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

Abstract

A new expression is derived for interpreting differential scanning calorimetry curves for solidstate 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 multi-layer system geometries. This expression was used to analyze two reactive multi-layer nano-laminate systems, a Zr/CuO thermite and an Al-Ni aluminide, that include systematically varied layer thicknesses. This new analysis scales DSC peak temperatures against sample geometry, which leads to geometry-independent inherent activation energies and prefactors. For the Zr-CuO system, the DSC data scales with the square of the bi-layer thickness, while for the Ni-Al system the DSC data scales with the thickness. This suggests distinct reaction mechanims between these systems.

Al atom on MoO3(010) surface: adsorption and penetration using density functional theory

“…2,8,9 The desire for and demands of new highperformance nanothermites have thus driven the study of their basic combustion mechanisms. According to the heat rate, the combustion mechanism is divided into a diffusion oxidation mechanism [10][11][12] and a melt-dispersion mechanism. [13][14][15][16][17] The former suggests diffusion of Al and oxygen atoms toward each other through the growing oxide shell, 18 which is closely related to further micro-mechanisms, such as formation of the interfacial structure and interdiffusion of atoms at the interface.…”