Photothermal characterization of amorphous thin films

Potential of Modulated IR Radiometry for the On-Line Control of Coatings

“…Such deviations from the coating's homogeneity and the effects of transparency, e.g., IR transparency in the case of plasma‐sprayed coatings,12 often are the origin for larger errors obtained in the modulated IR radiometry of coatings 13,14. Comparing the measurement and interpretation method proposed here with former work on thermal wave interferometry of layer systems and coatings, e.g., ref 1,8,10,15,. the main advantage of the present work is that an analytical inverse solution of the two‐layer thermal wave problem is used, giving unique solutions as long as the coatings are comparatively opaque and the frequency range of the relative phase extrema is not affected by the effects of transparency 9.…”

“…Modulated IR radiometry, relying on intensity‐modulated laser beam excitation and IR detection of the thermal waves, has been found to be a very useful tool to characterize thin films and coatings with respect to thickness, thermal properties, and layer structures 1,2. Due to the non‐contact remote excitation and detection, this measuring method is the most appropriate for the on‐line control of coatings and coating deposition processes in closed vessels, e.g., in physical vapor deposition (PVD), chemical vapor deposition (CVD), and sputter deposition 3,4…”

Photothermal radiometric characterization of a thin deposit using a linear swept-frequency heat flux waveform

“…There exists different experimental approaches which are all based on the front face technique: the 3 − ω technique [1], the photothermal infrared radiometry technique [2,3] and the thermoreflectance technique are the most popular [4,5]. The front face experiment consists in heating the deposit surface and measuring the temperature rise at some or several points on the heated area.…”

Experimental Investigation on the Reliability of Thermal Wave Interferometry in the Thermophysical Characterization of Plasma Sprayed Coatings

“…A number of photothermal methods using as the heating source either a modulated laser or a pulsed thermal source have been employed to determine the thickness or the thermal properties of coatings [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The current paper focuses on the analysis of the accuracy of thermal wave interferometry (TWI) in determining the thermal characteristics of coatings.…”