Enhancement of Bi2212 Powder Consistency to Support Manufacture of High-Performance HTS Wire

The Department of Energyĺs Office of High Energy Physics promotes the development of state-of-the-art particle accelerators for cutting-edge experimentation. To support these advances, improved high- temperature superconducting (HTS) wires are required in order to build high-field magnets that generate magnetic fields greater than 18 T. One key material for the development of HTS wires is Bi2Sr2CaCu2O8+x (Bi2212). Although high-performance Bi2212 wire has previously been reported, the next necessary step to support commercialization is to achieve batch-to-batch consistency of the Bi2212 powder used to manufacture the wire. In Phase I, Engi-Mat produced 15 different batches of Bi2212 powder in order to evaluate precursor composition, production settings, and processing conditions. The uniformity of the Bi2212 powder was assessed on the basis of scanning electron microscopy and subsequent image analysis. Two of the Bi2212 powder batches were then used for fabrication of HTS wire billets by Bruker OST. Following over-pressure heat treatment of the wire samples, measurements at the National High Magnetic Field Laboratory (NHMFL) indicated maximum engineering critical current densities (Je) of 1120 and 1180 A/mm2, respectively. During Phase II, Engi-Mat will produce additional batches of Bi2212 powder, leveraging the production and processing ôguidelinesö learned during the Phase I exploratory stage. The aim is to maintain a high degree of batch-to-batch Bi2212 powder consistency, while enhancing process efficiency. Bruker OST will fabricate five 2 kg HTS wire billets, which will be processed and evaluated at NHMFL. An overarching goal is to establish correlations between Bi2212 powder (uniformity and physical properties) and HTS wire performance. The development of high-field superconducting magnets based on HTS wire supports advancement in scientific research, health, and energy. Superconducting magnets are critical components of large-scale particle accelerators for experimentation to broaden our understanding of fundamental physics concepts. In the area of health, magnetic resonance imaging (MRI) instruments rely on newer and better superconducting magnets to provide higher resolution imaging for diagnostic capabilities. Lastly, the burgeoning field of fusion energy, which represents a shift away from high carbon emission energy sources, will utilize superconducting magnets in very large volumes.