Nucleation kinetics in spherulitic crystallization of explosive compound: 3-nitro-1,2,4-triazol-5-one

Nucleation kinetics of spherulitic crystallization of explosives 3-nitro-1,2,4-triazol-5-one (NTO) in N-methylpyrrolidone(NMP)+water are explored. The influence of the solvent composition upon the metastable zone width and morphologic characteristics of the crystalline NTO was also assessed. Experimental data showed that the metastable zone width of NTO solutions increases with the NMP content in the solvent. The metastable zone width increases with increasing the cooling rate and with decreasing saturation temperature. The order of nucleation in the spherulitic crystallization of NTO ranges from 1.6 to 2.8 and appears to be dependent on the saturation temperature and the solvent composition. Primary nucleation acted in the spherulitic crystallization of NTO. Induction period for nucleation was measured at different levels of supersaturation in various solvent compositions, and was used to calculate interfacial energy. The interfacial energy obtained from nucleation experiments depends on solvent composition and temperature.