Effect of pH on the production of dispersed Bi4Ge3O12 nanoparticles by combustion synthesis

Bismuth germanate ceramic scintillator (Bi4Ge3O12) was produced by combustion synthesis (SHS), and the influence of the synthesis parameters on the crystalline phases and agglomeration of the nanoparticles was studied. The synthesis and sintering conditions were investigated by thermal analysis, XRD as function of temperature, dilatometry and SEM. Well-dispersed Bi4Ge3O12 powder was accomplished by the combustion of the initial solution at pH 9, followed by low temperature calcination and milling. Sintered ceramics had a relative density of 98% and a single crystalline Bi4Ge3O12 phase. The luminescent properties of the ceramics were investigated by photo- and radio-luminescence measurements and reproduced the typical Bi4Ge3O12 single-crystal spectra when excited with UV, beta and X-rays. The sintered ceramics presented a light output of 4400 photons/MeV. 21 refs.