A non-destructive method for determination of thermal conductivity of YSZ coatings deposited on Si substrates

Thermal diffusivity (α) of YSZ coatings was determined by the phase lag method of the photo-acoustic signal for rear and frontal illuminations using a two-beam photo-acoustic cell. XRD results show the presence of a tetragonal phase with (101) and (112) orientations, and FTIR spectra exhibit the 2Eu and F1u modes as two broad bands in the frequency at 453 cm−1, 468 cm−1, corresponding to the tetragonal phase of ZrO2. Thermal diffusivity was measured in the Si/YSZ system and also on the Si (100) substrate from which a simple two-layer system model. Via specific heat measurements at constant pressure (Cp) using the (DSC) technique, and mass density (ρ) calculations using Archimedes and Aleksandrov's methods for both in-bulk and film YSZ samples, thermal conductivity (κ) was obtained. The results were: α = (0.0021 ± 0.0002) and (0.0023 ± 0.0002) cm2 s−1, ρ = (4.7725 ± 0.005) × 103 and (5.883 ± 0.005) × 103 kg m−3, Cp = (427 ± 14) J kg−1 K−1, and κ = (0.43 ± 0.06) and (0.57 ± 0.06) W m−1 K−1 for in-bulk and film YSZ samples, respectively.

► Anon-destructive method for determination of thermal conductivity.
► Novel relationship between density, porosity and thermal diffusivity in 8YSZ coating.
► Thermal diffusivity of 8YSZ coating analyzed by the phase lag method of the photo-acoustic signal.