Internal reduction of (Mg, Cu)O

Abstract

(Mg, Cu)O single crystals are internally reduced at temperatures ranging from 1273 to 1673 K in the presence of either a C/CO buffer or a CO/CO₂ gas flow. As a result, a reduction scale containing discrete precipitates develops. At low reaction temperature, this scale is divided in an outer part where discrete copper precipitates are present in the MgO matrix, and an inner part where both metallic copper and cuprite Cu₂O precipitates coexist in the MgO matrix. At high temperatures, the inner scale is very narrow. Transmission electron microscopy (TEM) investigations of the reduction scale reveal special orientation relationships between the MgO lattice (m) and that of the precipitates (p):