Ignition and explosion characteristics of four kinds of nanopowders

Abstract

This work is about the study of ignition sensitivity and the explosion violence characteristics of nanoparticles. It was carried out on various nanopowders as part of a project (NANOGRA) that aims at a multidisciplinary assessment of the risks related to nanoparticles. This paper discusses the experimental results for the determination of ignitability and explosion violence characteristics of Thermal Black N990, Corax N550, MWCNTC7000 and partially passivated metallic nanoparticles (Aluminium). The results of the various tests (MIE, Pmax and KSt) led to the conclusion that carbon nanopowders are capable of generating, when airborne, an ATEX with moderate explosion intensity comparable to the ST1 class. They are little sensitive to electrostatic phenomena. The assessment of explosion parameters of carbon nanopowders was generally found similar to their microscopic size analogue. The pyrophoric nature of partially passivated aluminium nanopowder required screening tests (e.g. MIT layer and combustibility) to control the risk of ignition in the stages of the characterization tests. The results show that aluminium nanoparticles are sensitive to the risk of ignition by a phenomenon of electrostatic origin, and explosion violence seems to decrease when BET specific surface area increases.