Zinc ferrite

Zinc ferrites are a series of synthetic inorganic compounds of zinc and iron (ferrite) with the general formula of Zn_xFe_3−xO₄. Zinc ferrite compounds can be prepared by aging solutions of Zn(NO₃)₂, Fe(NO₃)₃, and triethanolamine in the presence and in the absence of hydrazine,^[1] or reacting iron oxides and zinc oxide at high temperature. Spinel (Zn, Fe) Fe₂O₄ appears as a tan-colored solid that is insoluble in water, acids, or diluted alkali.^[2] Because of their high opacity, zinc ferrites can be used as pigments, especially in applications requiring heat stability. For example, zinc ferrite prepared from yellow iron oxide can be used as a substitute for applications in temperatures above 350 °F (177 °C).^[3] When added to high corrosion-resistant coatings, the corrosion protection increases with an increase in the concentration of zinc ferrite.^[4]

One investigation shows that the zinc ferrite, which is paramagnetic in the bulk form, exhibits ferrimagnetism in nanocrystalline thin film format.^[5] A large room temperature magnetization and narrow ferromagnetic resonance line width have been achieved by controlling thin films growth conditions.^[6]

Moreover, a flexible electrode for hybrid capacitors was developed using nanostructured Gadolinium doped zinc ferrite (GZFO), reinforced with carbon nanotubes (CNT), and supported on aluminum foil (AF). The GZFO/C@AF electrode exhibited high capacitance, long cycle life, and excellent energy and power density, making it a promising choice for wearable electronic device power sources.^[7]

Recent advancements have explored the use of zinc ferrite in energy storage devices. Notably, a study published in RSC Advances in 2023 detailed the development of a flexible electrode for hybrid capacitors utilizing nanostructured gadolinium-doped zinc ferrite (GZFO). This material was reinforced with carbon nanotubes (CNTs) and supported on aluminum foil (AF), resulting in the GZFO/C@AF electrode. The electrode demonstrated a high specific capacitance of 887 F g⁻¹ at a current density of 1 A g⁻¹ and maintained 94.5% of its capacitance after 7000 charge–discharge cycles at 15 A g⁻¹. Additionally, it achieved an energy density of 40.025 Wh kg⁻¹ and a power density of 279.78 W kg⁻¹, indicating its potential for powering wearable electronic devices. ^[8]

See also

• Ferrite core
• Ferrite (magnet)
• Zinc smelting