Tetiana Prikhna

Abstract:

A comprehensive investigation of the structural, superconducting and mechanical characteristics of MgB2-based bulk materials and melt-textured (MT) -YBCO, prepared under different pressure-temperature-time conditions, establishes correlations responsible for attaining high functional properties of the superconducting materials and fields of their effective application. The analysis of MgB2 and MT-YBCO from the point of view of their application in inductive fault current limiters and electrical machines showed the competientability of both MgB2 and MT-YBCO materials. The advantages and disadvantages of the both materials are discussed.
A successful development of hydrogen as an energy carrier involves the transportation of liquid hydrogen over long distances. This would provide a widely available coolant for superconducting materials that operate efficiently at 20 K. Very promissing are MT-YBCO and MgB2-based materials. MT-YBCO can create higher magnetic fields but its preparation takes much longer and is rather complicated and expensive. Microcraking during oxygenation of the Y123 structure may lead to the appearance of hot sports during the operation of electrical devices. Oxygenation under high oxygen pressure and high temperature reduces the process duration and cracking hence leading to an increase of the critical current density and a reduction of the material anysotropy. The mechanical characteristics increase as well. The drawback of MgB2 ceramics can be its high sensitivity toward flux jumps, particularly reducing shield of AC magnetic fields. Manufacturing under high pressure results in dense MgB2 ceramics with a high mechanical perfomance. Both materials are promising for practical applications but futher reseach activity shoud be performed to undestand the mechanisms of their unique properties.