Lawrence D. Woolf

High rate melt texturing of Nd1−xBa2+xCu3O7−δ type superconductors

Melt texturing is one of the most prominent techniques available to fabricate bulk high‐temperature superconductors with superior current transport and magnetic properties. In the case of Y1Ba2Cu3Ox, melt textured samples can have a Jc on the order of 105 A/cm2 at 77 K and zero applied magnetic field, and in excess of 103 A/cm2 at 77 K and 30 T. However, a serious drawback of the melt textured Y1Ba2Cu3Ox compound, which severely restricts its application, is the very slow rate (1 mm/h) needed to develop the highly textured planar front necessary for optimum superconducting properties. RE‐123 compounds containing the rare earth element neodymium have been recently found to recrystallize much more rapidly, indicating the possibility of their high speed melt texturing. By processing bars (50 mm×5 mm×5 mm) of these compounds through a high‐temperature gradient, fully textured microstructures were obtained at rates up to 50 mm/h, which are more than 50 times faster than those employed in Y1Ba2Cu3Ox. After oxyg...

Continuous fabrication of high‐temperature superconductor coated metal fiber and multifilamentary wire

Long superconductor fibers have been continuously produced by electrophoretically depositing REBa2Cu3O7−x (where RE=Y or a selected rare‐earth element) powder onto a metal substrate fiber and sintering, then electrophoretically depositing silver and sintering. After collecting the coated fiber on a take‐up spool, the entire spool is batch‐oxygenated to form the 90 K superconducting phase. Multiple fibers are then continuously unspooled and soldered into a copper channel to form the final multifilamentary high‐temperature superconductor wire. Superconducting fibers over 1000 m long and multifilamentary wire 70 m long have been produced.

Fabrication of long length Bi-2223 superconductor tape using continuous electrophoretic deposition on round and flat substrates

We have developed a continuous fabrication process for producing long lengths of Bi-2223 superconductor tapes. The process involves sequentially electrophoretically depositing and sintering superconductor and then silver layers on a substrate, followed by rolling and thermal processing. Both round and flat silver substrates have been used. Bi-2223 tapes made using flat silver substrates require only a few processing steps. Transport critical current densities at 77K in zero applied magnetic field exceeding 20000 A/cm2 have been obtained.

Multiple smatterings of insight: 10 years of interaction with Craig Bohren

Craig Bohren has enhanced science education in many ways, including email mentoring of non-scientists and scientists, informal science books, and science textbooks. I had numerous interactions with Bohren over a ten year period, and he influenced my own informal-science-education efforts, which include educational modules, science education posters, and curriculum reviews.

Fabrication of long length Bi-2223 superconductor tape using a continuous electrophoretic coating process

We have developed a unique fabrication process for producing long lengths of Bi-2223 superconductor tapes. The process uses a continuous electrophoretic coating technique for sequentially depositing superconductor and silver layers on a substrate, by heat treating and rolling steps. The process offers a number of advantages over competing techniques.<<ETX>>

Development of High Temperature Superconductor Coated Metal Fiber and Multifilamentary Wire

Long superconductor fibers have been continuously produced by electrophoretically depositing REBa2Cu3O7−x powder onto a metal substrate fiber and sintering, then eletrophoreticaly depositing silver and sintering. After collecting the coated fiber on a take-up spool, the entire spool is batch-oxygenated to form the 90 K superconducting phase. Multiple fibers are then continuously unspooled and soldered into a copper channel to form the final multifilamentary high temperature superconductor wire. Superconducting fibers over 1000 meters long and multifilamentary wire 450 meters long have been produced.