Thermal Analysis for Nano Powders of Iron and Zinc by DSC

Nano powders (NPs) are common and frequently employed in industry, and the iron is mostly applied in high-performance magnetic materials and pollutants treatment for groundwater, and the zinc is widely used in brass, bronze, die casting metal, alloys, rubber, and paints, etc. Nonetheless some disasters induced by metal powders owing to lack of related safety information. In 2011, three metal iron dust flash fires occurred over a periods of five months and killed total of five workers in Hoeganaes Corp., USA., In fact the U.S. Chemical Safety and Hazard Investigation Board (CSB) in 2006 recommended that the Occupational Safety and Health Administration (OHSA) should issue a federal regulatory combustible dust standard for general industry, still no comprehensive OSHA standard to prevent these accidents. In this study, we first utilized differential scanning calorimetry (DSC) and applied the thermal analysis technique to evaluate thermal hazards associated with the nano iron and zinc powders, we then applied thermal analysis software to evaluate the related thermal safety information such as the exothermic onset temperature (To), peak of temperature (Tp), heat of reaction (ΔH), etc. The nano iron powder experimental results of To were 135–140 °C, 148–158 °C, and 141–149 °C for 15 nm, 35 nm, and 65 nm, respectively. As for the ΔH were larger than 3,800 J/g, 5,000 J/g, and 3,900 J/g for 15 nm, 35 nm, and 65 nm, respectively. The 100 nm nano zinc powder of To was 282 °C and ΔH was 4,262 J/g. Such safety information can benefit relevant NPs industries for preventing the accident and strengthen its protective measures and emergency response.