Study of the Heat Treatment Profiles Applied to a Multifilamentary MgB2 Superconducting Wire

MgB
₂
is a strategic material for practical application, due to the high values of its superconducting parameters. Cables, wires, and tapes can be produced making use of the MgB
₂
superconductor. For wires, long lengths and homogeneity are necessary for the applicability of this material. The heat treatment is one of the most important steps to homogenize the MgB
₂
along the entire length. In preview works we developed a multifilamentary superconducting wire with addition of AlB
₂
-type impurities and a simultaneous carbon source. The final wire is composed of 42 MgB
₂
-filaments with average diameter of 200  μm and a diffusion barrier with thickness around 50  μm. Due to the low dimension of its parameters, a specific heat treatment profile is required. In the present work we present detailed study of the heat treatment profiles used for MgB
₂
superconducting wires around the world and applied these concepts to our multifilamentary wire, in an attempt to optimize the microstructural characteristics. Several different profiles of heat treatment were applied for this wire, and some characterizations were performed to analyze the influence of the heat treatment on the microstructural properties. As a result, the methodologies were satisfactory, presenting good options of heat treatment for superconducting wires with micrometer-size filaments.