Improved Insulation Coatings for Bi2212 Round Wire

Electrical insulation coatings are a preferred alternative to former ceramic wound or braided fiber insulation for Bi2212 round wire in HEP superconducting magnets due to their being 10x thinner giving higher packing factors and current densities), lacking any ill effect on superconductor performance, and having much better heat conductance reducing the likelihood and consequences of unintentional quench). These are applied as green ceramic coatings, and become all-ceramic layers during the Bi2212 reaction heat treat. While enabling a record high field of nearly 34 T in a superconducting magnet point to their benefits, remaining issues with the wire coatings include limited green state scrape resistance, cracking after heat treat, limited dielectric strength, and need for improved thickness control. The aim of the proposed program will be to address improvements in the insulation coating materials and in the coating application process enabling an insulation fully meeting the requirements for HEP as well as fusion, NMR, etc.) magnets employing round wire Bi2212. The proposed effort will address a) increased toughness of the green coating, b) investigation of the cause and elimination of cracking and spalling of the heat treated coating, c) coating application process improvements enabling better thickness control, better quality, coating piece lengths of at least a kilometer, and cost reduction, and d) investigation of the use of alternative ceramic powders enabling higher breakdown strengths. Development of an improved and qualified insulation under this SBIR/STTR program will enable nGimat, the pioneer of this technology, to establish itself as a reliable long-term commercial provider of the insulation in necessary lengths and at affordable price. nGisulate wire-insulation coatings will find immediate application in superconducting magnet- wire that are used to build magnets for major high-energy physics projects around the world. In addition, as the price of the insulation comes down, commercial applications such as Magnetic Resonance Imaging MRI) systems and subsequently automotive wire are also expected to adopt nGisulate technology.