scholarly journals Aluminum Substitutions in Nd-Fe-B Sintered Magnets

1987 ◽  
Vol 96 ◽  
Author(s):  
J. K. Chen ◽  
G. Thomas
Keyword(s):  
Magnetic Properties ◽  
Grain Boundaries ◽  
Permanent Magnets ◽  
Rich Phase ◽  
Sintered Magnets ◽  
Sintered Permanent Magnets

ABSTRACTA microstructural and microanalytical study of aluminum substituted Nd-Fe-B sintered permanent magnets were carried out to determine the effect, if any, of aluminum on structure, composition, and magnetic properties, particularly on the observed increase in coercivity. It was found that Al enrichment occurred in the Nd-rich phase at the grain boundaries. The possible role(s) of this enrichment on the observed coercivity increase are discussed.

INFLUENCE OF Bi-ADDITIONS ON THE MAGNETIC AND MICROSTRUCTURAL PROPERTIES OF (Nd, Dy)-Fe-Al-B MAGNETS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 725-728
Author(s):  
P. SCHREY ◽  
M. VELICESCU
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Temperature Stability ◽  
Microstructural Properties ◽  
Magnetic Insulation ◽  
Intergranular Phase ◽  
Rich Phase ◽  
Sintered Magnets ◽  
Free Material

Powder metallurgical additions of Bi enhance the temperature stability of (Nd, Dy)-Fe-B permanent magnets. Bi is not solved in the hardmagnetic RE2Fe14B phase, thus does not influence the intrinsic magnetic properties, Only the microstructure of the sintered magnets is changed. Addition of a few wt.% of Bi leads to the formation of a new ternary intergranular phase with the composition Nd6Fe13Bi. This phase substitutes partially the intergranular Nd-rich phase providing the magnetic insulation of hardmagnetic grains. An enhancement of HCJ by about 40% was reached at 150 ºC for a Nd15.5Dy1.5Fe74AlB8 magnet containing 2.5 wt.% Bi compared to the Bi-free material.

The mechanism of enhanced magnetic properties of sintered permanent magnets by substitution of Pr for Nd

2012 ◽  
Vol 516 ◽  
pp. 73-77 ◽  
Author(s):  
Bicheng Chen ◽  
Xingmin Liu ◽  
Renjie Chen ◽  
Shuai Guo ◽  
Don lee ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Sintered Permanent Magnets

Magnetic properties of sintered permanent magnets R-Fe-Cu-B (R=Prand Nd)

1990 ◽  
Author(s):  
C.H. Lin ◽  
Y.M. Jean ◽  
C.J. Chen ◽  
T.Y. Liu ◽  
H.C. Kung ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Sintered Permanent Magnets

Preparation and Magnetic Properties of the Exchange Coupling NdFeB Nanocomposited Permanent Magnets

2007 ◽  
Author(s):  
Zongjun Tian ◽  
Shangdong Li ◽  
Youwei Du ◽  
Yinhui Huang
Keyword(s):  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Grain Boundaries ◽  
Exchange Coupling ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Energy Product ◽  
Remanence Ratio ◽  
Optimum Energy ◽  
Hard Magnetic Properties

The effect of indium additions on the microstructures and magnetic properties of Nd9Fe85−xB6Inx (x = 0–2) nanocomposites prepared by melt spinning was investigated. It was found that a certain amount of indium added to Nd9Fe85B6 magnets enhances the hard magnetic properties. The coercivity and remanence ratio of the magnet with 0.5 at.% indium increases from 405kA/m (no indium) to 465kA/m and from 0.7 to 0.86 respectively. Squareness of its hysteresis loop is also improved greatly. The optimum energy product (BH)max increases remarkably from 95kJ/m3 to 145kJ/m3. The origin for those enhancements is mainly attributed to the magnetically softened grain boundaries and enhanced crystallographical coherency by indium addition. The magnetic annealing is found to be helpful to enhance the coherency and coupling between hard and soft phases.

PrFeB Based Alloys Obtained by Melt Spinning for the Production of Permanent Magnets

2020 ◽  
Vol 1012 ◽  
pp. 314-318
Author(s):  
Marco Antonio Meira ◽  
Lucas Costa Moisés ◽  
Melissa Rohrig Martins da Silva ◽  
Susilene Real Janasi ◽  
Hidetoshi Takiishi
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Powder Metallurgy ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Wheel Speed ◽  
Essential Components ◽  
Intrinsic Coercivity ◽  
Sintered Permanent Magnets ◽  
Ejection Pressure

Rare earth permanent magnets are essential components in many fields of technology due to their excellent magnetic properties. There are some techniques used in the manufacture of permanent rare earth magnets: the powder metallurgy to obtain anisotropic HD sintered permanent magnets and the melt spinning and HDDR processes to obtain isotropic and anisotropic bonded permanent magnets. In this work, the influence of the melt spinning parameters on the microstructural and magnetic properties of the Pr14FebalCo16B6 alloy was studied. The alloy was melted and rapidly cooled at 9.9 x 105°C/s. The parameters used in the process were: wheel speed of 15 m/s and 20 m/s and ejection pressure of 25.3 kPa and 50.7 kPa. Ribbons and/or flakes of 30 μm thickness and width until 5 mm were obtained. Results show that the melt spinning alloys are nanocrystalline and that the parameters of the process influence the microstructure and their magnetic properties. Mean crystallite size up to 38.5 nm and intrinsic coercivity (iHc) up to 254 kA/m were obtained.

scholarly journals Structure and Properties of Nd-Fe-B Alloy Subjected to HDDR Process

2016 ◽  
Vol 61 (1) ◽  
pp. 217-220 ◽  
Author(s):  
M. Szymański ◽  
B. Michalski ◽  
M. Leonowicz ◽  
Z. Miazga
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Phase Transformation ◽  
Grain Boundaries ◽  
Master Alloy ◽  
Structure And Properties ◽  
Rich Phase ◽  
Average Grain Size ◽  
Reversal Phase ◽  
Neodymium Magnets

In this paper the Hydrogenation, Disproportionation, Desorption and Recombination (HDDR) route was tested, for the Nd-Fe-B master alloy, as a prospective procedure for recycling of sintered scrap neodymium magnets. The HDDR method is based on the hydrogen induced reversal phase transformation of Nd-Fe-B alloy: Nd2Fe14B + (2±x) H2 = 2NdH2±x + Fe2B + 12Fe. Microstructural observations (SEM), phase constitution studies (XRD) and measurement of magnetic properties (VSM) were done to investigate the HDDR transformation progress. It was observed that disproportionation reaction starts at the grain boundaries, where the Nd-rich phase is located. Average grain size was reduced and coercive material was produced as a result of the HDDR process. Obtained results are similar to literature data.

Magnetic properties on sintered permanent magnets R-Fe-Cu-B (R=Pr, Nd)

1990 ◽  
Vol 26 (5) ◽  
pp. 2607-2609 ◽  
Author(s):  
C.H. Lin ◽  
C.J. Chen ◽  
C.D. Wu ◽  
W.C. Chang ◽  
S.K. Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Sintered Permanent Magnets
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