The Effect of 'Hydrogenation – Recalcination' Cycling on the Magnetic Properties of Strontium Hexaferrite

Abstract

Strontium hexaferrite powder synthesized conventionally was treated in a hydrogen atmosphere and then recalcined in air. This process had a marked effect on the microstructure and on the magnetic properties of the initial sample. The process was repeated several times and the effects investigated. The results showed that the products of the treatment prior to recalcination are Fe and Sr7Fe10O22 and this resulted in a change in magnetic properties from hard to soft. Consequent calcination, resulted in the reformation of strontium hexaferrite but now with a much finer grain size. This resulted in a significant enhancement of the coercivity. The variation of the coercivity with the number of cycles indicated a maximum value of 413 kA/m which then remained constant with subsequent cycling.

Hydrothermal Synthesis of SrFe12O19 and Its Characterization

“…Mainly, other processes such as ball-milling [10], high temperature [11,12], coprecipitation or hydrothermal process [13][14][15] have been used to synthesize hexaferrite. Recently, Hessien et al [1] have synthesized the SrFe 12 O 19 nanoparticles from the natural product.…”

Preparation of strontium hexaferrite nano-crystalline powder by carbon monoxide heat treatment and re-calcination from conventionally synthesized powder

“…Gas heat treatment and re-calcination is a novel method which produce the hexaferrite nano-particles from conventionally synthesized powder. Hydrogen and nitrogen heat treatments and re-calcination have been investigated in the last decade [8][9][10][11]. In this work, the effects of carbon monoxide heat treatment and re-calcination on the microstructure and magnetic properties of conventionally synthesized strontium hexaferrite have been reported.…”

Optimization of hydrogen dynamic heat treatment and re-calcination for preparation of strontium hexaferrite nanocrystalline powder

“…Static gas heat treatment and re-calcination is a method which produces hexaferrite nanoparticles from conventionally synthesized powder and have been investigated in last decade [10][11][12][13]. Dynamic carbon monoxide heat treatment and re-calcination has also been reported recently [14].…”