thermal conductivity of plasma‑sprayed ZrO₂-5 wt.% CaO, (ZrO₂-5 wt.% CaO)-10 wt.% Ni, and (ZrO₂-5 wt.% CaO)-30 wt.% Ni coatings was investigated. A combined experimental and numerical approach was employed, comprising specimen heating with a propane–oxygen torch with in situ temperature field measurements and numerical simulation using COMSOL Multiphysics®. Thermal conductivity was calculated via an iterative solution of the inverse heat conduction problem. It was found that thermal conductivity increases with increasing Ni content: for the ZrO₂/CaO ceramic coating, thermal conductivity in the temperature range 20–1100°C ranged from 0.76 to 1.22 W·m⁻¹·K⁻¹, whereas for the metal–ceramic coatings containing 10% and 30% Ni, the values were 1.11–1.87 W·m⁻¹·K⁻¹ and 1.71–4.18 W·m⁻¹·K⁻¹, respectively. These results provide valuable insights for the design and optimization of thermal barrier coatings.