Copper, one of the 3 elements in $YBa_2Cu_3O_{7-x}$ superconductor, is generally used as a material for power cable due to good electrical and mechanical properties. Objective of this research is to fabricate and investigate screen-printed YBCO superconductor films on Cu plates by reaction between Cu-free $Y_2O_3 & BaCO_3$ melt and Cu substrates. At first, for stoichiometry of $Y_1Ba_2Cu_3O_{7-x}$ superconductor, the mixing ratio of Y and Ba was fixed at 1 : 2, and from $Y_2O_3$, BaO and CuO ternary phase diagram, we obtained the liquid phase reaction temperature, 950℃ and 980℃. We can observe CuO and Ba-Cu oxide phases from XRD patterns of reacted samples at 950℃ and 980℃ for 3min, and from SEM images of the cross section of the samples, we can observe that reacted region was composed of 3 layers, Cu oxide/middle part/Cu oxide. Because oxidation of Cu is intensive over 900℃, CuO layer formed on the surfaces of the reacted samples.
According to EDS line scan data and WDS mapping data of the cross section of the samples, most Y and Ba existed in the middle part of the samples. For investigation of ground surface of the samples, samples were ground with SiC paper(s.c 600) with various grinding thickness, and ground surface was investigated using XRD and EDS. Differences of the phase distribution on the ground surface of the samples reacted at 950℃ and 980℃ were investigated and Tc(critical temperature) was measured by 4-point probe method about the surface existing Y123 phases. The resistance decreased rapidly before the temperature was lower than 74 K. But zero resistance was not observed possibly because of the impurity phases mixed with Y123.
