Effects of Co addition on the temperature dependence of the intrinsic coercivity in Pr‐Fe‐B sintered magnets

1988 ◽  
Vol 64 (10) ◽  
pp. 5553-5555 ◽  
Author(s):  
Satoshi Hirosawa ◽  
Masato Sagawa
Keyword(s):  
Temperature Dependence ◽  
Sintered Magnets ◽  
Intrinsic Coercivity ◽  
Co Addition

Elevated Temperature Properties of Sintered Magnets of (Nd,Dy)-Fe-B Modified with Cobalt and Aluminum

1987 ◽  
Vol 96 ◽  
Author(s):  
Y. Xiao ◽  
H. F. Mildrum ◽  
K. J. Strnat ◽  
A. E. Ray
Keyword(s):  
Elevated Temperature ◽  
Side Effects ◽  
Curie Temperature ◽  
Temperature Dependence ◽  
Open Circuit ◽  
Sintered Magnets ◽  
Temperature Coefficients ◽  
Energy Product ◽  
Intrinsic Coercivity ◽  
Curie Temperatures

ABSTRACTThe effect of small aluminum additions on the temperature dependence of remanence and intrinsic coercivity in Co- and Dy-containing Nd-Fe-B was studied. Sintered magnets were prepared and demagnetization curves measured at temperatures between −50 to +200°C. Curie temperatures and irreversible flux losses in open circuit were determined. Al increases the coercivity while decreasing remanence, energy product and Curie temperature. Other unfavorable side effects are the increase in temperature coefficients of Br and, especially, MHc. Substitution of Al is not beneficial for magnets used at elevated temperature.

MICROSTRUCTURE AND TEMPERATURE STABILITY OF SINTERED Nd-Dy-Fe-Co-Mo-Al-B MAGNETS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 721-724
Author(s):  
W. RODEWALD ◽  
P. SCHREY ◽  
B. WALL
Keyword(s):  
Solid Solution ◽  
Surface Treatment ◽  
Corrosion Behaviour ◽  
Temperature Stability ◽  
Partial Replacement ◽  
Compound A ◽  
Corrosion Tests ◽  
Sintered Magnets ◽  
Load Line ◽  
Intrinsic Coercivity

Simultaneous additions of Co and Mo or V, respectively, to Nd-Dy-Fe-Al-B alloys improve the temperature stability of sintered magnets. The intrinsic coercivity at 150 ºC amounts to 9 kA/cm for magnets with a Dy-content of 3 at.%. Hence magnets with a load line, B/μoH=−2, may be operated at temperatures up to 200 ºC. The additions of Mo or of V result in the precipitation of a tetragonal Mo2FeB2 compound, a=0.58 nm, c=0.32 nm, or of a tetragonal V3–xFexB2 compound, x=0.2...1.2, within the (Nd, Dy)2(Fe, Co, A1)14B grains. The dimensions of the precipitates range from 10 to 600 nm. Besides Mo2FeB2- or V3–xFex+B2-grains, respectively, with dimensions up to 10 μm were observed within the Nd-rich constituents. The intrinsic coercivity, however, is determined by nucleation of reversed domains. The addition of Co results in a partial replacement of the Nd-Fe solid solution by the Nd3Co compound. Corrosion tests revealed, that the corrosion behaviour is not improved significantly and depends much more on the surface treatment.

Abnormal temperature dependence of intrinsic coercivity in Sm(Co, Fe, Cu, Zr)z powder materials

1998 ◽  
Vol 73 (20) ◽  
pp. 3007-3009 ◽  
Author(s):  
J. F. Liu ◽  
T. Chui ◽  
D. Dimitrov ◽  
G. C. Hadjipanayis
Keyword(s):  
Temperature Dependence ◽  
Powder Materials ◽  
Intrinsic Coercivity ◽  
Abnormal Temperature

Coercivity temperature dependence of Sm2Co17-type sintered magnets with different cell and cell boundary microchemistry

2018 ◽  
Vol 452 ◽  
pp. 272-277 ◽  
Author(s):  
Nengjun Yu ◽  
Minggang Zhu ◽  
Liwei Song ◽  
Yikun Fang ◽  
KuiKui Song ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Cell Boundary ◽  
Sintered Magnets

The Effect of Cu, P, Ga and Gd on Microstructure and Magnetic Properties in the PrFeCoBNb HD Sintered Magnets

2010 ◽  
Vol 660-661 ◽  
pp. 273-278 ◽  
Author(s):  
T. Mendes ◽  
S.C. Silva ◽  
E.A. Périgo ◽  
Rubens Nunes de Faria Jr. ◽  
Hidetoshi Takiishi
Keyword(s):  
Magnetic Properties ◽  
High Energy ◽  
Alloying Elements ◽  
Phosphorus Addition ◽  
Sintered Magnets ◽  
Microstructural Parameters ◽  
Intrinsic Coercivity ◽  
Standard Composition ◽  
Curve Profile ◽  
Microstructure And Magnetic Properties

An evaluation of the effect of alloying elements on the microstructure and magnetic properties of Pr15FebalCo8B7Nb0.05Mx (M = Cu, P, Gd and Ga; 0 ≤ x ≤ 0.25) sintered magnets has been carried out. A mixture of alloys and the high-energy milling technique have been used to prepare the magnets. The alloying elements have influenced the remanence, intrinsic coercivity and particularly the squareness factor (SF). Phosphorus addition improved (BH)max (254 kJm-3 ) and SF around 10% (0.89). The same improvement addition on intrinsic coercivity was observed with Gallium (1100mT) compared to the standard composition Pr15FebalCo8B7Nb0.05 (1000mT) magnet. Comparisons between the squareness factors obtained using the J×μ0H curve profile (SF), the estimated (sf) using microstructural parameters and Sf using a (BH)max and Br correlation have also been carried out.

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.

The effect of Co addition on the fracture strength of NdFeB sintered magnets

2001 ◽  
Vol 9 (4) ◽  
pp. 269-272 ◽  
Author(s):  
Jianhua Jiang ◽  
Zhenpeng Zeng ◽  
Jian Yu ◽  
Jiansheng Wu ◽  
M. Tokunaga
Keyword(s):  
Fracture Strength ◽  
Sintered Magnets ◽  
Co Addition
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