Reactive self-heating model of aluminum spherical nanoparticles

TL;DR

This paper introduces a self-heating model for aluminum nanoparticle oxidation based on Cabrera-Mott theory, explaining rapid microsecond-scale reactions observed experimentally, which traditional diffusion models cannot account for.

Contribution

The paper develops a novel rapid oxidation model incorporating self-heating and nonlinear potential solving, providing insights into ultrafast aluminum nanoparticle oxidation mechanisms.

Findings

Predicts oxidation times in microseconds at 2000°C

Shows self-heating significantly accelerates oxidation rates

Aligns model predictions with experimental observations

Abstract

Aluminum-oxygen reaction is important in many highly energetic, high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a "double-layer" type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 C, our model predicts overall oxidation time scale in microseconds range, in agreement with experimental evidence.