Effect of the strong magnetic field on the magnetic interaction between two non-magnetic particles migrating in a conductive fluid

2009 ◽  
Vol 85 (1) ◽  
pp. 14002 ◽  
Author(s):  
Z. Sun ◽  
T. Kokalj ◽  
M. Guo ◽  
F. Verhaeghe ◽  
O. Van der Biest ◽  
...  
Author(s):  
I. Zolotarevskii

Purpose of work. To ascertain the causes of the abnormally large displacement of the martensitic point in steels and iron alloys in strong pulsed magnetic fields at low temperatures. Research methods. Generalization of experimental and theoretical investigations of the strong magnetic field influence on the martensitic transformation in steels and iron alloys, taking into account the magnetic state of austenite. The obtained results. The distributions of the martensitic point displacement ΔMS from the content of the main component - iron and the temperature of the martensitic γ → α- transformation beginning (martensitic point MS) in different experiments are obtained. It is shown that the obtained temperature dependence ΔMS(MS) in a strong magnetic field at low temperatures decomposes into two components, one of which correlates with the generalized Clapeyron-Clausius equations, and the other is opposite to it. In addition, it was found that steels and alloys with intense γ → α- transformation in a magnetic field contain at least 72.5% iron (wt), which at low temperatures in the fcc structure is antiferromagnetic. Scientific novelty. The anomalous temperature dependence of the distribution ΔMS(MS) in a strong magnetic field is explained on the basis of quantum representations of the magnetic interaction of atoms in the Fe-Ni system. This effect is associated with a number of other invar effects, in particular, with an abnormally large spontaneous and forced magnetostriction, a strong dependence of the resulting exchange integral on the interatomic distance. The point of view according to which in these alloys in a magnetic field γ → α- transformation occurs by the type of “magnetic first kind phase transformation” is substantiated. It is assumed that the nucleation of the martensitic phase in a magnetic field occurs in (at) local regions of γ- phase with disoriented atomic magnetic moments (with high compression and increased forced magnetostriction). Practical value. The information obtained in this work provides grounds for explaining the kinetic features of the transformation of austenite into martensite in steels and iron alloys.


2006 ◽  
Vol 20 (24) ◽  
pp. 1543-1548 ◽  
Author(s):  
SHUXIN BAI ◽  
SHUN LI ◽  
HONG ZHANG ◽  
KE CHEN ◽  
HONGNIAN CAI

Hybrid-bonded isotropic Nd-Fe-B /anisotropic Sm 2 Co 17 magnets with different mass fraction of Sm 2 Co 17 powders had been analyzed with the aid of magnetization and demagnetization curves. It was found that the Henkel plot of magnet with 10 wt.% Sm 2 Co 17 lies above the Wohlfarth line at low magnetic field but goes down slowly and then lies below the Wohlfarth line at high magnetic field. This shows magnetizing interaction at first and demagnetizing interaction at last, and presents an s-shaped behavior that has been seen frequently in nanocomposite exchange-coupled magnets. The demagnetization curve of 10 wt.% Sm 2 Co 17 content hybrid-bonded magnet exhibits a magnetically single phase behavior which has also been seen frequently in nanocomposite exchange-coupled magnets, indicating complex magnetic interaction between these two magnetic particles. As a result, a small increase in remanence and energy product are observed in hybrid-bonded Nd-Fe-B/Sm 2 Co 17 magnets with 10% mass fraction of Sm 2 Co 17.


2010 ◽  
Vol 150-151 ◽  
pp. 1595-1598
Author(s):  
Xiao Ling Peng ◽  
Hai Biao Wei ◽  
Xiao Yang ◽  
Rui Ping Yue ◽  
Hong Liang Ge

Magnetic fluid is a stable colloidal dispersion of ferromagnetic particles in a liquid carrier. Once a magnetic field is applied to magnetic fluids (MF), various structures of MF are formed. A detailed understanding of structures and particle distributions in gradient magnetic fields is much important. But very few works have been done on this. In the present study, the effects of magnetic field gradient and magnetic interaction among magnetic particles on the structures of MF are investigated using a two-dimensional Monte Carlo simulation. The results show that a gradient distribution of magnetic particles is formed under gradient magnetic fields. However, as the interaction between magnetic particles increases, the distribution gradient decreases, accompanied by the formation of chain-like clusters. Moreover, with increasing the magnetic interaction, particle distribution changes from grass-like clusters to needle-like ones.


2011 ◽  
Vol 109 (8) ◽  
pp. 084917 ◽  
Author(s):  
Z. Sun ◽  
M. Guo ◽  
J. Vleugels ◽  
B. Blanpain ◽  
O. Van der Biest

2010 ◽  
Vol 23 ◽  
pp. 199-214 ◽  
Author(s):  
Zhi Sun ◽  
Muxing Guo ◽  
Jef Vleugels ◽  
Omer Van der Biest ◽  
Bart Blanpain

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.


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