New second-generation high temperature superconducting coated conductors (2G HTS CC) with greatly-improved thermal stability

与前几代商业超导线材在4.2K附近需要昂贵的液氦制冷剂不同，第二代高温超导涂层导线(2G HTS CC)只需要77K下廉价的液氮作为冷却剂。因此，制冷管理成本至少低了20倍；这项技术正准备进军电力行业，这是一个每年近万亿美元的市场。这项提议涉及的一个特殊应用是超导故障限流器(FCL)，这是一种针对全球超载电网的安全设备。不幸的是，目前可用的基于YBCO(稀土铜酸盐)的2G高温超导CC带有一个重大障碍，即在超导到正常失超事件期间有形成破坏性“热点”的危险。这项拟议研究的目的是帮助解决这一缺点：我们最近证明，故意引入“分流器”(以超导体和外部正常金属稳定器之间高阻界面的形式)可以极大地(约30倍地)提高正常区传播速度(NZPV)。由此产生的“猝灭”(超导电性的突然丧失)在整个超导体体积中变得均匀，极大地减少了可能出现的热点，从而防止了磁带和设备的损坏。我们提出了几种引入流动转向器的方法，基于表面修饰或沉积电阻薄膜，例如P掺杂纳米硅(nc-Si：P)。显然，2G HTS CC制造商成功实施的先决条件必须是在现有的大批量(公里/天)制造工艺中轻松添加新步骤(S)。申请人已经为他们的发明提交了临时专利申请，合作伙伴是爱科尔理工学院的商业化合作伙伴Gpose Univalor，L.P.，后者将协助这项新技术最终向2G高温超导CC胶带生产商进行商业许可。安大略省的一个潜在用户支持当前的I2I提议，因为它计划在他们的产品中实施这一提议。

Unlike earlier generations of commercial superconducting wires, which require expensive liquid helium refrigerant near 4.2 K, second-generation high temperature superconducting coated conductors (2G HTS CC) merely need cheap liquid nitrogen at 77 K as the coolant. The refrigeration overhead costs are therefore at least 20 times lower; this technology is poised to invade electric power industries, an annual market place of close to a trillion dollars. A particular application addressed by this proposal is the superconducting fault current limiter (FCL), a security device for overloaded electric power grids world-wide. Unfortunately, currently available commercial "YBCO" (rare-earth cuprate)-based 2G HTS CC tapes have a major handicap, namely the danger of developing destructive "hot-spots" during a superconducting-to-normal quench event. It is the aim of the proposed research to help resolve this shortcoming: we have recently demonstrated that deliberately introducing a "flow diverter" (in the form of a highly-resistive interface between the superconductor and the outer normal metal stabilizer) has the effect to greatly (ca. 30-fold) enhance the normal zone propagation velocity (NZPV). The resulting "quench" (sudden loss of superconductivity) thereby becomes homogeneous throughout the volume of the superconductor, greatly reduces the possible appearance of hot spots, and thus prevents destruction of the tape and the device. We propose several approaches for introducing a flow diverter, based on surface modification or on the deposition of resistive thin film coatings, for example P-doped nano-crystalline silicon (nc-Si:P). Evidently, a prerequisite for successful implementation by the manufacturers of 2G HTS CC must be ease of adding the new step(s) into existing high-volume (km/day) fabrication processes. The applicants have filed a provisional patent application on their invention, in collaboration with Gestion Univalor, L.P., the commercialization partner of École Polytechnique, who will assist in eventual commercial licensing of this new technology to 2G HTS CC tape producers. A potential user based in Ontario is supporting this current I2I proposal, as it plans to implement it in their products.