Measurement of thermal inertia by the reflective-cavity method

Abstract

The measurement of thermal parameters is a useful tool for the evaluation of compositional or structural properties of materials of industrial interest. The increasing use of noncontact photothermal techniques to generate and sense thermal fields in materials makes thermal characterization an attractive approach for in-plant quality monitoring and process control. In an effort to increase the reliability of such measurements in conditions of unknown surface emissivity, an integrating-cavity technique is described for a quantitative evaluation of the thermal inertia of the inspected material. An analysis of the performance of such a technique as a function of the cavity geometry and internal reflectivity is presented. Examples of applications to the characterization of manufactured ceramic materials with different porosity contents are described.