Multiscale phase homogeneity in bulk nanocrystalline high entropy oxides

X-ray diffraction, energy dispersive spectroscopy, and atom probe tomography (APT) were used to assess the phase homogeneity of bulk sintered (Cu, Co, Mg, Ni, Zn)O transition metal high entropy oxides (TM-HEOs) across multiple length scales. These three methods applied both coarse-grain nanocrystalline TM-HEO samples using two different processing routes. Coarse-grain prepared by reaction sintering unreacted nanopowders conventional sintering, while from solid-state synthesized consolidated spark plasma sintering. Despite grain sizes, exhibit little-to-no chemical or segregation all Critically, APT confirms that there is no at nm scale even after synthesis temperature consolidation.