Magnetic Hardening Mechanism in Sintered R-Fe-B Permanent Magnets

1987 ◽  
Vol 96 ◽  
Author(s):  
M. Sagawa ◽  
S. Hirosawa
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
State Of The Art ◽  
Spontaneous Magnetization ◽  
Experimental Results ◽  
Surface Conditions ◽  
Hardening Mechanism ◽  
Sintered Magnets ◽  
Field Coefficient ◽  
Magnetic Hardening

ABSTRACTThe state-of-the-art description of the magnetic hardening mechanism in the sintered Nd-Fe-B permanent magnet is given. Recent experimental results concerning the coercivity-anisotropy (Hc -HA) correlation in B-rich Pr-Fe-B and Nd-Fe-B sintered magnets and the inhluence of the surface conditions of the sintered Nd-Fe-B magnets on the coercivity are reported. These results are interpreted in terms of the μ0Hc versus cμ0 HA -NIS plot, where I is the spontaneous magnetization of R2 Fe14 (R=Pr or Nd) and N the effective demagnetization field coefficient.

Magnetic hardening mechanism in sintered R–Fe–B permanent magnets

1988 ◽  
Vol 3 (1) ◽  
pp. 45-54 ◽  
Author(s):  
M. Sagawa ◽  
S. Hirosawa
Keyword(s):  
Temperature Dependence ◽  
Permanent Magnets ◽  
Spontaneous Magnetization ◽  
Short Review ◽  
Experimental Results ◽  
Surface Conditions ◽  
Hardening Mechanism ◽  
Intrinsic Coercivity ◽  
Field Coefficient ◽  
Magnetic Hardening

After a short review on temperature dependence of the intrinsic coercivity in sintered Nd–Fe–B-type magnets is given, recent experimental results concerning the coercivity-anisotropy (HC–HA) correlation in B-rich Pr–Fe–B and Nd–Fe–B sintered magnets and the influence of the surface conditions of the sintered Nd–Fe–B magnets on the coercivity are reported. The results are interpreted in terms of the μoHc vs cμoHA – NIs plot, where Is is the spontaneous magnetization of R2Fe14B (R = Pr or Nd) and N is the effective demagnetization field coefficient.

Study of the Spinning Mechanism Resulting from Permanent Magnet Linear Actuation

2012 ◽  
Vol 721 ◽  
pp. 255-260
Author(s):  
Koichi Oka ◽  
Feng Sun ◽  
Akira Tsurumi ◽  
Gota Nakamura
Keyword(s):  
Permanent Magnet ◽  
Remanent Magnetization ◽  
Permanent Magnets ◽  
Experimental Results ◽  
Strain Gauges ◽  
Measurement Device ◽  
Linear Movement ◽  
Integral Element ◽  
Method Analysis ◽  
Element Method

This paper describes an analysis of torque characteristics of a noncontact spinning system using linearly actuated magnets. This noncontact spinning system spins the suspended object (here is an iron ball) without contact by the remanent magnetization and the linear movement of four permanent magnets. In this paper, the remanent magnetization point is modeled, and the rotational torque of this mechanism is calculated by IEM (Integral Element Method) analysis. The rotational torque is also measured using a measurement device with strain gauges. According to the IEM analysis results and the experimental results, the rotational torque characteristics of the noncontact spinning system are discussed.

scholarly journals Comparative Review of Brushless PMAC and PMDC Motor Drives

2020 ◽  
Author(s):  
Rajesh Pindoriya
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
High Efficiency ◽  
State Of The Art ◽  
High Reliability ◽  
Motor Drives ◽  
Compact Size ◽  
Comparative Review ◽  
Depth Analysis ◽  
Alternative Current

<div>This paper presents a state of the art on brushless </div><div>Permanent Magnet Alternative Current (PMAC) and </div><div>Permanent Magnet Direct Current (PMDC) motor drives. The </div><div>brushless PMAC and PMDC motor drives are the latest choices </div><div>of researchers due to their high efficiency, silent operation, </div><div>compact size, high reliability, and low maintenance </div><div>requirements. These motors are preferred for numerous </div><div>applications. An in-depth analysis of PMAC and PMDC motor </div><div>drives have been discussed. The Permanent Magnets (PMs)</div><div>motor drives can be classified into two categories, first is PMAC </div><div>motor drives, i.e. PMSM and the second one is PMDC motor</div><div>drives, i.e. BLDC motors. There has been a long </div><div>misunderstanding between the two ways of driving and </div><div>controlling a motor with no windings on the rotor but only </div><div>PMs. In this paper given a comprehensive analysis of both </div><div>motor drives. So, beginner of the research scholars are easily </div><div>able to understand about brushless PMAC and PMDC motor </div><div>drives.</div>

Evolution of intrinsic coercivity in Pt-Co-B alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 202-203
Author(s):  
N. Qiu
Keyword(s):  
Permanent Magnets ◽  
Ternary Alloys ◽  
Good Thermal Stability ◽  
Hardening Mechanism ◽  
Potential Applications ◽  
Magnetic Hardening ◽  
Rapidly Solidification ◽  
Evolution Of Microstructure ◽  
Rapidly Solidified ◽  
Thermal Stability Of

New permanent magnets based on Pt-Co-B ternary alloys have been developed by rapidly solidification with subsequent heat treatments. The coercivity achieved in the Pt-Co-B ternary alloys is more than double the highest coercivity observed in the Pt-Co binary system. Good thermal stability of the coercivity produced by annealing provides a basis for consolidation processes such as hot isotropic pressing to produce bulk magnets from the rapidly solidified Pt-Co-B materials. Increased coercivity coupled with special properties such as high Curie temperature, corrosion resistance and ductility may expand the potential applications for these alloys. The evolution of microstructure and its effect on coercivity from annealing the as-quenched materials are investigated to understand the magnetic hardening mechanism and optimize the magnetic properties.

A Low Frequency Permanent Magnet Passive Vibration Isolator

2012 ◽  
Vol 586 ◽  
pp. 328-336
Author(s):  
Qiang Li ◽  
Deng Feng Xu ◽  
Jin Chun Hu ◽  
Liu Hao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Load Capacity ◽  
Semiconductor Industry ◽  
Low Frequency ◽  
Magnetic Suspension ◽  
Experimental Results ◽  
Vibration Isolator ◽  
Rubber Membrane ◽  
Guide Device

Magnetic suspension vibration isolators have attracted significant attention in the field of semiconductor industry and high precision equipments. However, it is impossible to levitate an object by only permanent magnet due to instability of permanent magnets. It needs a guide device or active control to hold the magnetic suspension passive vibration isolator (MSPVI) at equilibrium position. In order to overcome the instability of the permanent magnets, the linear bearing, rubber O-ring and rubber membrane are applied in the MSPVI. The transmissibility of the MSPVI was calculated and subsequently measured. The experimental results show that the MSPVI can achieve low natural frequency with the help of the rubber membrane which is superior to the linear bearing and o-ring. Beside, the vibration isolating performance of the MSPVI is measured. The experimental results reveal that the MSPVI achieves the lowest resonant frequency when the load capacity of the MSPVI reaches maximum value.

scholarly journals Static Characterization of the Driving, Normal and Stall Forces of a Double-Sided Moving-Permanent Magnet-Type Planar Actuator Based on Orthogonal Planar Windings

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3526
Author(s):  
Marilia A. da Silveira ◽  
Marcos J. Susin ◽  
Aly F. Flores Filho ◽  
David G. Dorrell
Keyword(s):  
Permanent Magnet ◽  
External Force ◽  
Analytical Methods ◽  
Permanent Magnets ◽  
Magnetic Coupling ◽  
Experimental Results ◽  
Average Sensitivity ◽  
Stall Force ◽  
Numerical And Analytical Methods

This work presents a study of the traction, normal and stall forces in a two-sided planar actuator with orthogonal planar windings and a mover that comprises two cars magnetically coupled to each other through two pairs of permanent magnets (PMs). There is no ferromagnetic armature core because of the permanent magnets array in the mover and orthogonal traction forces can be generated in order to move both cars jointly in any direction on a plane. The stall force is the minimal force necessary to break up the magnetic coupling between the two cars. When one of the cars is subjected to an external force through the x- or y-axis, the cars can become out of alignment with respect to each other and the planar actuator cannot work properly. The behavior of the forces was modelled by numerical and analytical methods and experimental results were obtained from tests carried out on a prototype. The average sensitivity of the measured static propulsion planar force along either axis is 4.48 N/A. With a 20-mm displacement between the cars along the direction of the x-axis and no armature current, a magnetic stall force of 17.26 N is produced through the same axis in order to restore the alignment of the two cars

scholarly journals Direct reuse strategies of rare earth permanent magnets for PM electrical machines – an overview study

2019 ◽  
Vol 86 (2) ◽  
pp. 20901
Author(s):  
Ziwei Li ◽  
Afef Kedous-Lebouc ◽  
Jean-Marc Dubus ◽  
Lauric Garbuio ◽  
Sophie Personnaz
Keyword(s):  
Rare Earth ◽  
Permanent Magnet ◽  
End Of Life ◽  
Permanent Magnets ◽  
State Of The Art ◽  
The State ◽  
Electrical Machines ◽  
Heavy Rare Earth

The global supply of heavy rare earth magnets can become risky with the soaring demand of rare earth permanent magnet (PM) machines. One of the promising solutions is to reuse or recycle permanent magnets from end-of-Life electrical machines. This paper is an overview study of the state-of-the-art permanent magnet reuse and recycling research for electrical machines. Some methodologies for quantifying the recyclability of permanent magnet of electrical machines are also introduced.

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