Synthesis and crystallization of (Co, Cr, Fe, Mn, Ni)3O4 high entropy oxide: The role of fuel and fuel-to-oxidizer ratio

The main object of this study is to synthesize (Co, Cr, Fe, Mn, Ni)3O4 high-entropy oxide through the solution combustion synthesis (SCS) method in the presence of different fuels at various fuel-to-oxidizer (F/O) ratios. Differential thermal analysis (DTA) and in-situ high-temperature XRD (HT-XRD) results demonstrated the high degree of thermal stability of the synthesized powder up to 1100 ​°C. According to XRD results, the single-phase high-entropy oxide was crystallized at fuel-lean conditions without any heat treatment. However, the single-phase high-entropy oxide was crystallized in all samples when they were heat-treated at 600 ​°C. X-ray photoemission spectroscopy (XPS) analysis and elemental-mapping analysis results clarified the high homogeneity of the obtained powder. Statistical analysis of results revealed a direct correlation of F/O, crystallinity, crystallite size, and lattice distortion values with magnetization saturation (Ms). Besides, the data represent an indirect correlation between micro-strain and Ms. The highest amount of Ms (14.6 emu/g) was obtained for the synthesized sample with a lattice distortion of 10.28%. Moreover, a specific surface area (SBET) value of 121 ​m2/g was obtained. In summary, the results indicated the significant role of fuel type and F/O ratio in improving the physicochemical properties of SCS synthesized (Co, Cr, Fe, Mn, Ni)3O4 high-entropy oxide. The main object of this study is to synthesize (Co, Cr, Fe, Mn, Ni)3O4 high entropy oxide through the solution combustion synthesis (SCS) method in the presence of different fuels at various fuel to oxidizer (F/O) ratios. The results indicated the significant role of fuel type and F/O ratio in improving the physicochemical properties of SCS synthesized (Co, Cr, Fe, Mn, Ni)3O4 high-entropy oxide. [Display omitted] •SynThesizing (Co, Cr, Fe, Mn, Ni)3O4 high entropy oxide with different fuels at F/O.•Thermodynamic invistigation of fuel and F/O roles in the synthsized high entropy oxides.•Obtaining homogenous powders with high thermal stability up to 1100 ​°C.•Improving the Ms of the high entropy oxide up to 14.6 emu/g by controlling the thermal regime.•Enhancing the SBET value up to 121 ​m2/g by changing the fuels.