NOVEL PROCESSING OF COATED BORON PARTICLES

SOLID METAL FUELS CAN PROVIDE GREATER THRUST AND FUEL EFFICIENCY THAN LIQUID FUELS. BORON PARTICLES, A MOST ATTRACTIVE SOLID FUEL ON A THERMOCHEMICAL BASIS, IGNITE UPON EXPOSURE TO MOIST AIR AND UNDERGO A RAPID COMBUSTION WITH HIGH VOLUMETRIC HEAT RELEASE. UNFORTUNATELY, THIS REACTION IS SIGNIFICANTLY SLOWED BY IMPURITIES IN THE BORON AND BY THE FORMATION OF OXIDES UPON THE PARTICLE SURFACE DURING THE IGNITION PROCESS. HOWEVER, IT SHOULD BE POSSIBLE TO DEPOSIT A CONTINUOUS THIN FILM OF ALUMINUM OR MAGNESIUM ONTO PURE BORON VIA CVD, ALLOWING UNIFORM PARTICLE HEATING AND IGNITION WITHOUT SURFACE PASSIVATION. A NOVEL ALUMINUM SOURCE REAGENT AND COATING PROCESS HAVE ALREADY BEEN DEVELOPED BY ATM. IN PHASE I, AN INNOVATIVE COATING TECHNIQUE WILL BE EMPLOYED ALLOWING UTILIZATION OF THIS TECHNOLOGY AND OPTIMIZATION OF THE METAL COATINGS. A SIMILAR PROCESS WILL BE DEVELOPED FOR MGNESIUM COATING OF THE SOLID FUEL AND REACTION KINETICS WILL BE EVALUATED TO ASSESS COATING EFFECTIVENESS. POSITIVE PHASE I RESULTS, INCLUDING COST ESTIMATES, WILL RESULT IN A PHASE II PROGRAM IN WHICH BORON PURITY IS ASSURED VIA IN-SITU COATING OF VAPOR DEPOSITED BORON PARTICLES. REACTION KINETICS WILL BE OPTIMIZED THROUGH COATING APPLICATION AND PILOT QUANTITIES OF METAL COATED BORON PARTICLES WILL BE PRODUCED FOR COMBUSTION TESTING.