PROPERTIES AND APPLICATIONS OF HIGH ... - Vacuumschmelze

[5]. The irreversible polarization losses ∆Jirr due to the temperature dependence of the coercivity HcJ
and due to the thermal aftereffect can be recovered by remagnetization.
TC(B r ) =
TC(H cJ ) =
in %/K, T 0 < T < T 1
20°C 60°C 80°C
100°C
-20 -15 -10 -5 0
magnetic field strength H in kA/cm
120°C
Figure 3: Dependence of the demagnetization curves J(H) and B(H) of VACODYM ®*) 722 HR magnets on the
temperature. The typical magnetic properties amount to: Br = 1.47 T, HcJ = 9.5 kA/cm, (BH)max = 415 kJ/m³ at 20 °C.
rel. polarization losses dJ irr/J in %
0
-5
-10
-15
-20
-25
Nd 14.3DyFe 76.7B 8 magnets
Aging temperature: 130 °C
1 10 100 1000 10000
exposure time in h
B/µoH = -2.0
B/µoH = -1.1
B/µoH = -0.5
Fig. 4: Irreversible polarization losses of sintered Nd14.3DyFe76.7B8 magnets with different load lines B/µoH at a
temperature of 130 °C in dependence of the exposition time.
® registered trade mark of VACUUMSCHMELZE GmbH & Co. KG, *) licenser Sumitomo Special Metals Corp.
1,6
1,2
0,8
0,4
0,0
-0,4
-0,8
polarization J, induction B in T