Loading Effect of Sol-Gel Derived Barium Hexaferrite on Magnetic Polymer Composites

Abstract

Solution–processing methods were investigated as viable alternatives to produce the polymer-bonded barium hexaferrite (BaM). BaM powders were first synthesized by using the sol-gel auto-combustion method. While the ignition period in two synthesis batches varied, the morphology of hexagonal microplates and nanorods, as well as magnetic properties, were reproduced. To prepare magnetic polymer composites, these BaM powders were then incorporated into the acrylonitrile-butadiene-styrene (ABS) matrix with a weight ratio of 80:20, 70:30, and 60:40 by using the solution casting method. Magnetizations were linearly decreased with a reduction in ferrite loading. Compared to the BaM loose powders and pressed pellet, both remanent and saturation magnetizations were lower and gave rise to comparable values of the squareness. The squareness around 0.5 of BaM samples and their composites revealed the isotropic alignment. Interestingly, the coercivity was significantly increased from 1727–1776 Oe in loose BaM powders to 1874–2052 Oe for the BaM-ABS composites. These composites have potential to be implemented in the additive manufacturing of rare-earth-free magnets.

Magnetic Properties and Morphology Copper-Substituted Barium Hexaferrites from Sol-Gel Auto-Combustion Synthesis

“…Properties of barium hexaferrites at high frequencies were implemented in microwave absorbers [ 2 , 3 ]. Their incorporations into polymer composites were investigated to improve forming and mechanical properties [ 4 , 5 ]. There is growing interest in hard/soft magnetic composites with tunable properties, including the combination of barium hexaferrites with magnesium ferrites [ 6 ].…”

Magnetic, gas sensing properties, and structural parameters of barium–calcium hexaferrite synthesized by sol‐gel auto combustion method

“…[4] Barium ferrites play an important role in such applications as high-density recording media, ferro-fluids, catalysts, microwave devices, and gas sensors. There are various methods for the synthesis of hexaferrites including hydrothermal, [16] co-precipitation, [17] molten salt, [18] sol-gel, [19][20][21][22][23] selfcombustion sol-gel, [24][25][26][27] and solid-state reaction processes. [11,15,28] Among these, the self-combustion sol-gel method has the advantages of the product with high purity, small particle size, and high homogeneity, as well as the ability to control the chemical and phase composition.…”

“…However, limited studies have been performed on the substitution of barium cation in barium hexaferrite with calcium and its effect on changes in magnetic and especially in gas sensing properties. [19,23,24] The aim of this study is to investigate the effect of Ca 2+ cation substitution in different ratios (0 ≤ x ≤ 1) in barium-calcium hexaferrite Ba 1Àx Ca x Fe 12 O 19 structure by self-combustion sol-gel method on phase composition, microstructure, magnetic properties, and gas sensing properties.…”

Special Issue “Wet Chemical Synthesis of Functional Nanomaterials”

“…This Special Issue aimed to provide a forum to present some of the latest results in the area of synthesis, characterization and application of functional nanomaterials which are synthesized using wet chemical methods. With five articles and one review covering polymer oxide composites for magnetic applications [1], TiO 2 /Au nanostructured films for hydrogen sensors [2], mixed oxide nanoparticles derived from sacrificial metal organic frameworks [3], highly doped metal oxide colloidal nanocrystals for plasmonics [4], sol-gel derived mixed alkali niobate coatings for piezoelectric micro-devices [5], and solution-processed thin films transistors based on oxide heterojunctions [6], this special issue is a perfect representation of the breadth and impact of this dynamic, multidisciplinary, and impactful research field.…”

“…The ability to use earth-abundant elements coupled with simple and straightforward fabrication methods will constitute a major progress in this field. Sirisathitkul and co-workers developed magnetic composites based on barium hexaferrite magnetic particles dispersed within a polymeric matrix, and produced a composite material with the potential to be fabricated via 3D printing, owing to the mechanical properties achieved by the combination of inorganic fillers and an organic matrix [1]. High coercivity values of over 2000 Oe were demonstrated, proving the high performance of such composites, leading the way for further studies into the additive manufacturing of such composites.…”