SYNTHESIS OF HG1-XREXBA2CA2CU3O8+X PURE PHASE AT NORMAL PRESSURES

High purity ceramics of the superconducting phases Hg1-xRexBa2Ca2Cu3O8 have been prepared by the vacuum sealed quartz tube techniques. The s uperconductors were obtained using precursor powders of Ba2Ca2Cu3Ox mi xed with stoichiometric additions of ReO2 and HgO. The reaction was ca rried out in two steps: Firstly, the Ba2Ca2Cu3Ox was homogenised and a nnealed with ReO2 in oxygen atmosphere. Finally, the powders were mixe d and pressed with stoichiometric additions of HgO and were encapsulat ed in an evacuated quartz tube and annealed at different rates and tem peratures in order to optimise the purity of the phase.