The effect of processing conditions on the properties of spray dried Nd1Ba2Cu3Oy/Ag composite superconductors

The aim of this study is to process Ag-doped Nd1Ba2Cu3Oy (NBCO) powders using spray drying and consequent calcinations and sintering. The influence of sintering conditions on the microstructure and superconductivity is investigated using thermal analysis (TG-DTA), X-ray diffractometry (XRD), Scanning electron microscopy (SEM), susceptibility and resistivity measurements. During sintering, a low oxygen partial pressure (1% O2/Ar) was necessary to avoid Nd for Ba substitution. Sintering was performed at temperatures ⩾990 °C. After annealing in pure oxygen, superconducting material exhibiting Tc=95 K was obtained. The addition of Ag whiskers led to improved grain growth and decreased intergrain contact in the superconducting phase. Negligible structural and morphological interaction between NBCO and Ag was observed.