Creating Reactivity with Unstable Endmembers using Pressure and Temperature: Synthesis of Bulk Cubic Mg0.4 Fe0.6 N.
Alloy and nitride solid solutions are prominent for structural, energy and information processing applications. There are frequently however barriers to making them. We remove barriers to reactivity here using pressure with a new synthetic approach. We target pressures where the reasons for cubic endmember nitride instability can become the driving force for cubic nitride solid solution stability. Using this approach we form a novel rocksalt Mg0.4 Fe0.6 N solid solution at between 15 and 23 GPa and up to 2500 K. This is a system where, neither an alloy nor a nitride solid solution form at ambient conditions and bulk MgN and FeN endmembers do not form, either at ambient or at high pressure. The new nitride is formed, by removing endmember lattice mismatch with pressure, allowing a stabilizing redistribution of valence electrons upon heating. This approach can be employed for a range of normally unreactive systems. Mg, Fe and enhanced nitrogen presence, may also indicate a richer reaction chemistry in our planets interior.
School of Engineering, University of Edinburgh, Kings Buildings, Mayfield Road, EH9 3FB, Edinburgh (UK) http://www.homepages.ed.ac.uk/gserghio/. george.serghiou@ed.ac.uk.
George
G
Serghiou
Unité Matériaux et Transformations, UMR CNRS 8207, Université Lille 1, Villeneuve d'Ascq, 59655 Lille (France).
Gang
G
Ji
School of Geosciences, The Grant Institute, University of Edinburgh, Kings Buildings, West Mains Road, EH9 3JW, Edinburgh (UK).
Nicholas
N
Odling
Helmholtz-Zentrum Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam (Germany).
Hans J
HJ
Reichmann
Université Lille 1 and Ecole Nationale Supérieure de Chimie de Lille, Villeneuve d'Ascq, 59655 Lille (France).
Jean-Paul
JP
Morniroli
Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, 20015 (USA).
Reinhard
R
Boehler
Bayerisches Geoinstitut, Universität Bayreuth, 95540, Bayreuth (Germany).
Dan J
DJ
Frost
European Synchrotron Radiation Facility, 38043 Grenoble (France).
Jonathan P
JP
Wright
Helmholtz-Zentrum Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam (Germany).
Bernd
B
Wunder
angle-dispersive X-ray diffraction; nitrides; precession electron diffraction; pressure and temperature; reactivity