Characterization of the thermal conductivity of EB-PVD ZrO2–Y2O3 coatings with a pulsed thermal imaging method

ZrO2-(2–8 mol%)Y2O3 coatings were deposited on zirconia substrates by EB-PVD. The coated layer had a columnar microstructure with intercolumnar gaps between columnar grains. Nanosized pores could be observed around feather-like grains as well as inside the columnar grains. The main phase of all coated specimens was the tetragonal phase. However, the monoclinic and cubic phase of the second phase could be detected for ZrO2-2 mol%Y2O3 coatings and ZrO2-(6–8 mol%)Y2O3 coatings, respectively. The thermal conductivity of coatings was successfully evaluated with the pulsed thermal imaging method using a combined sample of coatings and a substrate. Both the thermal conductivity and heat capacity of Y2O3-doped ZrO2 coatings tended to decrease with increasing amounts of Y2O3.