Hexammine metal perchlorates as energetic burning rate modifiers

Four transition metal hexammine perchlorates namely, [Cu(NH3)6](ClO4)2, [Co(NH3)6](ClO4)2, [Ni(NH3)6](ClO4)2 and [Zn(NH3)6](ClO4)2 have been prepared, characterized and used as ballistic modifiers in the combustion of hydroxy terminated polybutadiene (HTPB)-Ammonium perchlorate (AP) composite solid propellants. Burning rate was considerably enhanced with [Co(NH3)6](ClO4)2 and [Cu(NH3)6](ClO4)2 whereas moderately with [Ni(NH3)6](ClO4)2 and [Zn(NH3)6](ClO4)2 at low concentration (2% by wt). [Co(NH3)6](ClO4)2 was found to accelerate the burning rate by three fold at two percent concentration and it can be exploited as potential energetic burning rate modifier for HTPB-AP propellants. Further, ignition delay studies showed that the deflagration of propellants and AP was accelerated by these additives.