Minimum ignition energy for micro and nano flash powders

Abstract

The minimum ignition energy (MIE) of dust clouds is required to assess the electrostatic ignition risk. Recently, the growing number of accidents shows that fire and explosions occurring in fireworks industry are due to electrostatic discharge (ESD). The objective of the this paper is to discuss the various practical concerns during the handling of flash powders of various compositions containing potassium nitrate, sulfur, and aluminum in fireworks. These powders form dust clouds and cause fires and explosions because the MIEs of these dust clouds are very low. This study is carried out with powders of various sizes ranging from micron and nanometer. The measurements are done by using a 1.2-L Hartmann apparatus. The experimental results show that the MIEs for flash powders are in the range from 89.2 to 19.8 mJ for micronand nano-sized particles. The experimental results are given for various changes, such as: electrode gap, electrode material, and dust concentration, dust composition, etc. If the nano flash powder is mixed with micron powders, the MIE is greatly reduced, and it becomes extremely combustible. Therefore, it is imperative for fireworks manufacturers, or anyone handling these dusts, to take precautionary measures to prevent fires and explosions involving ESDs.

Surface structural features and wear analysis of a multilayer Ti6Al4V-B4C thin film coated AISI 1040 steel

“…DSC analysis shows the weight gain at 825°C with micron size particle as revealed by Selvakumar and Sivaraj [11]. Moreover, nanosized aluminum powder produces high thermal energy and the thermal behavior of nanoparticles was superior as compared to the micron-sized particles as described by Azhagurajan et al [12]. In general wear resistance of the metals can be improved with hard nitride and carbide coating, which exhibits better wear resistance, low frictional coefficient and improved hardness [13,14].…”

TG/DTA studies on the oxidation and thermal behaviour of Ti-6Al-4V-B4C coatings obtained by magnetron sputtering

“…(Selvakumar, Sivaraj, & Muthuraman, 2016) discussed weight gain due to the micron size particle by DSC analysis and weight gain was identified at 825°C. (Azhagurajan, Selvakumar, & Mohammed Yasin, 2012) reported that nanoparticles expose superior thermal behaviour than micron-sized particles. Moreover, high thermal energy was created by nanosized aluminium powder.…”