Fourier Law Fidelity Contrasted by Infrared Imaging as Heat Flows through Metals and Polymers

Abstract

Using a home-built imaging system to map by infrared detection the surface temperature of a metallic material, we fail to confirm the generality of previously reported deviations, for translucent polymers and quartz, from Fourier’s law at the macroscale. This discrepancy is explained by the fact that unlike polymers and quartz, metals are optically opaque. Comparing the environments of air and vacuum quantitatively, we show the advantage of the latter environment. Of special interest is that thermal gradients reveal surface features otherwise concealed under uniform temperature conditions. Our findings not only confirm the classical heat conduction model for metal but also highlight the often-overlooked impact of material optical properties on thermal behavior.