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

Abstract

Modulated IR radiometry, based on intensity‐modulated laser beam heating of the coatings and IR detection of the thermal response, has been found to be the most suited to characterize coatings and thin films with respect to thickness, thermal properties, and layer structure. The potential of this non‐contact and non‐destructive measuring technique for the on‐line control of coatings and deposition processes in closed vessels is analyzed here.

The Role of Modulated IR Radiometry Measurements in the Characterization of ZrON Thin Films

“…A more detailed description of the setup used for modulated IR radiometry can be found in ref. [10] Quantitative Interpretation of Modulated IR Radiometry Applied to Coatings Details of modulated IR radiometry, the measurement technique and quantitative interpretation in the case of thin films, can be found in ref. [11,12] The data directly obtained by modulated IR radiometry are the in-phase and out-of phase thermal wave signals, filtered with the help of the Lock-in amplifier at the modulation frequency of excitation from the IR radiation emitted by the coating.…”

“…[10] Quantitative Interpretation of Modulated IR Radiometry Applied to Coatings Details of modulated IR radiometry, the measurement technique and quantitative interpretation in the case of thin films, can be found in ref. [11,12] The data directly obtained by modulated IR radiometry are the in-phase and out-of phase thermal wave signals, filtered with the help of the Lock-in amplifier at the modulation frequency of excitation from the IR radiation emitted by the coating. [13] For the quantitative interpretation, the signals measured for coating-substrate systems have to be calibrated with the help of reference data measured for a homogeneous opaque body of smooth surface.…”

“…To filter the valid information from the detector response, a two‐phase lock‐in amplifier was used. A more detailed description of the setup used for modulated IR radiometry can be found in ref 10…”

“…Details of modulated IR radiometry, the measurement technique and quantitative interpretation in the case of thin films, can be found in ref 11, 12. The data directly obtained by modulated IR radiometry are the in‐phase and out‐of phase thermal wave signals, filtered with the help of the Lock‐in amplifier at the modulation frequency of excitation from the IR radiation emitted by the coating 13.…”

The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

“…Equation (5) gives the relation between t c and the thermal diffusivity a c , responsible for the spread of radiation by the sample [38]. The coefficient of thermal reflection, R cb can be rewritten as a function of the thermal effusivity ratio (e c /e b ):…”