Iron-cobalt alloys

Of all known magnetic materials, Fe—Co alloys with about 35 wt% Co have the highest saturation polarization Is = 2.4 T at room temperature and the highest Curie temperature of nearly 950 °C. The intrinsic magnetic properties Is,Tc,Ki, and khki as a function of Co content are shown in Fig. 4.3-16. 

Since Ki and ks have minima at different Co contents, different compositions for different applications have been developed. A Fe-49 wt% Co-2 wt% V composition is commonly used. The V addition reduces the brittleness by retarding the structural ordering transformation, improves the rolling behavior, and increases the electrical resistivity. The workability of Co—Fe alloys is difficult altogether. Two further alloy variants containing 35 wt% Co and 27 wt% Co, respectively, are of technical interest. They are applied where highest flux density is required, e.g., in magnet yokes, pole 

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Soft magnetic materials are characterized by high permeabiUty and low coercivity. There are sis principal groups of commercially important soft magnetic materials iron and low carbon steels, iron—siUcon alloys, iron—aluminum and iron—aluminum—silicon alloys, nickel—iron alloys, iron-cobalt alloys, and ferrites. In addition, iron-boron-based amorphous soft magnetic alloys are commercially available. Some have properties similar to the best grades of the permalloys whereas others exhibit core losses substantially below those of the oriented siUcon steels. Table 1 summarizes the properties of some of these materials. 

Nickel-Iron-Cobalt Alloys for Sealing with Intermediate Glasses to... 

Iron citrate [2338-05-8] Iron-cobalt Iron-cobalt alloys... 

A few materials, termed ferromagnetic, attract a magnetic field very strongly and can themselves become magnetic, for example iron, cobalt alloys, magnetite. With these we are not further concerned here. 

Bae] Baer, G., Thomas, H., Properties and Strueture of the Iron-Cobalt Alloys with 50% Co and small Vanadium Content (in German), Z. Metallkd., 45(11), 651-655 (1954) (Electr. Prop., Experimental, Morphology, Phase Diagram, Phase Relations, 11)... 

Buckley, R.A., Microstructure and Kinetics of the Ordering Transformation in Iron-Cobalt Alloys, FeCo, FeCo-0.4%Cr, FeCo-2.5%V , Metal Sci., 9, 243-247 (1975) (Experimental, Kinetics, Morphology,, 8)... 

Alel] Alekseev, L.A., Dzhavadov, D.M., Tyapkin, Yu.D., Levi, R.B., Nature of the Effect of Cron the Stracture of Ordering Iron-Cobalt Alloys , Sov. Phys. Dokl., 22(6), 329-331 (1977), translated from Dokl. Akad. NaukSSSR., 234, 818 (1977) (Crys. Stracture, Experimental, 9) [1977Ale2] Alekseyev, L.A., Dzhavadov, D.M., Tyapkin, Yu.D., Levi, R.B., Influence of Chromium on the Stracture of Ordered Iron-Cobalt Alloys , Phys. Met. Metallogr., 44(4), 180-182 (1977), translated from Fiz. Metal. Metalloved., 44(4), 879-881 (1977) (Crys. Stracture, Experimental, 4)... 

Che2] Chen, C.W., Eleetronie Struetures of Manganese-Substituted Iron-Cobalt Alloys , Phys. 

As a way to stabilize metallic magnetic phases, metal alloys have been prepared. In particular, iron-cobalt alloys have attracted much attentiOTi due to their technological relevance to magnetic storage. In the bulk they are soft magnetic materials with saturation induction 15% larger than pure iron and with magnetizatiOTi values dependent on their composition. 

TABLE 9.12. Performance Characteristics of Iron/Cobalt Alloy Catalysts... 

T. Watanabe, Y. Suzuki, S. Tanii and H. Oikawa, The Effect of Magnetic Annealing on Recrystallization and Grain Boundary Character Distribution (GBCD) in Iron-Cobalt Alloy Polyciystals, Phil. Mag. Letters, 62,9-17 (1990). 

Smi] Smith, R.P., The Diffusivity of Carbon in y Iron-Cobalt Alloys , Trans. Metall. Soc. AIME, 230, 476-480 (1964) (Experimental, Kinetics, Thermodyn., 18)... 

Bur] Burylev, B.P., Determination of the Solubility Isotherms in the Ternary System Using Thermodynamic Properties of the Binary Alloys (in Russian), Izv. Vyss. Uchebn. Zaved., Khim., Khim. Tekhnol., 6, 910-914 (1965) (Phase Relations, Thermodyn., Calculation, 17) [1965Smi] Smith, R.P., The Activity of Carbon in Iron-Cobalt Alloys at 1000°C , Trans. Metall. Soc. 

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