Influence of Atmosphere on the Reaction Properties of Al/Zr/TiO₂ Thermites

ABSTRACT We investigate the influence of different atmospheres on the reaction of a low‐gas generating, non‐expanding thermite formulation composed of ball‐milled Al:Zr fuel and TiO 2 (anatase) oxide powders combined in a stoichiometric ratio. These thermite materials have applications as heat sources in confined geometries where gas generation and sample expansion would be detrimental. We measure burn rates, reaction temperatures, and reaction products of uniaxially compacted samples laser ignited in air, vacuum, Ar, and N 2 . Samples in the air burned close to the adiabatic reaction temperature, while vacuum, Ar, and N 2 atmospheres resulted in lower temperatures. Ar samples were quenched upon removal of the laser energy. Air, vacuum, and N 2 samples all propagated at approximately 2.2 mm/s. A two‐stage reaction front was observed in air and vacuum samples, while only a single reaction front was seen in the N 2 samples. No expansion of the compact was observed during reaction in any of the atmospheres studied. After the reaction, Al and Zr oxides were detected in all samples, with crystalline phases of the nitrides of Zr and Ti also recorded for samples ignited in N 2 .