Photothermal radiometry for the estimation of the thickness of a protective chromium layer deposited on a steel substrate

¹ GRESPI/ECATHERM, Université de Reims Champagne Ardenne, BP 1039, 51687 Reims, France
² PROMES, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France

^a Corresponding author: jl.bodnar@univ-reims.fr

Received: 7 January 2014
Accepted: 15 May 2014

Abstract

The measurement of the thickness of a coating layer is a traditional industrial problem. Many methods of measurement are already classically used for that purpose. However, the majority of these methods require either contact with the sample to be studied, or its destruction. These constraints limit their applicability. Photothermal radiometry is already largely used in the field of thermophysical properties measurement and for the detection and characterization of defects. This method does not impose the constraints mentioned above. It could thus be a complementary technique of the classical ones. The purpose of this work is then to approach the possibilities of this photothermal method, implemented under pulse excitation and front face analysis, for the measurement of the coating thickness. Using theoretical and experimental studies, we show that the method allows a good estimation of the thickness of chromium deposits on a steel substrate, at distance, without contact and in a non-destructive way.