Pre-sintering effects on the critical current density of YBCO bulk prepared by infiltration method

Y2BaCuO5 (Y211) pre-forms with various pore densities were prepared by sintering at various temperatures (900–1200 °C) in air. The prepared Y211 pre-forms were reacted with Ba3Cu5O8 to form YBa2-Cu3O7−y (Y123) phase by an infiltration method. Ba3Cu5O8 pellets were placed at the bottom of the Y211 pre-forms, heated above the peritectic temperature of Y–Ba–Cu–O and then slowly cooled to 980 °C. It was found that the increase of the sintering temperature significantly affected the final pore density and its distribution in the infiltrated Y123 samples. The critical current density (Jc) at 77 K of the samples prepared at higher sintering temperatures was higher than that of the samples prepared at low sintering temperatures. It is concluded that the control of pore size in sintered pre-form is important for producing a homogeneous microstructure regarding the pore and Jc.