Permeability, magnetic alloys

Permalloy Ni3Fe high permeability magnetic alloy Bozorth (1951)... 

Properties of Magnetic Alloys High-Permeability Magnetic Alloys ... 

Permeability, magnetic alloys, 12-105 to 113 Permeability of vacuum, 1-1 to 11 Permittivity (dielectric constant)... 

Figure 4-227. Magnetic flux-lines representation in a highly permeable iron alloy core.

Soft magnetic materials are characterized hy high permeability and low cnercivily. There are six principal groups of commercially important soft magnetic materials iron and low carbon sieels, iron-silicon alloys, iron-aluminum and iron-aluminuni-silicon alloys, nickel-iron alloys, iron-coball alloys, and ferrites. In addition, iron-boron-hased amorphous soft magnetic alloys are commercially available. Table I summarizes tile properties of some of these materials. Table 2 summarizes properties of some ferrites. Properties of amorphous soft magnetic alloys arc listed in Table 3. 

Mumetal /myoo-met-al/ [Trademark) A magnetic alloy containing about 75% nickel, the remainder being iron, copper, and chromium and sometimes molybdenum. It is easily magnetized and demagnetized, has a high permeability, and is used in transformer cores and electromechanical equipment. 

Masumoto, T., Watanabe, K., Mitera, M. Ohnuma, S. (1977). High magnetic permeability amorphous alloys of the FeNiSiB system. In Amorphous Magnetism II. Eds. R. A. Levy and R. Hasegawa, Plenum Press, New York, pp. 369-77. 

Permanent magnet alloys, which can be either Fe- or Co-based sintered materials containing rare earth elements and, optionally, Al, Ti, and other metals, are supplied with a-BN for increased coercive force [78 to 87]. a-BN is also added to ferrite materials consisting of FOgOg, MnO, ZnO, and NiO for increased magnetic permeability [88]. 

In the (FejCoi c) 8oB 20 system the saturation magnetostriction A.S passes through zero. Along with a proper selection of alloy composition this behavior gives rise to a particularly low coercivity, the highest permeability of all amorphous magnetic alloys, low stress sensitivity, and extremely low total losses. 

Fig. A.3-23 Average grain size, coercivity and initial permeability of a nanocrystalline soft magnetic alloy as a function of the annealing temperature [3.23]...

A survey of the field dependence of the amplitude permeability of various crystalline, amorphous, and nanocrystalline soft magnetic alloys is given in Fig.4.3-31 [3.12]. Figure 4.3-32 [3.23] represents the frequency behavior of the permeability jx of different soft magnetic materials for coirparison. 

Fig. 4.3-31 Amplitude permeability-field strength curves of soft magnetic alloys (/ = 50 Hz) amorphous (a) nanocrystaUine in) [3.12]...

A separate study was the improvement of magnetic permeability in soft alloys such as are used in transformers and motors by lining up the orientations of individual crystal grains, also known as a preferred orientation this became an important subspeciality in the design of transformer laminations made of dilute Fe-Si alloys, introduced more than 100 years ago and still widely used. 

Several of the low-temperature superconducting metals, such as lead, brass, and some solders (particularly lead-tin alloys), experience property changes when they become superconducting. Such changes can include specific heat, thermal conductivity, electrical resistance, magnetic permeability, and thermoelectric resistance. Consequently, the use of these superconducting metals in the construction of equipment for low-temperature operation must be evaluated carefully. 

It is worth mentioning here that a compound-free bcc-Fe nanostructure with grain sizes smaller than L0 can be obtained even in a binary Fe Zrg alloy [3, 60] although the initial permeability of nanocrystalline Fe92Zr8 (2 x 103 at 1 kHz) is similar to that of magnetically soft Fe-Si steels. Weak... 

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