Low Cost, High Performance Superconducting Cable via CCVD

For the past eleven years, researchers have been investigating possible applications of high temperature superconductors and working to solve the problems that must be overcome to yield practical superconductor technology. One area of interest is the coated superconductor cable which consists of a flexible metal substrate, a protective buffer layer, and the superconducting layer. Short lengths of these coated conductors have been made yielding critical current densities (Jc) of 1MA/cm2, but the problem arises when trying to scale the conventional deposition processes up to accommodate long lengths of wire. Also, low interaction with magnetic fields is needed for many applications down to 77K.Combustion chemical vapor deposition (CCVD) is a low-cost, open atmosphere deposition that has the potential of depositing buffer layers and the superconductor YBCO onto metal substrates in continuous reel-to-reel production. CCVD does not use costly vacuum systems required by conventional techniques, while the coating quality rivals and even exceeds that of conventional methods. CCVD coatings can be smooth, dense, and epitaxial. In Phase I, we will investigate CCVD deposition of ~50nm textured buffer layers, such as CeO2 and SYZ, onto textured reduced magnetic substrates provided by Oak Ridge National Laboratory,. These buffers are key component layers of coated superconductor technology. We will demonstrate the quality and performance of Phase I CCVD buffer layers through subsequent CCVD deposition of YBCO superconductor layers. The optimized CCVD process will be demonstrated in a reel-to-reel production mode, using polycrystalline substrates. The most promising Phase I textured coated conductor samples will be sent to ORNL for testing and evaluation.