engleski

Phase development during the high-energy ball-milling of zinc oxide and iron - The mechanism of zinc ferrite formation

High-energy ball-milling of the powder mixtures of zinc oxide and iron at different weight ratios was performed in air using the planetary ball mill with a stainless steel milling assembly. The milling time varied from 1 to 30 hours. For thermal stability study, the final milling products (30 hours) were subjected to temperature treatment at 500 °C and 1000 °C. Structural and microstructural changes during the ball-milling were monitored using X-ray powder diffraction (XRD), Mössbauer spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive Xray spectrometry (EDS). The combined results of quantitative crystal phase analysis and Mössbauer spectroscopy indicated that the formation of zinc ferrite goes through a gradual oxidation and incorporation of iron ions into the zincite (ZnO) lattice. Iron oxidation goes in two steps, first from Fe^0 to Fe^2+ (appearance of the wüstite-type phase) and finally to Fe^3+ ions (formation of the zinc ferrite phase).

ZnO; Fe; Zinc ferrite; High-energy ball-miling; FE-SEM; EDS; XRD; Mossbauer spectroscopy

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