Assessment of the Thermal Conductivity of Yttria-Stabilized Zirconia Coating

The approach is based on an experimental set-up in which coated surface of the specimen was exposed to high temperature environment and inner metal surface was cooled by flowing air, simulating the actual gas turbine applications. The 8% yttria-stabilized zirconia coating was made by plasma spray method on a cylindrical specimen. This arrangement could be set-up in a laboratory. By measuring the overall thermal resistances of specimens, it has been shown that the thermal conductivity of the coating segment can be determined by the differences in thermal resistances of two specimens with and without coating. The objective of the present work is to extract the thermal conductivity of the thermal barrier coating under the condition that is nearly the same as the actual application. The effective thermal conductivities of coatings found to be 0.11 to 0.16 W/mK, while those measured by laser flash method in literature varied from 1 to 1.4 W/mK.