The Effect of Niobium and Boron Content on Magnetic Properties and Corrosion Resistance of Pr-Fe-Co-B-Nb HD Magnets

2008 ◽  
Vol 591-593 ◽  
pp. 96-101
Author(s):  
J.D. Angelo ◽  
C.C. Motta ◽  
Luzinete Pereira Barbosa ◽  
Hidetoshi Takiishi ◽  
Isolda Costa ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Boron Content ◽  
Permanent Magnets ◽  
Magnetic Behavior ◽  
Optimum Amount ◽  
Sintered Magnets

The hydrogenation decrepitation process was employed to produce sintered magnets using a mixture of two alloys. The effect of niobium and boron content on the magnetic properties of Pr14FebalCo16BxNby-type sintered magnets was studied. Niobium and boron have a significant effect on the magnetic behavior of these permanent magnets. The optimum amount of boron was 6 at% and niobium should be kept below to 0.50 at%. The squareness factor (0.90) has been improved considerably and good overall magnetic properties (Br=1320 mT, iHc=700 kAm-1 and (BH)max=315 kJm-3) have been achieved for the sintered magnets prepared from the Pr14Fe63.85Co16B6Nb0.15 alloy.

Improved corrosion resistance and magnetic properties of Nd‐Fe‐B‐type sintered magnets with Mo and Co

1991 ◽  
Vol 69 (8) ◽  
pp. 5844-5846 ◽  
Author(s):  
Satoshi Hirosawa ◽  
Shuji Mino ◽  
Hiroyuki Tomizawa
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Sintered Magnets

Modification of the magnetic properties and corrosion resistance of Nd-Fe-B permanent magnets with addition of cobalt

1991 ◽  
Vol 175 (2) ◽  
pp. 185-198 ◽  
Author(s):  
S Szymura ◽  
H Bala ◽  
G Pawłowska ◽  
Yu.M Rabinovich ◽  
V.V Sergeev ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Permanent Magnets

Electroless Ni-Co-P Coatings on Sintered Nd-Fe-B Magnets with Improved Corrosion Resistance

2009 ◽  
Vol 75 ◽  
pp. 53-56 ◽  
Author(s):  
Tian Yu Ma ◽  
Hua Gen Ying ◽  
Mi Yan
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Permanent Magnets ◽  
Corrosion Current ◽  
Operating Conditions ◽  
Slight Reduction ◽  
Bath Composition ◽  
Nacl Solution ◽  
Electroless Ni

Electroless Ni-Co-P coatings have been deposited on sintered Nd-Fe-B permanent magnets by optimizing the bath composition and operating conditions. The corrosion resistance of coated Nd-Fe-B magnets was significantly improved and corresponding corrosion current density Icorr in 3.5 wt. % NaCl solution decreased by two orders of magnitude. Coated with 12μm-thick Ni-Co-P, Nd-Fe-B magnets possessed slight reduction in magnetic properties, with a modest loss of remanence (Br) by 3.9 % and coercivity (iHC) by 4.5 %.

Effect of boron content on magnetic properties and microstructure of PrFeCoBNb HDDR permanent magnets

2005 ◽  
Vol 285 (1-2) ◽  
pp. 290-295 ◽  
Author(s):  
L.P. Barbosa ◽  
H. Takiishi ◽  
L.F.C.P. Lima ◽  
R.N. Faria
Keyword(s):  
Magnetic Properties ◽  
Boron Content ◽  
Permanent Magnets

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.

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