Journal of the American Ceramic Society, Vol.89, No.6, 1822-1826, 2006
Nano-blast synthesis of nano-size CeO2-Gd2O3 powders
CeCl(3)(.)7H(2)O and GdCl(3)(.)6H(2)O that were dissolved in water were precipitated with urea (NH2CONH2) to produce matrix agglomerates for three-component nano-reactors. Mixing hexamethylenetetramine with dilute nitric acid resulted in the formation of well-dispersed nano-particles of cyclotrimetilene trinitramine (C3H6N6O6) (RDX) in the solvent. Nano-reactors were produced by impregnating the nano-C3H6N6O6 into the matrix agglomerates of an intermediate complex of cerium and gadolinium compounds. Blast initiation of the C3H6N6O6 resulted in extremely rapid detonation and gaseous products formation at temperatures of 2000 degrees-5000 degrees C, which were compressed into a volume nearly equal to the initial volume of each RDX nano-particle. Multiple "nano-blasts" occurred in the volume of each nano-reactor. The impact of the blast waves led to fragmentation of the surrounding matter. The evolution of a large volume of gaseous products dissipated the heat of the process and limited temperature increase, thus reducing the possibility of local sintering among the primary particles. The short-term high temperature generated during the blasts enhanced the solid solubility of the metal oxides. Uniform aggregates of 22 similar to 74 nm consisting of 6 similar to 14 nm crystallites of gadolinia in ceria solid solution were synthesized.