Evolution of phosphate coatings during high-temperature annealing and its influence on the Fe and FeSiAl soft magnetic composites

Huang, Maoqin; Jiang, Yinzhu; Yan, Mi

doi:10.1016/j.jallcom.2015.04.201

Cited by 120 publications

(16 citation statements)

References 40 publications

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“…The increase of permeability is beneficial for decreasing hysteresis loss of composites, although deformed glass flakes between FeSi spheres can block DC current between different spheres, but it is connected when AC current at high frequency. The increased effective permeability may give rise to increased eddy current [14,15].…”

Section: Resultsmentioning

confidence: 99%

Effect of magnetic properties in FeSi soft magnetic composites by low melting glass powder as adhesive and insulating agent

Zhu

Feng

et al. 2021

J Mater Sci: Mater Electron

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FeSi/1wt% glass soft magnetic composites are prepared by mechanically mixing, compacting, and annealing, their morphology is examined by SEM, and their magnetic properties are measured by MPMS and B-H analyzer. The morphology of SEM shows that when the annealing temperature is higher than the melting point of the glass, the glass particles between the FeSi balls are deformed into flakes. The sample has higher saturation magnetization and lower power loss. The magnetic permeability and mechanical strength of the sample increase with the increase of annealing temperature, but the best power loss characteristics emerge at annealing temperature of 400 °C.

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Section: Resultsmentioning

confidence: 99%

Effect of magnetic properties in FeSi soft magnetic composites by low melting glass powder as adhesive and insulating agent

Zhu

Feng

et al. 2021

J Mater Sci: Mater Electron

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“…Only the diffraction peak intensity of the α-Fe phases of the hybrid-coated powders via the ball-milling method decreases slightly and no other diffraction peaks could be observed. This could be explained primarily by the possibility that the content of the phosphate layer is too small to be detected, or that the phosphate layer is amorphous [18]. Previous research has reported that amorphous Al2O3 would transfer to δ-Al2O3, θ-Al2O3 and α-Al2O3 at 750 °C, 1000 °C, 1100 °C, respectively [21].…”

Section: Smcs With Hybrid Phosphate-alumina Coatingmentioning

confidence: 99%

“…However, a previous paper [17] has reported that the phosphate coatings would crystalize or decompose at a relatively high temperature (above 500 • C), dramatically decreasing the electric resistivity. Huang et al [18] investigated the effect of annealing temperatures on the composition and the magnetic properties of the phosphate-coated SMCs; their results showed that phosphate coatings degrade into iron phosphide after annealing at 600 • C, and the magnetic properties worsened as a result. Owing to the high bond energy of the Al-O covalent bond, Al 2 O 3 possess high electrical resistivity and high temperature resistance.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Phosphate-Alumina Iron-Based Core-Shell Soft Magnetic Composites Fabricated by Sol-Gel Method and Ball Milling Method

Pan

Qian

Wang

et al. 2020

Metals

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Novel Fe-based soft magnetic composites (SMCs) with hybrid phosphate-alumina layers were prepared by both sol-gel and ball-milling methods. The effects of the fabrication methods and the addition of Al 2 O 3 particles on the microstructure and the soft magnetic performance of SMCs were studied. The formation of the hybrid phosphate-Al 2 O 3 shell not only leads to the decrease of the total core loss, but also results in the reduction of the permeability and saturation magnetization. However, the degree of decrease caused by the different methods were not identical. The sample with 8% Al 2 O 3 prepared by the sol-gel method showed the best magnetic performance, exhibiting a high-amplitude permeability (µ a ) of 85.14 and a low total core loss (Ps) of 202.3 W/kg at 50 mT and 100 kHz. The hysteresis loss factor and the eddy current loss factor were obtained by loss separation. The results showed that the samples with the same Al 2 O 3 content prepared by different methods exhibited almost the same total core loss. However, the contribution of the hysteresis loss and the eddy current loss showed an obvious difference in behavior because of the change of the particle shapes and the refinement of the particle size during the ball-milling process.

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“…Then, the introduction of inorganic substances improves the heat resistance of the insulating layer, such as SiO 2 , Al 2 O 3 , MgO, Fe 3 O 4 , phosphate coating [3,[10][11][12][13] etc. Among these coatings, phosphate coating has been widely used in the fabrication of the SMCs due to its simple preparation process, high electrical resistivity and strong adhesion to the powder surfaces [14]. However, high temperature can destroy the phosphate coating, which reduces the resistivity and increases the loss.…”

Section: Introductionmentioning

confidence: 99%

Improved magnetic properties of iron-based soft magnetic composites with a double phosphate-SiO2 shells structure

Yuan

Sun

Tian

et al. 2021

J Mater Sci: Mater Electron

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Herein a double shells structure was proposed to overcome the drawbacks such as poor heat resistance, incomplete insulation and high core loss coating of ironbased soft magnetic composites (SMCs) with single shell structure. The surface of the iron powder was coated with a double shells structure composed of an inner phosphate coating and an outer SiO 2 coating through phosphating and hydrolysis successively. Subsequently, the effects of different SiO 2 addition amount on the microstructure of iron powder and magnetic properties of SMCs were studied. The introduction of SiO 2 in the double shells structure inhibited the decomposition and failure of phosphating layer after being annealed at a high temperature. The iron powder coated with the phosphate-SiO 2 insulating layer was still effective after annealing in a N 2 atmosphere at 570 °C, achieving the purpose of eliminating residual stress and improving magnetic properties. The optimal process parameters were set at 0.2 wt% phosphoric acid and 0.5 wt% tetraethyl orthosilicate to fabricate the phosphate-SiO 2 double shells. The iron-based SMCs presented excellent magnetic properties with B s of 1.29 T and P s of 169.2 W/kg (measured at 1 T and 1 kHz). In addition, the core loss of SMCs introduced with SiO 2 is 83% lower than that of SMCs produced by the phosphating process. This paper provides a feasible method for improving the magnetic properties of SMCs.

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Evolution of phosphate coatings during high-temperature annealing and its influence on the Fe and FeSiAl soft magnetic composites

Cited by 120 publications

References 40 publications

Effect of magnetic properties in FeSi soft magnetic composites by low melting glass powder as adhesive and insulating agent

Effect of magnetic properties in FeSi soft magnetic composites by low melting glass powder as adhesive and insulating agent

Hybrid Phosphate-Alumina Iron-Based Core-Shell Soft Magnetic Composites Fabricated by Sol-Gel Method and Ball Milling Method

Improved magnetic properties of iron-based soft magnetic composites with a double phosphate-SiO2 shells structure

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