Thermal diffusivity (alpha) 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 2(Eu) and F-1u 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 (C-p) using the (DSC) technique, and mass density (rho) calculations using Archimedes and Aleksandrov's methods for both in-bulk and film YSZ samples, thermal conductivity (k) was obtained. The results were: alpha = (0.0021 +/- 0.0002) and (0.0023 +/- 0.0002) cm(2) s(-1), rho - (4.7725 +/- 0.005) x 10(3) and (5.883 +/- 0.005) x 10(3) kg m(-3), C-p = (427 + 14) J kg K-1(-1), and K = (0.43 + 0.06) and (0.57 +/- 0.06) W m K-1(-1) for in-bulk and film YSZ samples, respectively. (c) 2012 Elsevier B.V. All rights reserved.