(70aw) Crystallization and Agglomeration for Coating of Energetic Materials

Abstract Energetic materials (explosives and propellants) are used extensively for both civilian and military applications. Some major considerations for successful weaponization of energetic materials include performance (e.g. energy density, rate of energy release), long term storage stability, and sensitivity to unwanted initiation. The sensitivity of explosive materials is strongly affected by crystal size, crystal shape, crystal size distribution (CSD), roughness of crystal surface, crystal perfection and crystal strength. One of the ways to lower the sensitivity towards sudden shock is to control the crystal the crystal morphology to be close to sphere. Crystallization process offers the crystals in the specifications of acceptable crystal size, crystal shape and narrow crystal size distribution. These can be optimized by selecting the right operating conditions of crystallization process. Crystallization technology is wildly used for the production of high-value bulk pharmaceutical chemicals and chemicals, especially in size and shape control of particles and in separation and purification processes. Unfortunately, only few researchers have applied this process to achieve coatings. The aim of this study is to examine how a crystalline coating can be formed by solution crystallization and how a operating conditions affect to the surface morphology and the crystal growth rate of the HMX coating. Here experimental conditions are solvent types, concentration of NTO-solutions, the degree of subcooling, the operating time and the agitation speed. Moreover, crystallization coating is shown to occur by an agglomeration mechanism. Finally the sensitivity of HMX coated with NTO is examined.

Key words: crystallization, coating, agglomeration, energetic materials, crystal growth