Phase formation and composition of Mn–Zn ferrite powders prepared by hydrothermal method

Abstract

Mn–Zn ferrite powders were prepared by hydrothermally aging the coprecipitates of compositional metal ions using ammonium hydroxide as a precipitant. R value (alkalinity) = (moles of added OH−)/[(moles of added Zn2+) × 2 + (moles of added Mn2+) × 2 + (moles of added Fe3+) × 3] was introduced to adjust the amount of added ammonia. The results show that the R value of starting suspension and hydrothermal time have similar and dominant effects on the composition, spinel ratio, and crystallite size of synthesized powders. From the analyses of x-ray diffraction (XRD) and inductively-coupled plasma (ICP), it notes that no α–Fe2O3 peak in the XRD patterns of powders synthesized at R = 2–3, 150 °C × 2 h, may be due to lower degree of crystallinity and less amount of α–Fe2O3 existing in these powders. Both the increase of hydrothermal time and of R value can promote the crystallinity of powders and also cause a significant loss of zinc, hinting that in the hydrothermal process, the loss of zinc may play a crucial role in the crystallinity of hydrothermally synthesized powders.

Structure induced tunable magnetic properties of Zn substituted Mn1−xZnxFe2O4(x= 0–1) NPs

“…They possess cubic spinel structure with general formula AB 2 O 4 , where A and B refer to the tetrahedral and octahedral cation sites, respectively. Type of cations and their distribution between the two interstitial sites in the spinel unit cell determine their intrinsic magnetic properties [10, 11]. This cation distribution depends on the ionic radii of the cation [12].…”

Formation of crystalline MnFe2O4 powder by flame-combusting freeze-dried citrate precursors

“…To have a better-controlled microstructure, the ferrite powder used in production should have the characteristics of high chemical homogeneity, ultrafine particle sizes with narrow size distribution, spherical-like shapes, and high sinterability. Several nonconventional techniques, such as coprecipitation [1][2][3][4][5], spray pyrolysis [6][7][8][9], sol-gel processing [10], hydrothermal processing [11][12][13], precursor processing [14][15][16][17], freeze-drying [18,19], and combustion processes [20,21], are used or are under development to fulfill powder requirements.…”

Synthesis of manganese zinc ferrite using ferrous pickle liquor and pyrolusite ore

“…It is widely used in many electronic and magnetic applications such as inductors, AC/DC converters, wide-band transformers, ferrite antennas, noise filters, cores for electromagnetic interference (EMI) suppression, chokes for power supplies, inductor and transformer cores and in switch mode power supplies (SMPS), microwave applications in the Megahertz range, recording media of high density and low noise level, thermally sensitive magnetic fluids (Wolfarth 1986;Goldman 1999;Lin et al 1999;Rath et al 1999;Mandal et al 2001).…”