New Method for Extracting Diffusion-Controlled Kinetics from Differential Scanning Calorimetry: Application to Energetic Nanostructures

A new expression is derived for interpreting differential scanning calorimetry curves for solid-state reactions with diffusion-controlled kinetics. The new form yields an analytic expression for temperature at the maximum peak height that is similar to a Kissinger analysis, but that explicitly accounts for laminar, cylindrical, and spherical multilayer system geometries. This expression was used to analyze two reactive multilayer nanolaminate systems, a Zr/CuO thermite and an Ni/Al aluminide, that include systematically varied layer thicknesses. This new analysis scales differential scanning calorimetry (DSC) peak temperatures against sample geometry, which leads to geometry-independent inherent activation energies and prefactors. For the Zr/CuO system, the DSC data scale with the square of the bilayer thickness, while, for the Ni/Al system, the DSC data scale with the thickness. This suggests distinct reaction mechanisms between these systems.