HTS Production
- Metal Oxide Technologies, in collaboration with the Texas Center for Superconductivity (TcSUH) and the Space
Vacuum Epitaxy Center (now the Center for Advanced Materials a NASA commercialization center), both at the University of Houston, has developed a revolutionary YBCO coated conductor high temperature superconducting wire production system. A photograph of MetOx's operational Single Pass prototype production system is shown after the production of a 15 meter YBCO coated conductor wire.
This system represents the only truly continuous coated conductor processing capability know to us in the world. The MetOx system produces fully operational coated conductor tape in a single pass, starting from as-deformed or textured annealed metallic substrate produced at our commercial rolling mill partner. The primary elements, shown in the following isometric drawing are discussed below. Stabilization and insulation are the final steps to make a complete wire product.
The MetOx air-to-air, reel-to-reel, tape transport system reduces handling and improves process cycle time by virtue of its constant speed and constant tension control. In addition the simple variable speed motor control system allows controlled, high speed (currently 5 m/hr) operation with immediate scaling to over 1 Km tape length - dependent only on reel diameter.
The MetOx 100% low vacuum process eliminates the requirement for high vacuum equipment and a clean room environment. The MetOx modular system design provides for ease of process modification and line expansion. Substrate pretreatment and texture annealing are in line with
the deposition process reducing the potential for handling damage. Post- deposition tetragonal-orthorhombic phase anneal and silver stabilizer anneal are also in line.
The MetOx modified metal organic chemical vapor deposition of buffer and YBCO film provides a proven high rate (~1mm/min) and high performance (>1MA/cm2) on thick (5mm) films. MetOx single precursor technology ensures stoichiometry and uniformity, optimizes material utilization and enables easy scale up. In addition, the process benefits from a wide deposition area (2cm prototype and 20cm production system) and ease of scale up through reactor addition. Radiation heating simplifies the system and minimizes energy requirements.
The MetOx in-line process control, currently implemented for tape transport and precursor feed, ensures stable operation and uniform properties. Real time logging of all process and operating variables insures rapid understanding of how process changes affect system reliability and end product coated conductor quality.
MetOx believes, based on our review of processing plans and systems in the U.S., Europe and Asia, that this system represents the lowest possible capital cost approach to YBCO coated conductor fabrication, affecting the largest cost driver in projected complete wire costs. The system is furthermore very compact, allowing parallel systems to be installed and operated in a small manufacturing footprint. The capacity of the pictured prototype system is 5,000 kA-m/yr, scalable to a production capacity of 1,500,000 KA-m/yr. The system and processes are the subject of 23 U.S. and foreign patent applications, with additional intellectual property in progress.