Time-resolved imaging and spectroscopy diagnostic of aluminized RDX and pure RDX under nanosecond laser ablation

Abstract

Laser ablation is a promising method for studying the chemical reactions and energy release in explosives. In this paper, we have investigated the combustion process of pure RDX and aluminized RDX through time-resolved observation of self-emitting imaging and emission spectroscopy under laser ablation. Since the recording devices can only conduct a one-time recording, we have performed a series of experiments with different time delays between the laser ablation and recording to realize time-resolved measurement. We also designed a sample plate with square array of circular holes to load the explosive powder, and every laser ablation can be acted on a complete fresh sample to ensure consistency of the sample status. The results show that, the nanosecond laser ablation causes no persistent combustion in pure RDX, the light intensity and spectral height show a monotone decline with a short duration; The aluminized RDX under laser ablation has typical secondary reaction characteristics, and exhibits better combusting performance in duration and intensity compared to the pure one. The spectral distribution with time indicates that the emission of AlO molecule is the main reason leading to secondary reaction and persistent combustion in aluminized RDX, which directly reveals that aluminum is the key role in promoting reaction and combustion.