γ-Radiation induced sedimentation of magnetic particles in magnetic fluids

Kopčanský, P.; Černák, Jozef; Tima, T.; Zentko, A.; Τimko, M.; Slanco, P.

doi:10.1016/0304-8853(90)90030-t

Cited by 5 publications

(9 citation statements)

References 6 publications

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“…The two irradiated states and the performance of the present FF seals can be compared directly with the results of [7]. Further evidence of the irradiation effect on ferrofluids was offered in [12] where magnetization of kerosene-based ferrofluid containing Fe 3 O 4 has been studied. Influence on agglomeration and sedimentation in the ferrofluid was observed with doses up to only 4.5 Gy.…”

Section: De-magnetization Of Permanent Magnets -Radiation Effects On Annular Permanent Magnets (Nd 2 Fe 14 B and Sm 2 Co 27 )mentioning

confidence: 90%

“…Several radiation damage studies with thermal neutrons and γ-ray exposure have been performed with FF seals and respective material components to determine their threshold radiation dose limit [4,[6][7][8][9][10][11][12]. In spite of these studies the effects of radiation on the chemical and physical properties of ferrofluids are still not yet well understood.…”

Section: Introductionmentioning

confidence: 99%

“…Changes in the viscosity, surface tension and colloid stability of ester-based ferrofluid (manufactured by Rigaku Co.) were studied [7] following irradiation using a γ-ray source for up to 1.8 MGy dose and these were found to be negligible. Kopčanský and co-workers [12] also studied the effect of γ-radiation on the magnetization of kerosene-based ferrofluid and observed that (a) the saturation magnetization and number of magnetic particles both decrease with increased γ-irradiation dose and (b) γradiation induces agglomeration and sedimentation with increased dose. It was assessed [12] that radiation induces breakdown of long molecular chains in the carrier fluid resulting in the acceleration of agglomeration and subsequently sedimentation.…”

Section: Introductionmentioning

confidence: 99%

“…Kopčanský and co-workers [12] also studied the effect of γ-radiation on the magnetization of kerosene-based ferrofluid and observed that (a) the saturation magnetization and number of magnetic particles both decrease with increased γ-irradiation dose and (b) γradiation induces agglomeration and sedimentation with increased dose. It was assessed [12] that radiation induces breakdown of long molecular chains in the carrier fluid resulting in the acceleration of agglomeration and subsequently sedimentation. Nanoscale gadolinium oxide (Gd 2 O 3 ) based ferrofluids coated with synthesized surfactant were γ-ray irradiated to doses in the range of 32 Gy-2.635 kGy [13], and with the help of high-resolution transmission electron microscope (HRTEM) it was determined that the particles developed intergranular defects.…”

Section: Introductionmentioning

confidence: 99%

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Performance degradation of ferrofluidic feedthroughs in a mixed irradiation field

Simos

Fernandes

Mittig

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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Ferrofluidic feedthrough (FF) rotary seals containing either NdFeB or SmCo-type permanent magnets have been considered for use in the target and beam dump systems of the Facility for Rare Isotope Beams (FRIB). To evaluate their performance under irradiation three FF seals were irradiated in a mixed field consisting of fast neutrons, protons and γ-rays to an average absorbed dose of 0.2, 2.0, and 20.0 MGy at the Brookhaven Linac Isotope Producer facility (BLIP). The radiation types and energy profiles mimic those expected at the FRIB facility. Degradation of the operational performance of these devices due to irradiation is expected to be the result of the de-magnetization of the permanent magnets contained within the seal and the changes in the ferrofluid properties. Post-irradiation performance was evaluated by determining the ferrofluidic seal vacuum tightness and torque under static and dynamic conditions. The study revealed that the ferrofluidic feedthrough seal irradiated to a dose of 0.2 MGy maintained its vacuum tightness under both static and rotational condition while the one irradiated to a dose of 2.0 MGy exhibited signs of ferrofluid damage but no overall performance loss. At 20 MGy dose the effects of irradiation on the ferrofluid properties (viscosity and particle agglomeration) were shown to be severe. Furthermore, limited de-magnetization of the annular shaped Nd 2 Fe 14 B and Sm 2 Co 27 magnets located within the irradiated FFs was observed for doses of 0.2 MGy and 20 MGy respectively.

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Section: De-magnetization Of Permanent Magnets -Radiation Effects On Annular Permanent Magnets (Nd 2 Fe 14 B and Sm 2 Co 27 )mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Performance degradation of ferrofluidic feedthroughs in a mixed irradiation field

Simos

Fernandes

Mittig

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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“…From the point of basic and applied research it will be very interesting to study physical properties of magnetic uids after electron radiation. Up to now there is very poor information about inuence of radiation on the physical properties of magnetic uids [5]. Magnetic hyperthermia is one of the widely studied application of magnetic uids in medicine [69].…”

mentioning

confidence: 99%

Magnetic Properties of Biocompatible Magnetic Fluid after Electron Irradiation

et al. 2012

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The magnetic particles in the water-based magnetic uids were sterically stabilized by natrium oleate to prevent their agglomeration and consequently the adsorption of poly-ethylene-glycol (PEG) was carried out to improve the biocompatibility of the magnetic particles. Two sets of samples were prepared. The rst set of the samples was with dierent molar weight of PEG (Mw = 400, 1000, 10 000 and 20 000) at the constant weight ratio of PEG/Fe3O4 = 0.25 and the second one was with dierent weight ratio of PEG/Fe3O4 and constant molar weight of PEG (Mw = 1000). The samples were irradiated with 20 Gy. The same reduction of saturated magnetization (about 10%) after electron irradiation with 20 Gy was observed for all prepared samples.

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