Nano-micro composite magnetic fluids: Magnetic and magnetorheological evaluation for rotating seal and vibration damper applications
| Autor: | Ladislau Vekas, Florica Bălănean, Vlad Socoliuc, Daniela Susan-Resiga, Daniel Vizman, Oana Marinica |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Ferrofluid Materials science Demagnetizing field Analytical chemistry 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Magnetic field chemistry.chemical_compound Nuclear magnetic resonance Carbonyl iron chemistry 0103 physical sciences Volume fraction Magnetorheological fluid 0210 nano-technology Saturation (magnetic) Magnetite |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 406:134-143 |
| ISSN: | 0304-8853 |
| DOI: | 10.1016/j.jmmm.2015.12.095 |
| Popis: | In this paper, static magnetic properties and magnetorheological behavior of a set of 12 nano-micro composite magnetic fluids (CMFs) were studied. The samples with a ferromagnetic particle volume fraction ranging in a large interval φ F e = ( 1 ÷ 44 ) % were prepared by adding carbonyl iron powder in a highly concentrated transformer oil-based ferrofluid (FF). The ferrofluid has the magnetite volume fraction of φ F e 3 O 4 = 22.90 % and saturation magnetization of M s = 74 k A / m (930 Gs). No further additives were used in order to prevent sedimentation. It was noticed an increase of the static yield stress, of about 3 orders of magnitude, with the increase of the total solid volume fraction of samples and with the increase of the magnetic field, which varied between 0 kA/m and 950 kA/m. The dynamic yield stress (Herschel-Bulkley model) τ H B of the samples strongly increases with the magnetic field and shows a slight tendency of saturation for higher intensities of the magnetic field. There is a less pronounced increase of τ H B , about an order of magnitude with the increasing volume fraction of the iron particles. The relative viscosity increase induced by the magnetic field reaches a maximum for both considered shear rates: γ ⋅ = 7.85 s - 1 and γ ⋅ = 88.41 s - 1 and it was revealed an optimal volume fraction of Fe particles, φ F e = 20 % , corresponding to a total volume fraction of φ t o t ≈ 38 % , at which the magnetoviscous effect has its maximum value. The magnetic properties and also the magnetorheological and the magnetoviscous behavior of highly concentrated ferrofluid-based CMFs can be controlled by the addition of iron microparticles in order to attain the optimal concentration for the envisaged engineering applications, rotating seals and magnetorheological vibration dampers. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect