Formation of MgB2 at low temperatures by reaction of Mg with B6Si

TL;DR

This study demonstrates that MgB2 can be synthesized at relatively low temperatures through ternary reactions involving Mg, B6Si, and Mg, with analysis confirming the phase purity and the role of Si.

Contribution

It introduces a low-temperature ternary synthesis method for MgB2 using Mg and B6Si, showing improved reaction completeness and phase formation.

Findings

MgB2 formed at temperatures as low as 450°C

Ternary reactions produce more complete MgB2 than binary

Si does not incorporate into MgB2 phase

Abstract

Formation of MgB2 by reactions of Mg with B6Si and Mg with B were compared, the former also producing Mg2Si as a major product. Compared to the binary system, the ternary reactions for identical time and temperature were more complete at 750 C and below, as indicated by higher diamagnetic shielding and larger x-ray diffraction peak intensities relative to those of Mg. MgB2 could be produced at temperatures as low as 450 C by the ternary reaction. Analyses by electron microscopy, x-ray diffraction, and of the upper critical field show that Si does not enter the MgB2 phase.