Study on the ultrafine particles of high-Tc Bi-Pb-Sr-Ca-Cu-O ceramics synthesized by a oxalate gel route

Ultrafine particles of high-Tc Bi-Pb-Sr-Ca-CuO ceramics were synthesized by an oxalate route. Several possible mechanisms in the ultrastructure processing were suggested and confirmed by Fourier transformed infrared spectroscopy. Fractal structure found in such oxalate aggregates was apparently affected by aging temperature and ionic strength of the bulk sol, which illustrated two distinct mechanisms of colloidal cluster growth processes, i.e., the diffusion-limited and reaction-limited aggregation. Moreover, the restructuring of fractal aggregates induced by ultrasonic agitation is also reported