Determining metallic nanoparticle size from exploding wires

Metallic nanoparticles are used in everything from medical treatments to rocket propulsion systems. However, the most effective bulk production method of electrically exploding wires is controlled largely through experience due to the challenge of theoretically modeling the complex physical processes involved.

Wang et al. presented the first computational model of electrically exploding wires for metallic nanoparticle production. Their model bridges the gap made by other computational methods by simulating the time between wire explosion and nanoparticle growth and can predict the size distribution of nanoparticles from cold-start conditions.

During nanoparticle formation, metallic wires are heated via pulsed current until they explode. The resulting fragments are rapidly cooled by ambient gas, forming monomers that precipitate into nanoparticles. This process is highly dependent on the gas pressure, which the team took into account to accurately predict the resulting nanoparticle sizes.

“Our research presents significant new results on the modeling of electrically exploding wires that sheds light on the effect of ambient gas pressure on the formation of nanoparticles and their size distribution,” said author Kun Wang. “The predictions for the dependence of size distribution on different pressures are remarkably accurate.”

The model aims to cover the whole nanoparticle formation process from the phase transition of metallic wires to the magnetohydrodynamic behavior of exploding products and nanoparticle growth. The authors verified the model’s predictions using experimental measurements of exploding aluminum wires in argon gas under different atmospheric pressures.

“I hope that our research can provide theoretical support for the regulation and control technology in nanoparticle synthetization by electrically exploding wires,” Wang said.

The authors are continuing to research the preparation of high-entropy nanoparticles by electrically exploding multiple wires.

Source: “Understanding the effect of ambient gas pressure on the nanoparticle formation in electrically exploding wires,” by Kun Wang, Yuqing Zhang, Lincun Jiang, Zhiyuan Li, Xin Wang, Jinwei Zhai, Siao Zhang, Physics of Plasmas (2023). The article can be accessed at https://doi.org/10.1063/5.0120712 .