JPH0693392A - Vitreous alloy having magneto-striction of almost zero for use in high frequency - Google Patents

Abstract

PURPOSE: To provide a glassy alloy which is especially suitable to use in high frequency application, whose magnetostriction is approximately zero, which is highly stable magnetically and thermally and has high magnetic permeability, low iron loss and low coercive force.

CONSTITUTION: This alloy consists of, by atom%, 68.0-70.0 Co, 2.5-4.0 Fe, 0-3 Ni, 1-4 Mn, 10-12 B and 14-15 Si, has a composition of (Fe+Ni)/(Co+Fe+ Mn)=0.07-0.09, and at least 70% of the alloy is vitreous and the alloy has the saturated magnetrostriction of -1×10^-6 to +1×10^-6, Curie temp. of 245-310°C, primary crystallization temp. of 530-575°C and saturation magnetic induction of 0.65-0.80 tesla.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to glassy alloys exhibiting near zero magnetostriction that are particularly suitable for use in high frequency applications.

[0002]

DESCRIPTION OF THE PRIOR ART Saturation magnetostriction λ _s relates to the change in length ratio Δl / l that occurs in a magnetic material that changes from a demagnetized state to a saturated ferromagnetic state. Magnetostrictive values, non-dimensional quantities are often given in units of microstrain (ie,
A small strain is a change in length ratio of 1 ppm). Low magnetostrictive ferromagnetic synthesis is desirable for several interrelated reasons.

1. Soft magnetism (low coercive force, high magnetic permeability) is generally obtained when the saturation magnetostriction λ _s and the magnetic crystal anisotropy k approach zero. Therefore, with the same anisotropy, lower magnetostrictive alloys exhibit lower dc coercivity and higher permeability. Such alloys are suitable for various soft magnetic applications.

2. The magnetism of a material with zero magnetostriction is not sensitive to mechanical strain. In this case, there is little need for winding, punching, or other post-physical treatment stress relief anneals required to form devices from such materials. In contrast, the magnetic properties of stress-sensitive materials such as crystalline alloys are significantly degraded by such cold working, and such materials must be carefully annealed.

3. When low coercive force and high magnetic permeability are realized (provided that the magnetic crystal anisotropy is neither too large nor the resistance is too small), a low dc coercive force of a material exhibiting a magnetostriction of 0 is brought to an ac operating state. . Since energy is not lost as mechanical vibration when the saturation magnetostriction is 0, the iron loss of the material exhibiting 0 magnetostriction is extremely low. Thus, when low loss and high ac magnetic permeability are required, a magnetic alloy having zero magnetostriction (low magnetic crystal anisotropy) is useful. Such applications include various tape winding and laminated core devices such as power transformers, signal converters, magnetic recording heads and the like.

4. As a result, electromagnetic devices containing materials with zero magnetostriction do not generate noise under AC excitation. This is the reason for the lower iron loss mentioned above, and at the same time is a desirable property in itself as it eliminates the hum inherent in many electromagnetic devices.

There are three well known crystalline alloys with zero magnetostriction (expressed in atomic% unless otherwise noted).

(1) nickel-iron alloy containing about 80% nickel ("80 nickel permalloy") (2) cobalt-iron alloy containing about 90% cobalt, and (3) containing about 6 wt% silicon. These are also iron-silicon alloy binary systems, but alloys with a magnetostriction of 0 added with a small amount of other elements such as molybdenum, copper or aluminum in order to change specific properties are also included in these types. These include, for example, 4% Mo, 7 with increased resistivity and permeability.
9% Ni, 17% Fe (Molly permalloy
Permalloy): Permalloy (sold under the name Mumetal) with varying amounts of soft magnetism and improved ductility copper added: 85 wt% Fe with zero anisotropy, 9 wt% Si , 6 wt% Al (sold under the name Sendust).

The alloys included in class (1) are the most commonly used of the above three classes because of their low anisotropy and zero magnetostriction and therefore their excellent soft magnetic properties: Indicates low coercive force, high magnetic permeability and low iron loss. These alloys are also relatively mechanically soft and have high temperatures (1000
The excellent magnetism obtained by annealing (above ℃) tends to deteriorate due to relatively light mechanical impact. Alloys of type (2), such as the Co ₉₀ Fe ₁₀ alloy, have a higher saturation magnetic induction (B _s about 1.9 Tesla) than permalloy. However, these alloys have a strong negative magnetocrystalline anisotropy that prevents them from being excellent soft magnetic materials. For example, C
The initial magnetic permeability of o ₉₀ Fe ₁₀ is only about 100 to 200.

Fe-6 wt% Si and related 3
Type (3) alloys such as the original alloy Sendust also exhibit higher saturation magnetic induction than Permalloy (B _s about 1.8 Tesla and 1.1 Tesla, respectively). However, these alloys are extremely brittle, so that limited use in powder form only has been found. Recently, Fe-6.5 wt% Si
[IEEE Trans. MAG-16 , 728 (19
80)] and Sendust alloy [IEEE Trans. M
AG-15 , J149 (1970)] was made relatively ductile by rapid solidification. However, the composition dependence of magnetostriction is extremely strong in these materials, and accurate tailoring (t) of the alloy composition for ensuring a magnetostriction of almost 0 is required.
ailing is difficult.

It is well known that magnetic crystal anisotropy is effectively eliminated in the glassy state. Therefore, it is desirable to find a glassy alloy with zero magnetostriction. Such alloys can be found in the vicinity of the composition. Due to the presence of metalloids, which tend to extinguish their magnetization by transferring charge to the transition metal d-electronic state, the glassy alloys of 80 nickel permalloy, at any rate, are non-magnetic at room temperature or have unacceptably low saturation magnetic induction. Show. For example, the vitreous alloy Fe ₄₀ Ni ₄₀ P ₁₄ B ₆ (subscripts are in atomic%) has a saturation magnetic induction of 0.8 Tesla. on the other hand,
Glassy alloy Ni ₄₉ Fe ₂₉ P ₁₄ B ₆ Si ₂ is about 0.46
Visible alloy Ni ₈₀ P ₂₀ with Tesla's saturation magnetic induction
Is non-magnetic. Non-glassy alloys with a saturation magnetostriction almost equal to 0 have not yet been found near the Fe-rich Sendust composition. Many of the glassy alloys having the magnetostriction of almost 0, which are composed of the Co—Fe crystalline alloy of the above (2), have been reported in the literature. These are, for example, Co ₇₂ Fe ₃ P ₁₆ B ₆ A
l ₃ [AIP Conference Proceed
ing, No. 24, pp. 745-746 (197)
5)], Co _70.5 Fe _4.5 Si ₁₅ B ₁₀ [Vol. 14,
Journal of Japan Society of Applied Physics, pp. 1077-1078 (19
75)], Co _31.2 Fe _7.8 Ni _39.0 B ₁₄ Si ₈ [Pr
ocedings of 3rd Internet
Ional Conference on Rapid
ly Quenched Metals, p. 183
(1979)] and Co ₇₄ Fe ₆ B ₂₀ [IEEE Tr
ans. MAG-12, 942 (1976)].
Table 1 lists some of the magnetic properties of these materials.

[0012] The saturation magnetic induction (B _s ) of these alloys is 0.6 to 1.2.
Tesla. The glassy alloy showing B _s, which is close to 0.6 T, has lower coercive force and higher magnetic permeability than crystalline supermalloy. However, these alloys tend to be magnetically unstable at relatively low temperatures (150 ° C). On the other hand, glassy alloy to B _s 1.2 Tesla first
It tends to have a ferromagnetic Curie temperature (θ _f ) near or above the secondary crystallization temperature (T _cl ). This makes the heat treatment of these materials extremely difficult to obtain the desired soft magnetism, since the annealing is most effective when carried out at temperatures close to θ _f .

Recent Prior Art [Journal of Applied Physics, 53 , 7819 (1983)]
Announces a glassy alloy with almost zero magnetostriction that exhibits excellent soft magnetism and magnetic stability. These glassy alloys are designed with the idea of the highest possible saturation magnetic induction. Recent trends in applied magnetism do not necessarily require high saturation magnetic induction, but rather high squareness ratio, low ac core loss at high frequencies and high permeability. From this viewpoint, glassy alloys exhibiting such properties are desirable.

SUMMARY OF THE INVENTION According to the present invention, there is provided a magnetic alloy which is at least 70% vitreous, has a magnetostriction of almost 0, is highly magnetically and thermally stable, and exhibits excellent soft magnetism at high frequencies. It The glassy alloy has the composition _{Co a Fe b Ni c Mn d} B e Si f. Subscripts here are atomic% and "a" is 6
The range is 8.0 to 70.0, and “b” is 2.5 to 4.
0 range, "c" range 0-3, "d"
Is in the range of 1 to 4, "e" is in the range of 10 to 12, and "f" is in the range of 14 to 15. The vitreous alloy has a saturation magnetostriction value in the range of -1 × 10 ^-6 to + 1 × 10 ^-6 ,
65-0.80 Tesla saturated magnetic induction, 245-310
It has a Curie temperature in the range of 0 ° C and a primary crystallization temperature in the range of 530-575 ° C.

DESCRIPTION OF THE INVENTION According to the present invention, at least 70% is glassy, has a magnetostriction of almost 0, is highly magnetically and thermally stable, and has high magnetic permeability, low iron loss and low coercive force. A magnetic alloy having a combination of excellent properties is provided. The glassy alloy has the composition _{Co a Fe b Ni c Mn d} B e Si f.
Here, the subscript is atomic% and "a" is 68.0.
70.0 range, "b" is 2.5-4.0 range, "c" is 0-3 range, and "d" is 1-4 range.
And "e" is in the range of 10-12,
“F” is in the range of 14-15. Glassy alloy is -1
Saturation magnetostriction value in the range of ^{x10 -6} to +1 x 10 ^-6 , 0.65
~ 0.80 Tesla saturation magnetic induction, Curie temperature in the range 245-310 ° C and first in the range 530-575 ° C.
It has a sub-crystallization temperature.

The purity of the composition is that of conventional commercial practice. 2 atom% of (Si + B) can be replaced by carbon, aluminum or germanium without significantly degrading the desired magnetism of these alloys.

Some magnetic and thermal properties of the near zero magnetostrictive glassy alloys of the present invention are listed in Table 2.

[0018] The presence of the metallic element Mn increases T _cl and therefore the thermal stability of the alloy system. A Mn content above 4 atom%, however, reduces the Curie temperature to a level below 245 ° C, which is not desirable in conventional magnetic devices.

For some applications, the use of materials with micro + or micro-magnetostriction is desirable or acceptable. In that case, all glassy alloys of Table 2 which exhibit saturation magnetostriction values in the range -1 x 10 ^-6 to +1 x 10 ^-6 are suitable. Magnetostriction value is (Fe + Mn) / (Co + Fe + Mn)
It is essentially determined by the ratio of. These ratios are 0.07 to 0.09.

The glassy alloys of the invention are conveniently prepared by other readily available techniques: eg 197.
U.S. issued on November 5, 4th. S Patent 3,845,8
05 and U.S. See S Patent 3,856,513. Generally, vitreous alloys in the form of continuous ribbons, wires, etc. are rapidly cooled from a melt of the desired composition at a cooling rate of at least about 10 ⁵ K / sec.

Boron in the range of 10 to 12 atomic% and silicon in the range of 14 to 15 atomic% of the total alloy composition, a total of 24
A metalloid content of boron and silicon of ˜27 atomic% is sufficient for glass formation.

Tables 3 and 4 show the magnetic permeability (μ) and the exciting force of the glass alloy of the present invention annealed at various temperatures (T ₀ ) at a magnetostriction of almost 0 at 50 kHz and 0.1 Tesla. (P ₈ ) and ac iron loss (L) are shown. In summary, by virtue of the water cooling after heat treatment shown in Table 3, the glassy alloys of this invention average L = 4 W / kg, P ₈ = 6 VA.
/ Kg, and μ = 28,000. The gradual cooling after the heat treatment generally has high loss and exciting force, and has low magnetic permeability. When heat-treated and then annealed, some glassy alloys of the present invention, in any case, outperform or are comparable to those exhibited by the heat-treated and quenched material.

Examples of glassy alloys outside the scope of this invention are listed in Table 5. The beneficial combination of properties provided by the alloys of the present invention cannot be obtained with prior art non-magnetostrictive vitreous alloys with high saturation magnetic induction, such as Co ₇₄ Fe ₆ B ₂₀ . Because their Curie temperature is higher than the primary crystallization temperature and heat treatments to improve the properties are not effective in those with low saturation magnetic induction. The above properties obtained by the glassy alloys of the present invention may be obtained by prior art low magnetic induction glassy alloys. Anyway, Co _31.2 Fe _7.8 −
_Prior art alloys such as Ni _39.0 -B ₁₄ Si ₈ are susceptible to magnetic instability at relatively low temperatures of about 150 ° C., as mentioned above. The excellent combined properties of other prior art glassy alloys are Co _67.4 Fe _4.1 Ni _3.0 Mo _1.5 which is a glassy alloy annealed at 380 ° C. for 15 minutes and then quenched.
Obtained in _{-B 12.5 Si 11.5 L = 4W /} kg, P 8 = 7
VA / kg and μ = 23,000. It is clear that the glassy alloys of the invention are generally superior to this class of glassy alloys.

[0024] In Table 5, Co _a Fe _b N in which at least one of a, b, c, d, e and f falls outside the composition range defined by the present invention.
of i _c Mn _d Some exemplary glassy alloys of the composition of B _e Si _f shows the magnetic properties. This table lists that alloys having at least one of the components outside the limited range show that either the Curie temperature or the saturation magnetic induction is too low to be practical for many magnetic applications. .

The following example is presented to provide a more complete understanding of the invention. Specific techniques, conditions, materials, ratios and reported data are presented to explain the principle,
The practice of this invention serves as an example and should not be construed as limiting the scope of this invention.

Example 1. Sample Preparation The glassy alloys listed in Tables 2-5 are U.V. S Patent 3,85
The melt was quenched (about 10 ⁶ K / sec) according to the technique taught by Chen and Pork of 6,513. The resulting ribbon, typically 25-30 μm thick and 0.5-2.5 cm wide, was determined by X-ray diffractometry (using CuK radiation) and scanning calorimetry to lack effective crystallinity. . The glassy alloy ribbon was strong, shiny, hard and ductile.

2. Magnetism Measurement A closed ribbon of a continuous ribbon of glassy alloy prepared according to the procedure described in Example 1.
Bobbin (3.-path) to form an annular sample.
8 cmO. D. ). Each sample contained 1-3 g of ribbon. Insulated primary and secondary windings (each counting at least 10) were applied annularly. These samples were tested using a commercial curve tracer for initial permeability and hysteresis loops (coercive force and remanence) and iron loss (IEEE).
Used to obtain standards 106-1972).

The saturation magnetization M _s ′ of each sample was measured using a commercial vibration sample magnetometer (Princeton Applied Research Laboratory).
In this case, the ribbon is some small squares (approximately 2
mm × 2 mm). These are arbitrarily oriented around the standard direction and their planes are
720 kA / m). Saturation magnetic induction B _s (=
4π4M _s D) was calculated by using the measured mass density D.

The ferromagnetic Curie temperature (θ _f ) was measured by the inductance method and was also monitored by differential scanning calorimetry, which is mainly used to determine the crystallization temperature. The first or first crystallization temperature (T _cl ) was used to compare the thermal stability of the various glassy alloys of the _instant and prior art inventions.

Magnetic stability is described in Journal of Applied Physics, Vol. 49, p. 6510
Reorientation kinetics of magnetization according to the method described in (1978).
s). The method is shown therein by reference thereto. Magnetostriction measurements used a metal strain gauge (BLH Electronics) bonded (Eastman-910 cement) between two short lengths of ribbon. The ribbon axis and the gauge axis were parallel. Magnetostriction is
According to the formula λ = 2/3 [(Δl / l)-(Δl / l)], parallel to the flat magnetic field (Δl / l) and perpendicular (Δl / l)
It was determined as a function of the applied magnetic field from the length strain in l). Since the invention has been described in considerable detail, it is not necessary to strictly adhere to this detailed description, and all further modifications and alterations that fall within the scope of the invention as defined by the appended claims will occur to those skilled in the art. Can be suggested.

Claims (7)

[Claims] 1. A formula _{Co a Fe b Ni c Mn d} B e Si f
And the subscript in the formula is atomic% and a is 68.0.
Is in the range of 70.0, b is in the range of 2.5 to 4.0, c is in the range of 0 to 3, d is in the range of 1 to 4, and e is in the range of 10 to 12. And f is in the range of 14 to 15 and (Fe + Mn) / (Co + Fe + Mn)
Ratio is 0.07-0.09, at least 70% glassy ^{alloy, -1 × 10 -6 ~ + 1} × 10 -6 for values of saturation magnetostriction, in the range of 245 ° C. to 310 ° C. Curie A magnetic alloy having a temperature of 530 ° C. to 575 ° C., a primary crystallization temperature, and a saturation magnetic induction of 0.65 to 0.80 Tesla. 2. The magnetic alloy according to claim 1, having a composition of Co _68.2 Fe _3.8 Mn ₁ B ₁₂ Si ₁₅ . 3. The magnetic alloy according to claim 1, having a composition of Co _67.7 Fe _3.3 Mn ₂ B ₁₂ Si ₁₅ . 4. The magnetic alloy according to claim 1, having a composition of Co _70.0 Fe _4.0 Mn ₁ B ₁₀ Si ₁₅ . 5. The magnetic alloy according to claim 1, having a composition of Co _69.5 Fe _3.5 Mn ₂ B ₁₀ Si ₁₅ . 6. The magnetic alloy according to claim 1, having a composition of Co _69.0 Fe _3.0 Mn ₃ B ₁₀ Si ₁₅ . 7. The magnetic alloy of claim 1 having a composition of Co _68.5 Fe _2.5 Mn ₄ B ₁₀ Si ₁₅ .