Reactive characterization of anhydrous iodine (v) oxide (I₂O₅) with aluminum: amorphous versus crystalline microstructures

Iodine pentoxide (I₂O₅) is typically synthesized by dehydration of iodic acid such that the produced material inherently includes hydrated iodic acid species that facilitate further water absorption when exposed to ambient environments. This is a detrimental property for I₂O₅ powder used in energetic systems. A dry-approach for synthesizing I₂O₅ with either crystalline (nano C I₂O₅) or amorphous (nano A I₂O₅) structure was used for this study and compared to the commercially available material. This synthesis approach enabled isolation of the microstructure as a variable to better understand water absorption behavior of I₂O₅ and associated reactivity. Material characterization included BET, SEM, TEM, and XRD as well as equilibrium analyses using DSC and TGA along with flame speeds. Results show that nano C I₂O₅ reacts less with atmospheric water and has a more anhydrous behavior than the crystalline I₂O₅ powder commercially available. The nano A I₂O₅ also produced a distinct pre-ignition reaction (PIR) and evidence for smaller PIRs are shown for all mixtures of Al with I₂O₅. These properties along with increased specific surface area of the nano C I₂O₅ and nano A I₂O increased reactivity and enhanced combustion with Al when compared with commercial I₂O₅.