Carbon and graphite addition effect on the crystal structure formation and grain size of MgB2 material.

MgB2 has the potential for superconducting wire applications because it has a simple crystal structure, high current density and coherence length, and grain boundaries transparency. So, it is expected to be used as a substitute for Nb3Sn and NbTi superconducting materials in magnetic resonance imaging (MRI) applications in the health sector. The chemical doping technique to achieve the superconductivity phenomenon is considered the most effective in increasing the Jc and Hc of the MgB2 superconductor. The chemical doping technique in the form of nano carbon and graphite using the powder in sealed tube (PIST) method was carried out in this study by inserting Mg, B, and various carbon powders into a 316 stainless steel tube with the desired composition, then both ends of the tube were pressed to isolate the sample from oxidation during the sintering process. Four (4) variations of carbon doping composition in this study, i.e., variation carbon doping as much as 5 and 10 wt.%, then variation graphite as much as 5 and 10 wt.%. The effect of adding graphite and carbon nanoparticles is known through X-ray diffraction (XRD) analysis to determine the phase change and crystal structure, then observations using scanning electron microscope (SEM) to determine particle size, homogeneity, and porosity of each sample. The effect of adding of graphite and carbon nanoparticles is known through XRD analysis and observations using SEM. Analysis of the XRD results showed that the peaks formed were MgB2, and the other phases were Mg, B, C, and MgO, with an average crystal size of 38.1159, 33.5453, 28.0377, 17.0373, and 25.2136 nm. While the results of SEM observations indicate that the grains have started to become homogeneous, there is still porosity and agglomeration in some samples with an average grain size of 2.4913, 2.51926, 2.5163, 2.53742, and 2.5126 µm. [ABSTRACT FROM AUTHOR]