Studies on lead-free initiators: synthesis, characterization and performance evaluation of transition metal complexes of carbohydrazide.

Cobalt, nickel and zinc tris(carbohydrazide) perchlorates (CoCP, NiCP and ZnCP) as well as copper bis(carbohydrazide) perchlorate (CuCP) of desired morphology and bulk density (0.85-0.95 g/cm3) have been synthesized during this work. The synthesis was carried out by addition of the aqueous solution of cobalt/nickel/copper/zinc perchlorates to the aqueous solution of carbohydrazide. The products were characterized by the metal content analysis and FTIR. The IR spectra and ESCA brought out the coordination of both the end amino groups of carbohydrazide with the central metal ion. Differential thermal analysis (DTA) curve indicated that CoCP, NiCP and ZnCP are thermally stable in the temperature range of 220-285 degrees C, unlike CuCP (120 degrees C). The activation energy determined by TG measurements was found to be 140-180 kJ/mol for CoCP, NiCP and ZnCP. Sensitivity data revealed their sensitivity to friction stimuli (1 kg). Impact sensitivity test results corresponded to h50% of 50-60 cm with the exception of CuCP (h50%, 11 cm). In order to assess the performance as detonants, the selected compounds were detonated on a lead witness plate of 3 mm thickness using fuse wire as well as evaluated in conjunction with tetryl in detonator No. 27 tube. The results obtained in terms of extent of damage to witness plate were on par with the standard detonator No. 27 containing azide, styphynate and aluminium metal (ASA) composition.