Preparation and characterization of ultrafine RDX

This paper describes the synthesis of ultrafine Hexogen (UF-RDX) of size <5μm by drowning-out crystallization. RDX was precipitated from acetone or dimethylformamide (DMF) solution by reducing the solvent power using either a miscible, non-aqueous antisolvent, n-hexane, or an aqueous antisolvent, water containing polyethylene glycol (PEG). Process parameters such as solvent/ antisolvent ratio, agitation, ultrasonication etc. were studied. UF-RDX was characterized for Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and sensitivity tests. In the case of the non-aqueous antisolvent, the precipitated RDX crystals were rod shaped of diameter <1 μm. For the aqueous antisolvent, oval shaped crystals (<5 μm) were precipitated. UF-RDX was found to be more sensitive to impact and less friction sensitive compared to production grade RDX (60-80 μm)

Formation of Boric Acid by Surface Oxidation of Amorphous Boron Powder: Characterization and Quantitative Estimation

Amorphous Boron Powder (ABP) is used as a fuel in air breathing propulsion systems due to its high gravimetric and volumetric heat value. ABP is sensitive to air and undergoes slow oxidation during storage and handling, leading to the formation of a boric acid layer on the particle surface. This paper describes an analytical method for the estimation of boric acid in ABP. In-house samples obtained from the pilot plant of this laboratory, as well as commercial samples, were assayed for their boric acid content. The study is substantiated by characterization of the ABP samples by SEM with EDX and FTIR. The ageing characteristics of in-house boron powder was also studied

Preparation of Nano Aluminium Powder (NAP) using a Thermal Plasma: Process Development and Characterization

A bottom up approach for the preparation of Nano Aluminium Powder (NAP) using a Transferred Arc Thermal Plasma Reactor (TAPR) is described. The aluminium block is subjected to evaporation by the application of a thermal plasma. The aluminium vapour produced is rapidly quenched to room temperature resulting in crystallization of the aluminium vapour in nano-particulate form. Various process parameters, such as the plasma torch power, reactor pressure and plasma gas composition were optimized. This paper also describes the characterization of NAP by analytical methods, for the estimation of the Active Aluminium Content (AAC), Total Aluminium Content (TAC), XRD, bulk density, BET surface area, HR-TEM etc. The results are compared with those for samples prepared in other thermal plasma reactors, such as the DC Arc Plasma Reactor (DCAPR) and the RF Induction Thermal Plasma Reactor (RFITPR), and for commercially available NAP samples (ALEX, prepared by the EEW technique)