On the Demagnetizing Factor of Cylindrical Rods

The ballistic demagnetizing factor of cylindrical rods of ferromagnetic substances, whose dimension ratio is smaller than 10, was experimentally determined by a new method using the demagnetizing curve of New K. S. Magnet alloy having a high coercive force. The relationship between the demagnetizing factor, N, and the dimension ratio_l m, was expressed as follows : N=55(m-0.54)^, m<10

Magnetic Properties of Spheroidal Graphite Cast Iron

The magnetic properties of spheroidal and flake graphite cast irons of similar composition cast into sand moulds of various diameters were measured, and the results obtained were as follows : Under the same degree of graphitization, the maximum induction, the coercive force and the hysteresis loss of spheroidal graphite cast iron were lower than those of flake graphite cast iron, and so the maximum permeability and the residual induction were higher. With increasing degree of graphitization, the maximum permeability increased, whereas the other four quantities decreased

Variation of Internal Friction with Magnetization in Nickel

The internal friction Q^ of nickel annealed at 1000℃ for 10hr was measured in a magnetic field by the electrostatic driving method. The results obtained are as follows : (1) With decreasing magnetic field H from a magnetically saturated state, Q^ increases from about H=30 Oe and shows a maximum at H=15 Oe. (2) The magnetic hysteresis loss Q^_h was separated from the whole Q^ through measurement of the dynamic stress with an interference comparameter. (3) When Q^_h is expressed as a function of magentization I/I_s, Q^_h shows a maximum at I/I_s=0.6 ; it becomes smaller with increasing driving frequency f and vanishes at f=5.8 kHz

The Wiedemann Effect of the Magnetostriction Alloy "Alfer" at High Temperatures

The Wiedemann effect of "Alfer" (12.91 per cent Al-Fe alloy) was measured with the annealed specimen at high temperatures. As the temperature rises, the effect gradually decreases at the constant current through the specimen, and also the higher the temperature is, the weaker the field is for the maximum effect. When the current through the specimen as well as the longitudinal field is constant, the effect gradually decreases with the rise of temperature, and bcecomes extremely small at the magnetic transformation point of the Fe_3Al superlattice, and vanishes at the magnetic transformation point of α phase. The effect of Ni and Fe was measured to compare with that of Alfer. The temperature dependence of the effect of Ni is similar to that of Alfer, but that of Fe is different from both, that is, it gradually increases as the temperature rises, and after reaching a maximum at about 600℃, rapidly decreases, becoming zero at the magnetic transformation point

On the Magnetic Shunt Characteristics of Fe-Ni-Cr Alloys and M. S. Alloy

For the purpose of improving the magnetic shunt alloys hitherto used, the magnetic properties of Fe-Ni-Cr alloys, containing 30～60% of Ni, 1～18% of Cr and having no allotropic transformation, were measured at various temperatures ranging from -50° to 100° It has been found that those alloys with the magnetic transformation point of about 100° show excellent characteristics of magnetic shunt as follows : The permeability in 400 Oe at 0° are 5～20 and their temperature coefficient, 0.003～0.040, the permeability varying almost linearly with the temperature. And the authors have named them "M. S Alloy"

On the Magnetostriction of Iron-Aluminium Alloys and a New Alloy "Alfer"

The magnetostriction of iron-aluminium alloys has been measured by the apparatus designed by the present investigators in various longitudinal fields of less than 1200 Oersteds. The positive magnetostriction of iron gradually increases by the addition of aluminium, while the negative one descreases. All the alloys containing more than 5.90% Al have only a positive magnetostriction, and especially in the case of alloys containing more than 8.80% Al the magnetostriction always increases with the magnetizing field or the intensity of magnetization ; showing no maximum. The magnetostriction at a constant field of 1, 100 Oersteds shows a negative value, in the range of lees than 5.3% Al content, while a positive value in the aluminium content above this percentage. In the range of the aluminium content 11.5-13.2% the magnetostriction is very high ; its highest value being 40×10 of 13.14% Al allcy. These alloys may be excellent magnetostriction materials for a supersonic cscillator and have been called "Alfer" by the present investigators

Thermal Expansion Coefficient of Fe-Ni(fcc) Alloys

The thermal expansion coefficient, α, was measured over the range from 800℃ to room temperature for Fe-Ni(fcc) alloys. The results obtained are as follows : (1) On the temperature vs. α curve, a peak appears at the Curie temperature, T_c, in the composition range above 42% of Ni but none in the range of 42-30% of Ni. (2) T_c of the alloys with more than 42% of Ni is present in the γ phase at a temperature higher than the upper limit for (α+γ) mixture phase in the equilibrium diagram. (3) the value of α_P obtained from α by climinating the magnetic contribution shows a minimum in the Invar range as in the case of α. This may suggest that the interatomic cohesive force must be considered in addition to the magnetic effect in making clear the origin of Invar property

Magnetic Properties of Magnet Alloys of Iron, Wolfram and Molybdenum

The residual induction and the coercive force of alloys of iron, wolfram and molybdenum system were measured after various heat-treatments. The alloy containing 15 per cent of wolfram and 15 per cent of molybdenum showed the best characteristics when quenched at 1300℃ and then annealed at 660℃ for 3 hours, that is to say, the residual induction, the coercive force and the maximum energy product amounted respectively to 8600 gauss, 310 oersted and 835.000 gauss-oersted

On Young\u27s Modulus and Grain Size in Nickel-Copper Alloys

Young\u27s modulus and the grain size have been measured with 10 kinds of polycrystalline ferromagnetic nickel-copper alloys annealed at 700°, 800°, 900°, 1000°and 1100℃. The following empirical relation has been found between Young\u27s modulus E and the average area of crystal grains S : E = E_0 - B log S, where E_0 and B are constants. Young\u27s modulus vs. composition curves for alloys with the same grain size were not always similar to one another, but every curve showed a minimum. The composition corresponding to the minimum shifted toward the nickel side as the grain size became large. With the addition of copper, Young\u27s modulus of nickel with comparatively small grains increased, whereas that with comparatively large grains decreased. These results suggest that the complication of the so-far as observed Young\u27s modulus vs. composition curves for nickel-copper alloys may be due partly to the difference in the grain size of the individual specimens. Finally, the measured results were compared with those calculated by the formula derived by Voigt and Reuss