In-situ high energy synchrotron X-ray diffraction investigation of the MgB2 phase formation and MgB2 tapes sintering

TL;DR

This study uses in-situ high-energy X-ray diffraction to analyze MgB2 phase formation and sintering in superconducting tapes, revealing low-temperature synthesis and microstructure effects on performance.

Contribution

It provides new insights into MgB2 formation at low temperatures and the influence of thermal treatments on microstructure and superconducting properties.

Findings

MgB2 forms at 300°C, much lower than typical synthesis temperatures.

Microstructure depends on thermal treatment, affecting critical current.

In-situ analysis reveals phase evolution during sintering.

Abstract

In the present paper we report an in-situ high-energy X-ray diffraction analysis of MgB2 tapes during the preparation process. The experiment was performed in a specifically designed furnace working in reducing atmosphere, compatible with the Laue diffraction condition. The MgB2 synthesis was realized starting from MgH2 and amorphous B in powder form as precursors, varying reaction temperature and testing different cooling processes. We analyzed both the MgB2 synthesis and the sintering process of tapes prepared with these powders. Phase evolution, micro and crystallographic structure were monitored during the different thermal treatments. Among the main results we observed the formation of MgB2 at an extraordinary low temperature (300C), probably as a result of a solid-state reaction between MgH2 and B. Furthermore, we studied the dependence of the micro-structure upon the thermal treatment and its effect on the critical current performance of the superconducting tapes.