Research Centre Karlsruhe
Karlsruhe, Germany
Scientist in Charge: Dr. Wilfried Goldacker
Expertise and experience
The Institute of Physics of the Research Centre Karlsruhe, member in the Helmholtz-Gemeinschaft, works on the development of superconductors, LTC and in particular HTS and MgB2 , the application of superconductivity in devices for energy technique as current limiters, energy storage devices (SMES), NMR magnets and new prototype high field magnets, magnets for fusion reactors and superconducting devices for space technology and the liquid hydrogen field. All R&D is implemented in projects and cooperation with industry, national research projects, virtual institutes and projects funded by the EC. Many of the enterprises are co-ordinated by the research centre. The R&D spectrum of the institute is completed by a research group for the cryogenic technology and another one is specialised for high vacuum vessels and pumping systems as adsorption and cryo-pumps.
The HTS superconductor R&D is strongly focussed on the application of superconductivity and applies a complete state-of-the-art equipment for fabricating and characterising superconducting wires in particular designed for specific applications, actually focussing on MgB2 wires and YBCO coated conductors. A special expertise is the implementation of fundamental research in the development of prototype wires for the application. For technical MgB2 wires, multifilamentary composites with thermal and mechanical reinforcement are under development. First applications in space and lH2 technology were realized with partners and new co-operations are actually under preparation. For further improvements, nano-scaled investigation and preparation work has to be done to come closer to the potential of the material. Nano-engineering means developing superconducting materials with microstructures being specified and controlled in the nanometre scale. Special aspects are pure phase, very small grains and nano scaled artificial, so-called pinning centres, which serve for trapping the magnetic flux in the superconductor. The challenge is to prepare nano-powders by innovative methods and to handle the nano-powders. For coated conductors, the fluorine-free all chemical solution deposition route on cube textured substrates is under investigation as the future low cost route. Excellent buffer and YBCO layers are already being obtained. Focussing on application in motors, transformers and coils (future fusion reactor coils), Roebel type cables for high transport currents in the > kA class and providing low AC losses were demonstrated and are under development. The development of cables is addressed to the application in fusion research and devices of the energy sector like transformers and motors. FZK has extended experience as a partner or coordinator of EU funded projects in the area of applied superconductivity (e.g. BriteEUram-Project (EU) "Development of high critical current Bi(2223) tapes", BriteEUram-Project (EU) "Development of low AC loss Bi(2223) tapes” and HIPERMAG) and a virtual institute for developing chemically prepared coated conductors (FZK + 4 universities) which has a strong interdisciplinary character and focus on education.
Role in the project
The role of FZK in the project is focussed on high amperage low AC loss cables for application in large devices and the development and optimisation of the YBCO coated conductors being used for these cables. FZK will develop the Roebel assembling technique for the coated conductors as well as the strand structuring method with CSD deposition of buffers and YBCO and applying lithographic structuring. This should end up in a well-specified technique suited for an industrial process for long lengths. AC losses and micro- and nanostructure will be investigated by means of SEM, EDX and EBSD in cooperation with the partners. Current inhomogeneity and improvement of the pinning properties will be investigated with MOI imaging of the current distribution. Cryogenic questions as cooling conditions, concepts and thermal stability of the coated conductors and cables will be investigated and will be content of a training course together with Stirling.
Key scientific staff
Dr. Wilfried Goldacker (head of superconducting materials group, cable concepts), Dr. Sonja Schlachter (MgB2 project leader, head of cryogenic lab., transport currents), Dr. Gunter Kotzyba (CC Chemistry), Dr. Rainer Nast (CC metallurgy); Dr. Curt Schmidt (AC Loss laboratory, investigations and theory)