Ignition of Aluminum Particles Coated by Nickel or Iron: Studies Under Normal and Reduced Gravity Conditions

Metal-CO2 Propulsion for Mars Missions: Current Status and Opportunities

“…The noticeable exothermic reaction between the Ni shell and Al core starts after melting of Al (melting point 933 K) and triggers the ignition [74][75][76][77][78][79]. Experiments with single Nicoated Al particles levitated in air have shown that as little as 3 wt % Ni is required to achieve the maximum (by a factor of 4) decrease in ignition delay time [77].…”

“…In CO 2 environments, Ni-coated Al particles ignite after several consecutive phase transformations in the surface layer, at a temperature 1600 K [78], i.e., at significantly lower temperature than original, oxide-coated Al particles. Very recently, experiments with iron-coated Al particles have shown that such particles ignite at a surface temperature 1600-1700 K and hence could also be used for propulsion applications [79]. Finally, it is worthwhile to investigate nonmetal coatings, such as fluorinecontaining polymers [80][81][82] and complex fluorides [83], as methods to facilitate ignition of Al particles in CO 2 atmosphere.…”