Synthesis and characterization of MgB2 superconductors with carbon nanotubes (CNTs) and tin (Sn) addition

Abstract

MgB2/CNT is a promising candidate for superconducting wire application due to its excellent mechanical properties and carbon nanotube’s low density. However, strong interfacial adhesion between the CNT reinforcement and the MgB2 matrix is difficult to manage. Therefore, this study examines the synthesis and characterization of magnesium diboride (MgB2) superconductors with carbon nanotubes (CNTs) and tin (Sn) addition. Determining the proper method and combination of CNT & Sn affects MgB2 superconductors is crucial. Raw materials of magnesium (Mg), boron (B), Sn, and multi-walled carbon nanotubes (MWCNTs) were used for a solid-state reaction process to determine the proper synthesis method and the effect of CNT on superconductors’ critical temperature. Each sample was obtained by weighing the raw material first, followed by hand grinding with agate mortars for 3 hours. The pelletization was then conducted by using a compact pressing machine with a pressure of 350 MPa. The compacted samples were then sintered at 800 °C for 2 hours either through the vacuum or PIST process. Finally, all were characterized, and MgB2 was discovered to be the dominant phase with minor impurity phases such as MgO, Mg, Mg2Sn, C, and Sn. Based on SEM morphological analysis, the grain boundaries of sample A1 were more precise than B2. In both, the grain size also varies, and the distribution of elements is uneven. Subsequently, Cryogenic Magnet Characterization indicated that at 40 K, almost all samples possess superconducting characteristics. For future studies, the potential impact of MgB2 on critical current density (Jc) and magnetic density (Hc) in several commercial applications such as Magnetic Resonance Imaging (MRI), magnetic levitation, and transformers needs to be investigated