scholarly journals Dependence of the Hydrogen Pressure on the Magnetic Properties of NdFeB Anisotropic Magnet Powders Produced by the HDDR Method.

2000 ◽  
Vol 24 (4−2) ◽  
pp. 407-410 ◽  
Author(s):  
C. Mishima ◽  
N. Hamada ◽  
H. Mitarai ◽  
Y. Honkura
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Pressure ◽  
Anisotropic Magnet

Effects of reduced hydrogen pressure on magnetic properties of HDDR-treated NdFeGaB alloy powders

1998 ◽  
Vol 267 (1-2) ◽  
pp. 270-273 ◽  
Author(s):  
Jian-rong Gao ◽  
Xiao-ping Song ◽  
Xiao-tian Wang
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Pressure

Suitable Hydrogen Pressure Induced Anisotropy in HDDR-Treated Pr-Fe-B Powders

2012 ◽  
Vol 625 ◽  
pp. 328-331
Author(s):  
Guang Bing Han ◽  
Shuang Fu ◽  
Min Liu ◽  
Ru Wei Gao
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Pressure ◽  
Induced Anisotropy ◽  
Crystal Texture

Anisotropic Pr12.5Fe72.5Co6Cr2B7 magnetic powders are obtained by varying the desorption H2-pressure of the hydrogenation disproportionation desorption recombination (HDDR) process. The magnetic powders with a desorption H2-pressure of 30 kPa have the magnetic properties of Br =0.96 T, iHc=8.2 kOe and Br/Bs =0.78, whereas the magnetic powders obtained with a higher and a lower desorption H2-pressure are isotropic. A distinct lamella crystal is observed in the 30 kPa desorption H2-pressure products and may be related to the anisotropy in the HDDR-treated powders. It is believed that the desorption H2-pressure has great effect on the formation of crystal texture in the HDDR Pr-Fe-B powders.

scholarly journals Effect of processing hydrogen pressure on magnetic properties of HDDR Nd-Fe-B magnet

2020 ◽  
pp. 1-1
Author(s):  
X.B. Liu ◽  
M.S. Kesler ◽  
M.F. Besser ◽  
M.J. Kramer ◽  
M.A. McGuire ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Pressure

Low Hydrogen Pressure Induced High Anisotropy in HDDR-Treated Nd13Fe75Co4B8 Powders

2012 ◽  
Vol 602-604 ◽  
pp. 161-164
Author(s):  
Guang Bing Han ◽  
Shuang Fu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnetic Properties ◽  
Hydrogen Pressure ◽  
Crystal Texture ◽  
High Anisotropy ◽  
Lamella Structure ◽  
Scanning Electron

High anisotropic Nd13Fe75Co4B8 magnetic powders are obtained with low desorption H2-pressure of the hydrogenation disproportionation desorption recombination (HDDR) process. Scanning electron microscopy (SEM) indicates a lamella structure in the 20 kPa desorption H2-pressure HDDR products and may be related to the high anisotropy. The magnetic powders with a desorption H2-pressure of 20 kPa have the magnetic properties of Br =0.86 T and Mr/Ms =0.81.This shows that the H2-pressure has great effect on the formation of crystal texture in the HDDR Nd-Fe-B powders.

Texture Development in Nd-Fe-V and Nd-Fe-B Alloys by Hot Forging in View of Improving Permanent Magnet Properties

2005 ◽  
Vol 105 ◽  
pp. 291-296
Author(s):  
Sophie Rivoirard ◽  
I. Popa ◽  
Daniel Chateigner ◽  
B. Ouladdiaf ◽  
Patricia de Rango ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Neutron Diffraction ◽  
High Speed ◽  
Magnetic Phase ◽  
Hot Forging ◽  
Forging Process ◽  
Cast Alloys ◽  
Hot Forging Process ◽  
Anisotropic Magnet

A high speed hot forging process was applied to Nd-Fe-B and Nd-Fe-V as cast alloys in order to develop both the microstructure and the crystallographic texture appropriate for permanent anisotropic magnet properties. Neutron diffraction texture analyses are used to demonstrate the effect of the hot forging process on both kind of alloys. Microstructural changes are an important feature on forging in both cases. Coercivity is developed in the Nd-Fe-B alloy mainly from grain size reduction and disappearance of free iron. Stabilisation of the Nd(Fe,V)12 hard magnetic phase is achieved from the iron and Nd-rich microstructure of the starting Nd-Fe-V material. A comparison of the crystallographic textures of Nd2Fe14B and Nd(Fe,V)12 phases is done to account for the development of extrinsic magnetic anisotropy. In both cases, a nearly fibre texture is obtained in correlation with the symmetry of the deformation. However, the orientations are quite different in both alloys and the consequences on the magnetic properties are evidenced.

Effect of Desorption Hydrogen Pressure on Anisotropy of HDDR-Treated Nd-Fe-B Powders

2011 ◽  
Vol 284-286 ◽  
pp. 1525-1528
Author(s):  
Guang Bing Han ◽  
Shuang Fu ◽  
Min Liu ◽  
Hao Su ◽  
Ru Wei Gao
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Pressure ◽  
Crystal Texture

Anisotropic Nd13.5Fe79.5B7 magnetic powders are obtained by varying the desorption H2-pressure of the hydrogenation disproportionation desorption recombination (HDDR) process. The magnetic powders with a desorption H2-pressure of 10 kPa have the magnetic properties of Br =0.61 T and Mr/Ms =0.67, whereas the magnetic powders obtained with a higher and a lower desorption H2-pressure are isotropic. A lamella crystal is observed in the 10 kPa desorption H2-pressure products and may be related to the anisotropy in the HDDR-treated powders. It suggests that the desorption H2-pressure has great effect on the formation of crystal texture in the HDDR Nd-Fe-B powders.

Hydrogen Absorption and Magnetic Properties of HO2Fe14BHx Hydrides

2012 ◽  
Vol 190 ◽  
pp. 163-166 ◽  
Author(s):  
R. Damianova ◽  
S.A. Nikitin ◽  
R. Bezdushnyi ◽  
I.S. Tereshina ◽  
E.A. Tereshina ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Intermetallic Compound ◽  
Temperature Variation ◽  
Hydrogen Concentration ◽  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
Constant Pressure ◽  
Spin Reorientation ◽  
Continuous Control ◽  
Spin Reorientation Transition

Magnetic properties of the hydrides of an intermetallic compound Ho2Fe14B are studied in the temperature range 78 700 K. The temperature dependencies of magnetization σ (Т) are obtained under continuous control of the hydrogen content in the samples investigated. The dependence of the Curie (TC) and the spin-reorientation transition (TSR) temperatures on hydrogen pressure (P) and its concentration (x) are determined. The dependence of hydrogen concentration on pressure at constant temperatures (isotherms x (P)) in the vicinity of TC and the temperature variation of hydrogen concentration at a constant pressure (isobars x (T)) are investigated.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Microstructure in soft magnetic E3 (S1, Al) (Sendust) alloys

1988 ◽  
Vol 46 ◽  
pp. 770-771
Author(s):  
June D. Kim
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Ternary Phase Diagram ◽  
Vertical Tube ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Soft Magnetic ◽  
Quenching Temperature ◽  
Thin Foils ◽  
Vertical Tube Furnace

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.

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