Synthesis of YBCO/Ag powders by citrate route: effect of gas composition on thermal cycle

YBa2Cu3O7/Ag (10%wt) powders by an original variant f the citrate route were prepared. Such a technique offers the typical advantages of wet methods, doesn’t make use of nitrates, utilizes readily available reagents and guarantees good stoichiometry and homogeneity of the final powders. Furthermore, it allows for a fine dispersion of metallic silver so as to improve mechanical and transport characteristic and to obain the correct oxygen stoichiometry. After drying of the initial solutions and decomposition of the organic substance, the carbon content was reduced heating the precursor powders at high temperatures (950°C) in O2-NOx flux. In the present work, moreover, the difference of different atmosphere (oxygen and/or nitrogen) used in the final heat treatments on the YBa2Cu3O7-δ formation has been addressed. The powders so obtained were compacted to get small bars and sintered in oxygen at 920°C and characterized by XRD and susceptibility measurements.