Elinvar Characteristics of Amorphous Alloys and Their Applications

The elastic properties and the Elinvar characteristics of various kinds of amorphous alloys are introduced. The Elinvar characteristics of Fe-base ferromagnetic amorphous alloys arises from their large ΔE effect. The elastic properties are sensitively affected by the internal stress, and the Elinvar characteristics is also obtained even in nonferromagnetic amorphous alloys such as Pd-Si and Ni-Si-B alloy systems by annealing or cold-rolling. A large stiffening is observed in Fe-base amorphous alloys in the saturated magnetic field, being different from the pole effect. The applications of the amorphous Elinvar alloys to mechanical vibrators and delay lines are described as examples, and then the merits and problems for their applications are pointed out from the practical point of view

On the Magnetization Process in an Iron-Phosphorus-Carbon Amorphous Ferromagnet

The B-H hysteresis loop and the magnetic domain structure have been examined for an amorphous Fe_P_C_7 ribbon alloy produced by the centrifugal solidification technique. The as-quenched alloy exhibits soft-ferromagnetic properties which are characterized by a rectangular type loop with the large Barkhausen jumps and low coercive force of about 0.12 Oe. Magnetic domain structure consists of the 180°-domain and the maze-domain. By annealing for 350 mins at 300℃, the coercive force decreases to 0.06 Oe. An additional annealing increases again the coercive force by transformation of the amorphous to the b. c. c. crystalline phase

Soft Magnetic Co-Ti-B Amorphous Alloys with High Corrosion Resistance

Co-Ti-B ternary amorphous ribbons were prepared by the melt-quenching method, and their soft magnetic properties, hardness and corrosion resistance have been investigated. With increasing titanium content, the Curie temperature decreases monotonically, while the crystallization temperature gradually increases. These alloys are magnetically very soft, that is, the coercive force takes a minimum value of 0.01 Oe and the maximum permeability shows a large value of 6×10^4 around x=0.05 for (Co_Ti_x)_B_ amorphous alloys. Their linear magnetostrictions are also quite small, being of the order of about -2.5×10^. In addition, these amorphous alloys have a high hardness and an excellent corrosion resistance. Therefore. Co-Ti-B amorphous alloys are promised as the soft magnetic materials for electromagnetic devices

Compositional Effect on Crystallization of (Fe, Ni, Co)-Si-B Amorphous Alloys

Compositional effect on the structural changes during heating up to 700℃ has been examined with a number of amorphous alloys of X-Si-B and (X, Y)_Si_B_ (X, Y : Fe, Ni, Co) by differential scanning calorie and Vickers hardness measurements, transmission electron microscopy and X-ray diffraction analysis. (1) The amorphous phase of X-Si-B alloys is obtained in the compositional range of 20 to 30 at% metalloid contents. The crystallization temperature of these amorphous alloys is low at low metalloid contents, but it increases with increasing metalloid content. The crystallization process changes in the vicinity of 27～29 at% metalloid contents. Below and above this metalloid content, the amorphous alloys crystallize following the process of Am→Am+MS-I→MS-I +MS-II→Stable. In the lower metalloid contents the MS-I phase is a crystal with the same structure as each mother metal, while in the higher contents it is a compound containing a large amount of metalloid elements. At the intermediate metalloid content (27～29 at%), these MS-I phases do not precipitate, but MS-II phase appears directly from the amorphous matrix and transforms finally to stable phases. (2) The crystallization process of amorphous (X, Y)_Si_B_ alloys proceeds through two metastable phases (MS-I and MS-II) and finally to stable phases. The crystalline structure of MS-I phase agrees well with that of equilibrium phase at room temperature for the X-Y binary alloys

High Permeability Properties of Amorphous Co-Fe Base Alloys

Amorphous alloys of (Fe_Co_x)_P_C_7 and (Fe_Co_x)_Si_B_ were prepared by rapid quenching from the melt by using two solidification techniques of centrifugal and roller types. Specimens were ribbons in form. Measurements were made of B-H hysteresis loop, effective permeability at high frequencies, longitudinal magnetostriction, electrical resistance, Vickers hardness and tensile strength. The magnetostriction is zero at a composition near x=0.94, being positive in the range of 0x>0.94. The alloy of Fe_Co_Si_B_ having a nearly zero magnetostriction exhibits the best soft magnetic properties ; the coercive force is 0.006 Oe and the maximum permeability is about 820×10^3 after annealing at 150℃ in a magnetic field. In addition, this alloy has a high effective permeability at higher frequencies up to about 100 kHz, high hardness and high tensile strength

New Co-Fe Amorphous Alloys as Soft Magnetic Materials

Amorphous alloys of (Fe_Co_x)_P_C_7 and (Fe_Co_x)_Si_B_ Were prepared by quenching from the melt by using the centrifugal type and roller type solidification techniques. Specimens were all ribbons in form. Measurements were made of B-H hysteresis loops, effective permeabilities at high frequencies, longitudinal magnetostrictions, electrical resistances, specific gravities and Vickers hardnesses. These alloys are magnetically very soft. The magnetostriction is zero at a composition near x=0.94, being positive in the range of 0≤x0.94. The coercive force and the permeability depends on the absolute value of magnetostriction. The alloy (x=0.94) having a vanishingly small magnetostriction exhibits the best soft magnetic properties : the coercive force is 0.006 Oe, the maximum permeability is 7.0×10^5 and the effective permeability is about 7×10^3 at higher frequencies up to about 100 KHz. In addition to these, this alloy has a high Vickers hardness of 910. Possible applications of this alloy are discussed

Pharmacokinetic Study on Excretion of Inorganic Fluoride Ion, a Metabolite of Sevoflurane

Blood and urinary inorganic fluoride ion concentration was determined in six healthy volunteers after inhalation of 2% sevoflurane for one hour. The serum inorganic fluoride ion concentration increased 30 min after discontinuation of inhalation to 14.8 ± 3.0 μmol/liter, which was about 10 times higher than the level before inhalation. The serum elimination constant of inorganic fluoride was calculated to be 0.000467 and the half-life was 1,487 min. The urinary excretion rate of inorganic fluoride ion was the highest ( 452 nmol/min) after 12-24 hr. The urinary excretion rate constant of inorganic fluoride was calculated to be 0.000268 and the half-life was 2,583 min. The distribution volume of inorganic fluoride excreted in the urine was calculated to be 127 liters. This value showed that fluoride ion produced in the cell cannot readily pass through the cell membrane due to its polarity, resulting in a delay of the maximum excretion rate of inorganic fluoride until the first or second day after inhalation of the anesthetic.This study was supported in part by a Grant-in-aid for Science Research from the Ministry of Education, Science and Culture of Japan and a Grant-in-aid from the Association for the Advancement of Medicine of the Tsuchiya Foundation

The Pole Effect of Ferromagnetic Thin Sheets and Stiffening of Fe-B Base Amorphous Alloys

Several kinds of ferromagnetic crystalline thin sheets have been made by cold rolling, and some ferromagnetic amorphous ribbons have been prepared from the melts by rapidly quenching method. At the fundamental mode, the so-called "pole effect" of thin sheets has become more pronounced with increasing magnetic field, but this effect has almost vanished below about 100 of the length to thickness ratio of the specimens even at the fundamental mode. The "pole effect" of thin sheets and amorphous ribbons has decreased with increasing the frequency of mode, becoming nearly zero at the third tone mode or more. Magnetic field dependence of Young\u27s modulus for amorphous alloys has been almost saturated above 100 Oe at the third tone mode, and the temperature dependence of Young\u27s modulus for Fe_B_ amorphous alloy has showed a stiffening below the Curie temperature. This behavior is very similar to the "pole effect", but the former is not related to the latter because the "pole effect" has been almost reduced by measuring at the third tone mode. Such a peculiar phenomenon has not been observed in Co-B amorphous alloys

Magneto-resistance Effect and Electric Resistance of Single Crystals of Cobalt

The preparation of long bar specimens of single crystals of close-packed hexagonal cobalt, about 10 cm long, was succeeded for the first time by the present authors, and with these crystals, the anisotropy of electrical resistivity and the magneto-resistance effect were measured up to the field of 1000 Oe. It was found that the specific electrical resistivity was largest in the direction of c-axis and smallest in the direction perpendicular to the axis, being 10.280×10^Ω-cm and 5.544×10^Ω-cm, respectively, and the values of ΔR/R were about 0.4 per cent and about 0.2 per cent the respective directions

Young\u27s Modulus and Delay Time Characteristics of Ferromagnetic Fe-Si-B Amorphous Alloys

The temperature dependence of thermal expansion and Young\u27s modulus of amorphous Fe-Si-B alloys prepared by the roller quenching technique was measured in order to examine their delay time characteristics. The thermal expansion coefficient of as-prepared alloys was in the order of 7～9×10^/℃ depending on the content of metalloids. The temperature coefficient of Young\u27s modulus varied from 0 to -40×10^/℃ with ordinary annealing and magnetic annealing, and the Elinvar characteristics caused by a large ΔE effect was obtained for several alloys. The temperature coefficient of the delay time calculated from thermal expansion and Young\u27s modulus was nearly zero for several alloys. Therefore, these amorphous alloys are expected to be useful for ultrasonic delay lines