Thermal Gradients in Thermal Analysis Experiments

Abstract

The concept of “sample temperature” in non-isothermal thermal analysis experiments is analyzed. From the analysis of the heat balance inside the sample, it is shown that the existence of such sample temperature is restricted to experimental conditions, where the thermal gradients are negligible. Two different sources of thermal gradients are studied: the sample thermal inertia and the heat of reaction that is not quickly removed. The conditions to prevent the formation of thermal gradients as well as the condition for a thermal runaway to occur are deduced. Finally, it is shown that the aspect ratio is a crucial parameter for the formation of thermal gradients within the sample.