볼 밀링 후 방전플라즈마 소결법에 의해 제조된 MgB2의 상 분석

Abstract

This paper deals with the phase analysis of MgB₂ bulk using spark plasma sintering process after ball milling. Mg and amorphous B powders were used as raw materials, and milled by planetary-mill for 9 hours at argon atmosphere. In order to confirm formation of MgB2 phase, DTA and XRD were used. The milled powders were fabricated to MgB₂ bulk at the various temperatures by Spark Plasma Sintering. The fabricated MgB2 bulk was evaluated with XRD, EDS, FE-SEM and PPMS. In the DTA result, reaction on formation of MgB₂phase started at 340℃. This means that ball milling process improves reactivity on formation of MgB₂ phase. The MgB₂, MgO and FeB phases were characterized from XRD result. MgO and FeB were undesirable phases which affect formation of MgB₂ phase, and it's distribution could be confirmed from EDS mapping result. Spark Plasma Sintered sample for 5 min at 700℃ was relatively densified and it's density and transition temperature showing superconducting property were 1.87 g/cm³ and 21K.