Demagnetizing curves

Figure 9 shows typical demagnetization curves for the materials of Table 8 (104,105). A material group may include more than one grade. In that case the values for the two extreme iC-values are given. 

Fig. 9. Demagnetization curves for M-ferrites at high K values (see Table 8).

Fig. 10. Demagnetization curves of hard magnetic materials A, Nd2Fe B B, Sm(Co, Cu,Fe,Zr)2 C, SmCo D, bonded SmCo E, Alnico 5 F, Mn—Al—C G, Alnico 8 H, Cr—Co—Fe I, ferrite , bonded ferrite. To convert T to G, multiply by 10". ...

The effect of heat treating in a magnetic field on the demagnetization curves for Alnico V. 

Fig. 9.34 Demagnetization curves for an oriented barium hexaferrite (curve A) and an isotropic hexaferrite (curve B).

Sm2Fei7Nx powders are produced commercially since 1999 by the reduction and diffusion process [136]. The currently mass-produced powder has a BHimx of 290 kJ/m3 with /ioMt = 1.35 T and fi(iHc = 1.1 T. Milling and surface treatment have been optimized to improve the squareness of the demagnetization curve and resistance to corrosion [137]. 

Fig. 3.35. Room-temperature demagnetization curves of resin-bonded Sm20Fe70Ti10 and Sm26Fe64Ti10 samples prepared by mechanical alloying...

Fig. 22. Demagnetization curves of sintered MM, xSmj(Co5 magnets with different samarium contents.

Fig. 30. Demagnetization curves of sintered SmCo5 magnets cooled from the annealing temperature at different rates. (After Paladino et al. 1975.)...

Fig. 37. Comparison of the second-quadrant demagnetization curves of commercially produced bonded REPM and older types of matrix magnets.

The temperature coefficient of MHC was obtained from measurements of demagnetization curves at several temperatures, each traced after fully remagnetizing the sample at room temperature. As an example, fig. 39 shows such a set of curves for a sintered SmCo5 magnet of average production quality. The coefficient of Br is taken from the reversible remanence versus temperature curve traced after a first heating cycle to 100 °C, i.e., the so-called irreversible loss has been eliminated. Both... 

Fig. 38. Comparison of REPM with older permanent magnets. B versus H demagnetization curves typical of high-grade commercial magnets of the types indicated.

Fig. 39. Demagnetization curves of a sintered SmCo5 production magnet measured at four temperatures. (After Mildrum et al. 1981.) Note The scale markers on top indicate the end points of permeance lines that may be drawn from the origin. Their intercepts with the B versus H-curve define operating points with the indicated unit permeance values, p = — Bd/Hd = 1,..., 10.

Figure 15.11 Demagnetization curves for oriented (top) and isotropic or random (bottom) hexagonal ferrites." ...

Fig. 13. Demagnetization curve of a Nd-Fe-B sintered magnet with (BFf)max = 444 kJ/m in the 2nd quadrant...

Typical technical alloys and their properties are listed in Table 4.3-41. Characteristic demagnetization curves are shown in Fig. 4.3-63. 

Tables 4.3-48 and 4.3-50 list the magnetic properties of typical Coi7Sm2 based magnets andtheirphysical properties, respectively. Figures 4.3-69a-c show characteristic demagnetization curves.

Table 4.3-55 shows the basic magnetic properties of hard magnetic ferrites. The properties of actual products are shown in Fig. 4.3-77. The demagnetization curves of type YBM-9B, which have the best magnetic properties, are shown in Fig. 4.3-78. 

The demagnetizing curves for NdjjFe Bg as well as for Ndj3 gDy, 5Fey7Bg magnets are plotted in fig. 23 (Sagawa et al. 1984b). The coercive field increases... 

Fig. 26. Demagnetizing curves for Nd-Fe-B magnets after thermal demagnetizing (----------) and the...

In case of Nd-Fe-B magnets heated at 300°C for 3 h in argon atmosphere, irreversible losses are small ( 0.5%) (Narasimhan 1985a). The changes in demagnetizing curves by heating the samples are shown in fig. 29. By heating at 150°C, the coercive force diminished considerably. 

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