Thermal conductivity of ZrO₂-4mol%Y₂O₃ thin coatings by pulsed thermal imaging method

Thin ZrO₂-4mol% Y₂O₃ coatings were deposited onto ZrO₂ substrates by electron beam-physical vapor deposition. The coated samples revealed a feather-like columnar microstructure. The main phase of the ZrO₂-4mol% Y₂O₃ coatings was the tetragonal phase. To evaluate the influence of the coating's thickness on the thermal conductivity of thin ZrO₂-4mol% Y₂O₃ coatings, the pulsed thermal imaging method was employed to obtain the thermal conductivity of the coating layer in the two-layer (coating and substrate) samples with thickness between 56 and 337μm. The thermal conductivity of the coating layer was successfully evaluated and compared well with those obtained by the laser flash method for similar coatings. The thermal conductivity of coatings shows an increasing tendency with an increase in the coating's thickness.