| Abstract Scope |
High entropy spinel ceramics, such as (Co,Cu,Mg,Ni,Zn)Fe2O4, allow investigation into the relationship between complex compositions, multi-cation lattices, crystal structure, phase state, microstructure, and properties. The application of post-consolidation heat treatments at select temperatures and times can yield variations in the phase evolution of these complex spinel oxides, similar to what has been previously observed in high entropy rocksalt oxides. We use solid-state synthesis methods, such as conventional sintering and spark plasma sintering (SPS), to synthesize fully dense, bulk samples. X-ray diffraction (XRD) is used to evaluate the variations in phase heterogeneity, while grain morphology and size are examined using scanning electron microscopy (SEM), both as a function of post-consolidation heat treatments. X-ray photoelectron spectroscopy (XPS) is used to determine the changes in the cationic valence states and arrangement of the spinel crystal structure(s). Changes in phase state and microstructure are anticipated to strongly influence mechanical and electrical behavior. |