MANUFACTURE OF ULTRAFINE BIPBSRCACUO POWDER BY AN IN-SITU NANOMETER REACTION PROCESS

A new method has been developed for the manufacture of the bismuth-bas ed superconductor precursor powder BiPbSrCaCuO for fabrication of high -J(c) Ag/Bi(2223) tape. The new method consists of two main stages. Fi rst, nanoparticles with specific stoichiometry are prepared in a low-s urface-tension liquid medium based on a coprecipitation reaction and i n situ dispersed in the medium to obtain a suspension. Second, the sus pension is in situ transformed into ultrafine oxide particles (similar to 200 nm) by heat treatment where each nanoparticle reacts on a nano metre scale (nanometre reaction) with the least possibility of contact and agglomeration. The new method has brought about a new process ter med an in situ nanometre reaction process (INRP). The new process can be used to manufacture finer BiPbSrCstCuO particles with a lower carbo n content in a shorter time than the traditional coprecipitation proce ss (TCP) because the agglomeration processes from filtration through d rying to calcination are omitted.