Synthesis, Elastic Properties, and High-Temperature Stability of Multicomponent Spinel Oxide

Reports on unique properties achieved with high-entropy alloys have motivated the application of the multicomponent approach to oxide materials. We have applied this methodology to an alumina-based spinel oxide, resulting in the synthesis of polycrystalline (Mg1/5Ni1/5Co1/5Cu1/5Zn1/5)Al2O4. Samples were made by the polymeric steric entrapment technique and uniaxially hot-pressed to obtain dense pellets. Resonant ultrasound spectroscopy was used to evaluate the elastic behavior, allowing for a direct comparison of the mechanical properties of the multicomponent spinel to those of traditional MgAl2O4. High-temperature X-ray diffraction was used to investigate the high-temperature phase stability and thermal expansion behavior of (Mg1/5Ni1/5Co1/5Cu1/5Zn1/5)Al2O4.