Synthesis and formation process of LaxY1-xBa2Cu3Oy powder by aqueous chelate-mix technique
Inagaki Masahiko; Ozawa Masakuni; Suzuki Suguru
Abstract:LaxY1-xBa2Cu3Oy powders were synthesized by the aqueous chelate-mix technique using ethylenediamine tetra acetic acid (EDTA), nitrilo tri acetic acid (NTA) and imino di acetic acid (IDA) as chelating agents. The intermediate products obtained in each formation process were investigated by thermogravimetry, X-ray diffraction technique and infrared spectroscopy. It was found that the formation of the 123 phase from precursor gel proceeds in the following four steps; (1) decomposition of ammonium acetate and Cu EDTA and formation of metal copper at 120 - 220 deg., (2) decomposition of carboxyl group of chelate at 340 - 410 deg., (3) combustion of the residual organics and formation of BaCO3 and other oxides at 410 - 480 deg., and (4) decomposition BaCO3 and formation of 123 phase around 800 degree. Key Words:oxide superconductor, synthesis, shelate complex, rare earth, powder