# The role of ultrasound in the nucleation kinetics and Modification of product properties of 3-Nitro-1,2,4-triazol-5-one

## TL;DR

Ultrasound improves the crystal properties of NTO, making it more uniform and less sensitive to impact.

## Contribution

This study demonstrates how ultrasound affects NTO crystallization and enhances its performance.

## Key findings

- Ultrasound reduces the metastable zone width by lowering interfacial tension and promoting burst nucleation.
- Processed NTO shows regular morphology, smaller size, and narrower size distribution.
- Ultrasound-treated NTO has improved flowability and 60% lower impact sensitivity.

## Abstract

3-Nitro-1,2,4-triazol-5-one (NTO), a well-known energetic material, is extensively employed in the field of insensitive munitions. However, its irregular crystal morphology and broad particle-size distribution hinder its wider application. Ultrasonic-assisted crystallization offers an innovative approach to enhance the overall particle performance of NTO. In this study, NTO was subjected to ultrasound-assisted cooling crystallization using water as the solvent to control the crystal size and morphology, as well as remove adhered nitric acid and ensure environmentally production. The metastable zone width (MSZW) of NTO in aqueous solution was subsequently measured to understand the nucleation kinetics, revealing a significant reduction under ultrasonic irradiation. Employing Sangwal’s three-dimensional nucleation theory, the nucleation kinetic parameters were calculated. The results indicate that ultrasound affects the MSZW through reduction of the solid–liquid interfacial tension, promotion of burst nucleation, and suppression of particle agglomeration. Characterization of the ultrasound-processed NTO demonstrated a more regular morphology, disrupted agglomerates, reduced particle size, and a narrower particle-size distribution without altering the crystal polymorph. Compared with NTO raw material, the material demonstrates enhanced flowability and a 60% reduction in impact sensitivity.