Wires made out of high temperature superconductors offer many advantages for energy applications because of their high current density. They can be manufactured using many different architectures and methods. On approach is to use MgO buffer layers made by inclined substrate deposition on metal substrates and vapor deposited GdBaCuO films. Recent progress in manufacturing technology at our company resulted in Ic values above 500 A/cm on several 100 m long tapes which now can be produced in a pilot production line. On short samples it was already shown that even 1000 A/cm can be reached with this type of conductor . Results of normal production tapes will be shown and further possible improvements discussed.
For most real applications the tapes have to be stabilized by an additional layer of copper e.g. using electroplating. This additional copper layer also serves as a chemical and mechanical protection during coil winding and soldering processes.
In addition to the critical current, several further requirements must be considered:
One mayor demand is that the additional copper has a uniform thickness. Any so-called dog boning at the edges is to be avoided as it will decrease the packing density and lead to possible voids in coils and cables made of stacked conductors. We will show our recent progress with copper plated conductors towards a smaller thickness variation.
Also, the influence of a heat treatment e.g. during a soldering process must be considered in order to avoid any degradation during the later processing. We measured the Ic degradation during a heat treatment with typical soldering temperatures to determine the influence on the properties.
Further requirements are stress and strain tolerance or bending radius which also will be discussed for our conductors.