Sodium Azotetrazolate: A Novel Environmental-Friendly Hydrogen-Free Gas-Generating Pyrotechnics

Gas-generating pyrotechnics are widely used in airbag inflator, pre-tensioner seat belt, deep-water salvage, fire extinguishing bomb, etc. However, for maintaining prolonged high-pressure, specific gas-generating pyrotechnics are required that are capable of producing water-vapor-free gaseous products to avoid the decrease of pressure caused by the condensation of water vapor. Currently, only sodium azide (NaN3)-based gas-generating pyrotechnics can meet the demand, but its application is limited due to its toxic effects. In this work, a sodiumazotetrazolate-based (STZ-based) eco-friendly and hydrogen-free gas-generating pyrotechnics was presented. A typical STZ-based gas-generating pyrotechnics was NaNO3/STZ gas-generating pyrotechnics, which could generate 321.04 L/kg clean and non-toxic gas composed of N2 and CO2 without any water vapor. The burning characteristics, including the ignition delay, maximum pressure and burning time of NaNO3/STZ gas-generating pyrotechnics was determined by conducting a closed vessel test. NaNO3/STZ gas-generating pyrotechnics showed a stable combustion process, lower ignition delay, higher burning rate, and the maximum pressure produced is 1.7 times of that of NaN3/Fe2O3. Thus, STZ exhibited great potential as gas-generating pyrotechnics, which could be applied, especially where a stable pressure is required for a long time.