Magneto-active ferrite-based paint pigments

Munteanu, Lenka; Masař, Milan; Sedlačík, Michal; Kohl, Miroslav; Kalendová, Andréa

doi:10.1063/5.0159567

Cited by 1 publication

(6 citation statements)

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“…It reduces the average density of composite particles and thus prevents the sedimentation of the solid phase [ 33 , 34 ]. The systems incorporating nickel have been reported seldom [ 35 ]. It has been observed that the magnetorheological effect depended on the morphology [ 36 ] and particle size [ 37 ] of the dispersed phase.…”

Section: Resultsmentioning

confidence: 99%

“…The sample with 8 g nickel had approximately three times higher performance while, for both samples above 450 kA m −1 , the performance remained the same as the nickel particles were magnetically saturated. It is important to note that there was a nickel ferrite-based magnetorheological fluid with a similar carrier [ 35 ]. Present composite particles have nearly two times higher performance with only 9 wt% loading, while the compared system [ 35 ] used 60 wt% particles.…”

Section: Resultsmentioning

confidence: 99%

“…It is important to note that there was a nickel ferrite-based magnetorheological fluid with a similar carrier [ 35 ]. Present composite particles have nearly two times higher performance with only 9 wt% loading, while the compared system [ 35 ] used 60 wt% particles.…”

Section: Resultsmentioning

confidence: 99%

“…The hybrid organic/inorganic composites displaying electrical conductivity and magnetic properties, polypyrrole-coated nickel microparticles, have been prepared and characterised. While the oxidation of pyrrole with iron(III) chloride in the presence of nickel does not provide desired composites due to the metal dissolution, the use of am- The magnetorheological performance as a function of the magnetic field for composites prepared with 8 g (squares) or 2 g nickel (circles) and the comparison with data reported in the literature [35] (triangles).…”

Section: Discussionmentioning

confidence: 99%

“…Present composite particles have nearly two times higher performance with only 9 wt% loading, while the compared system [35] used 60 wt% particles. The magnetorheological performance as a function of the magnetic field for composites prepared with 8 g (squares) or 2 g nickel (circles) and the comparison with data reported in the literature [35] (triangles).…”

Section: Magnetic Propertiesmentioning

confidence: 96%

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Conducting and Magnetic Hybrid Polypyrrole/Nickel Composites and Their Application in Magnetorheology

Jurča,

Vilčáková,

Kazantseva

et al. 2023

Materials

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Hybrid organic/inorganic conducting and magnetic composites of core–shell type have been prepared by in-situ coating of nickel microparticles with polypyrrole. Three series of syntheses have been made. In the first, pyrrole was oxidised with ammonium peroxydisulfate in water in the presence of various amounts of nickel and the composites contained up to 83 wt% of this metal. The second series used 0.1 M sulfuric acid as a reaction medium. Finally, the composites with polypyrrole nanotubes were prepared in water in the presence of structure-guiding methyl orange dye. The nanotubes have always been accompanied by the globular morphology. FTIR and Raman spectroscopies confirmed the formation of polypyrrole. The resistivity of composite powders of the order of tens to hundreds Ω cm was monitored as a function of pressure up to 10 MPa. The resistivity of composites slightly increased with increasing content of nickel. This apparent paradox is explained by the coating of nickel particles with polypyrrole, which prevents their contact and subsequent generation of metallic conducting pathways. Electrical properties were practically independent of the way of composite preparation or nickel content and were controlled by the polypyrrole phase. On the contrary, magnetic properties were determined exclusively by nickel content. The composites were used as a solid phase to prepare a magnetorheological fluid. The test showed better performance when compared with a different nickel system reported earlier.

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