Fabrication of 42-Filaments PIT-Processed MgB2 Superconducting Wire With TaB2 and SiC Addition

Abstract

The high values of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> intrinsic properties, such as the upper critical magnetic field (40 T) and critical temperature (39 K), creates the possibility to use this material for applications in high fields, also due to the low cost of the raw materials. The goal of this paper is to describe a route to produce a 42-filaments MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> superconducting wire, from the preparation of the primary powders to the final heat treatment of sinterization. TaB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and SiC are mixed with the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> powder in an attempt to enhance the flux pinning and the material's transport capacity. The MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> + additions powder was prepared using high-energy ball milling to mix and refine the grains, and then it was packed inside niobium and MONEL (Cu-Ni) tubes, using the powder-in-tube technique. The final superconducting wire is composed by 42 filaments of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> +additions. The characterization of the samples, heat treated in different temperatures and times, show the microstructure, phase distribution, and microhardness in their cross sections, along with some superconducting properties and characteristics.