Ammonium Nitrate Catalyzed with Copper Chromite Nanoparticles: A Novel Halogen Free Oxidizer for a Solid Propellant with Low Smoke Signature

Ammonium perchlorate (AP), the main oxidizer for solid propellants, results in white smoke (HCl); which could induce acidic rain and could damage fertile soil.A chlorine-free oxidizer is highly valued for solid propellants.Ammonium nitrate (AN) emerges as a promising green oxidizer; however it exhibits low performance (i.e.specific impulse).The present work describes the synthesis of copper chromite nanoparticles (NPs) of 45 nm.Copper chromite NPs were synthesized through hydrothermal synthesis; the developed nanocatalyst was then integrated into an AN matrix.While virgin AN demonstrated a strong endothermic decomposition of +1707 J/g, catalyzed AN demonstrated a superior exothermic decomposition, with an enthalpy of -1492 J/g.A solid propellant formulation based on AN and copper chromite (CuCr2O4) was optimized using the Institute for Chemical Technology (ICT) thermodynamic code via partial replacement of AP with AN.AN (30 wt.%) was found to decrease the smoke signature by 54.4%, with a minimum decrease in specific impulse.The solid propellant formulation was developed via mixing and vacuum casting.The ballistic performance was assessed using a small-scale ballistic evaluation rocket motor.The AN-based formulation demonstrated a stable combustion process with a slight decrease in the characteristic exhaust velocity and total pressure impulse of 4% and