JPH0338334B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to vitrified metal alloys with near-zero magnetostriction, high magnetic and thermal stability, and excellent soft magnetic properties. Description of the Prior Art Saturation magnetostriction λs refers to the rate of change in length that occurs in a magnetic material in the transition from a demagnetized state to a saturated ferromagnetic state, Δl/l. The value of magnetostriction is a dimensionless quantity, but is often expressed in units of microstrain (where microstrain is the rate of change in length in ppm). Ferromagnetic alloys with low magnetostriction are desired for several interrelated reasons. 1 Soft magnetism (low coercivity, high permeability) is generally obtained when both the saturation magnetostriction λ _s and the magnetocrystalline anisotropy constant K are close to zero. Therefore, if the anisotropy is the same, an alloy with lower magnetostriction will exhibit lower DC coercive force and higher magnetic permeability. Such alloys are suitable for a variety of soft magnetic applications. 2 The magnetism of such near-zero magnetostrictive materials is insensitive to mechanical strain. In such cases, there is little need for strain relief annealing after bending, stamping, or other physical procedures necessary to make devices from such materials. In contrast, the magnetic properties of strain-sensitive materials such as crystalline alloys are significantly degraded by such cold working. Such materials must therefore be carefully annealed. 3 The low DC coercivity of zero magnetostrictive materials is carried over to AC operating conditions, where they again exhibit low coercivity and high permeability (provided that the crystalline magnetic anisotropy is not too large and the electrical resistance is too small). ). Furthermore, when the saturation magnetostriction is zero, the energy is not affected by mechanical vibrations, so the core loss of the zero magnetostrictive material is quite low. Zero magnetostrictive magnetic alloys (with moderate or low magnetocrystalline anisotropy) are thus useful where low core losses and high AC permeability are required. Such applications include various wound tapes, layered core devices such as power transformers, communications transformers, magnetic recording heads, and the like. 4. Finally, electromagnetic devices with zero magnetostrictive materials do not generate acoustic noise upon alternating current excitation.
This is due to the low magnetic core loss mentioned above, but is also an inherently necessary property since it eliminates the inherent beat in many electromagnetic devices. Three crystalline alloys are well known as having zero magnetostriction (hereinafter in atomic percent unless otherwise noted). (1) Nickel-iron alloys containing about 80% nickel ("80 nickel permalloy"), (2) cobalt-iron alloys containing about 90% cobalt, and (3) iron-silicon alloys containing about 6% silicon by weight. This category also includes zero magnetostrictive alloys, which are binary based alloys with the addition of small amounts of other elements, such as molybdenum or aluminum, to modify specific properties. These include, for example, Δ% with increased electrical resistance and magnetic permeability.
Mo, 79% Ni, 17% Fe (Molypermalloy; Moly
permalloy with varying amounts of copper added to improve soft magnetism and ductility (sold under the name Mumetal),
and 85% Fe, 9% Si, and 6% Al (commercially available under the name Sendust) with zero anisotropy. Alloys in category (1) are the most widely used of the three listed above. This is because they have both zero magnetostriction and low anisotropy, and are therefore extremely magnetically soft. That is, they have low coercive force, high permeability and low core loss. These permalloys are also mechanically relatively soft, and their excellent magnetic properties obtained by annealing at high temperatures (above 1000° C.) are susceptible to deterioration even by relatively light mechanical shock. Alloys in _category (2), such as those based on _Co90Fe10 , have even higher saturation flux densities (Bs approximately 1.9 Tesla) than permalloy. However, they also have strong negative magnetocrystalline anisotropy, which prevents them from being good soft magnetic materials. For example, the initial permeability of Co ₉₀ Fe ₁₀ is approximately 100 to 200
It's nothing more than that. Category (3) such as 6 wt% Si-Fe and related ternary alloy Sendust (described above) also have higher saturation flux densities (respectively about Bs) than permalloy.
1.8 terraces and 1.1 Tesla). However, these alloys are extremely brittle and are therefore limited to use only in powder form. Recently 6.5wt%Si−
Fe [IEEE Trans.MAG-16728 (1980)] and Sendust alloy [IEEE Trans.MAG-15, 1149]
(1970)] both became relatively ductile through rapid solidification. However, the component dependence of magnetostriction is very strong in these materials, and it is difficult to carefully adjust the alloy composition to provide magnetostriction close to zero. It is known that magnetocrystalline anisotropy is effectively removed in the vitrified state. It would therefore be desirable to look for vitrified metal alloys that have zero magnetostriction. Such alloys may be found close to the compositions described above. However, the presence of metalloids tends to suppress magnetization due to charge transfer to the d-electron state of transition metals.
Vitrified metal alloys based on 80 nickel permalloy are either non-magnetic at room temperature or have unacceptable low saturation magnetic flux densities. For example vitrified metal alloys
Fe ₄₀ Ni ₄₀ P ₁₄ B ₆ (the attached figures are in atomic percent) has a saturation flux density of about 0.8 Tesla, while the vitrified alloy Ni ₄₉ Fe ₂₉ P ₁₄ B ₆ Si ₂ has a saturation flux density of about 0.46 Tesla Density and also vitrified alloy Ni ₈₀ P ₂₀
is non-magnetic. A vitrified metal alloy with a saturation magnetostriction approximately equal to zero has not yet been found close to the composition of iron-rich sendust. Many near-zero magnetostrictive vitrified metal alloys based on the Co-Fe crystalline alloy in (2) above have been reported in the literature. For example, these are Co ₇₂ Fe ₃ P ₁₆ P ₆ Al ₃ (AIP
Conference Proceedings, No. 24, pp. 745-746
(1975)), Co _70.5 Fe _4.5 Si ₁₅ B ₁₀ (Vol.14, Japanse
Journal of Applied Physics.pp.1077〜1078
(1975)), Co _31.2 Fe _7.8 Ni _39.0 B ₁₄ Si ₈ [Proceedings
of 3rd International Conference on Rapidly
Quenched Metals, p.183, (1979)] and
Co ₇₄ Fe ₆ B ₂₀ [IEEE Trans.MAG−12, 942
(1976)]. Table 1 lists some of the magnetic properties of these materials.

【table】

[Table] The saturation magnetic flux density (Bs) of these alloys ranges from 0.6 to 1.2 Tesla. Vitrified alloys with Bs close to 0.6 Tesla exhibit lower coercivity and permeability than crystalline supermalloy. However, these alloys tend to be magnetically unstable at relatively low temperatures (150°C). In contrast, vitrified alloys below 1.2 Tesla tend to have their ferromagnetic Curie temperatures (θ) near or above their primary crystallization temperatures (Tcl). This makes it very difficult to obtain the necessary soft magnetism by heat treating these materials. This is because such annealing is most effective when performed at temperatures near θ. Clearly, there is a need for zero magnetostrictive vitrifying alloys with higher magnetic and thermal stability and as high a saturation flux density as possible. SUMMARY OF THE INVENTION In accordance with the present invention, an alloy is obtained that is at least 70% vitrified magnetic alloy, has near-zero magnetostriction, high magnetic and thermal stability, and excellent soft magnetism. The glassy magnetic metal alloy of the present invention has the formula Co _a Fe _{b Nic} Mo _d B _{e Sif} (where a is 58 to 70 at%, b is 2 to 7.5 at%,
c is 8 at% or less, d is 1 to 2 at%, e is 11 to
15 at%, f shall be within the range of 9 to 14 at%, provided that the sum of a+b+c is 72 to
76 atomic%, provided that the sum of e+f is within the range of 23 to 26 atomic%) or the formula Co _a Fe _b Mo _d B _e Si _f (where a is 58 to 70 atomic% and b is 2 ~7.5 atom%,
d is 1 to 2 atom%, e is 11 to 15 atom%, f is 9 to 2 atom%
14 atomic %, provided that the sum of a+b is within the range of 72 to 76 atomic %, and the sum of e+f is within the range of 23 to 26 atomic %). The glassy alloy of the present invention has the following properties. (a) magnetostriction value between −1.1×10 ^-6 and +1.1×10 ^-6 ; (b) saturation magnetic flux density equal to or greater than 0.6 T; (c) not exceeding 0.56 A/m. DC coercivity, (d) Magnetic permeability at 0.1T, 50kHz, which is at least 8200. It further has a Curie temperature in the range of about 550-670K and a primary crystallization temperature in the range of about 790-870K. DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a magnetic alloy with at least 70% vitrification and close to zero magnetostriction, high magnetic and thermal stability, high magnetic permeability, low core loss and low The result is an alloy with a remarkable combination of properties including coercivity and soft magnetism. The glassy magnetic metal alloy of the present invention has the formula Co _a Fe _{b Nic} Mo _d B _{e Sif} (where a is 58 to 70 at%, b is 2 to 7.5 at%,
c is 8 at% or less, d is 1 to 2 at%, e is 11 to
15 at%, f shall be within the range of 9 to 14 at%, provided that the sum of a+b+c is 72 to
76 atomic%, provided that the sum of e+f is within the range of 23 to 26 atomic%) or the formula Co _a Fe _b Mo _d B _e Si _f (where a is 58 to 70 atomic% and b is 2 ~7.5 atom%,
d is 1 to 2 atom%, e is 11 to 15 atom%, f is 9 to 2 atom%
14 atomic %, provided that the sum of a+b is within the range of 72 to 76 atomic %, and the sum of e+f is within the range of 23 to 26 atomic %). The glassy alloy of the present invention has the following properties. (a) magnetostriction value between −1.1×10 ^-6 and +1.1×10 ^-6 ; (b) saturation magnetic flux density equal to or greater than 0.6 T; (c) not exceeding 0.56 A/m. DC coercivity, (d) Magnetic permeability at 0.1T, 50kHz, which is at least 8200. Furthermore, it has a Curie temperature in the range of 550-670K and a primary crystallization temperature in the range of approximately 790-870K. The purity of the above components is that found in normal commercial practice. However, it should be noted that the molybdenum in the alloys of the invention can be replaced by at least one of the other transition metal elements such as tungsten, niobium, tantalum, titanium, zirconium and hafnium, and the necessary magnetic properties of these vitrified alloys. It will be appreciated that up to about 2 atomic percent of the Si can be replaced by carbon, aluminum, or germanium without significantly degrading the Si. The essential zero magnetostrictive vitrified metal alloys of the present invention include Co _67.4 Fe _4.1 Ni _3.0 Mo _1.5 B _12.5 Si _11.5 ,
Co _67.1 Fe _4.4 Ni _3.0 Mo _1.5 B _12.5 Si _11.5 , Co _64.0 Fe _4.5 Ni _6.0
Mo _1.5 B _12.5 Si _11.5 , Co _67.0 Fe _4.5 Ni _3.0 Mo _1.5 B ₁₂ Si ₁₂ ,
Co _67.0 Fe _4.5 Ni _3.0 Mo _1.5 B ₁₃ Si ₁₁ and Co _67.5 Fe _4.5
There are Ni _3.0 Mo _1.0 B ₁₂ Si ₁₂ . These vitrified alloys have a saturation magnetic flux density of about 0.7-0.8 Tesla, 600-670K
It has a Curie temperature of about 800K, a primary crystal temperature of about 800K, and excellent ductility. Some magnetic and thermal properties of these and other near-zero magnetostrictive vitrifying alloys of the present invention are listed in Table 2. These compare well with the properties listed in Table 1 for the zero magnetostrictive vitrified metal alloys previously reported.

【table】

[Table] Activation energy (Ea) for magnetization rearrangement
are listed in Table 3 for some representative near-zero magnetostrictive vitrification alloys. This table shows that Si tends to increase Ea and that Ea also tends to increase as the Si/B ratio approaches 1. It is desirable to show that the higher the value of Ea, the higher the magnetic stability of the system. Combining these findings based on Tables 2 and 3, the preferable amount of Si is (Si+B).
When it is 23-26 atomic percent, it becomes 9-14 atomic percent. The presence of Mo increases the Tcl and thus the thermal stability of this alloy system. A range of 1 to 2 atomic % is suitable. However, Mo exceeding 2 atomic percent
This amount lowers the Curie temperature to below 550 K, which is undesirable for normal magnetic devices.

Table: For some applications it is desirable or acceptable to use materials with slightly positive or slightly negative magnetostriction. Such a zero-near magnetostrictive vitrified metal alloy has a, b and c of 58 to 702, respectively.
a, in the range of 7.5 and 0 to 8 atomic percent;
Provided that the sum of b and c is in the range of 72 to 76 atomic percent. The absolute value of the saturation magnetostriction |λ _s | of these glassy metal alloys is less than 1.1×10 ⁻⁶ (i.e. the saturation magnetostriction range is from −1.1×10 ⁻⁶ to +1.1×10 ⁻⁶ or − (within a range of 1 to +1 microstrain). The saturation magnetic flux density of these glassy metal alloys is equal to or greater than 0.6 Tesla, and generally ranges from 0.6 to 0.8 Tesla. The value of λs that is even closer to zero makes the values of a, b, and c 63 to 69, 3 to 6, and 0 to 6, respectively.
range, where the sum of a, b and c is approximately 72 to 76
Obtained when the range is in atomic percent. With such a recommended composition, |λs| becomes 0.5×10 ^-6 or less. The essential magnetostriction zero values range from 64 to 68, 4 to 5, and 0 to 6 atomic percent for values of a, b, and c, respectively, such that the sum of a, b, and c is approximately 72 to 76 in the atomic percent range, and f is 11
~12 atomic percent and when (e+f) is close to 24 atomic percent. Such components are therefore most preferred. The vitrified metal alloys of the present invention are conveniently made using techniques readily used elsewhere. For example in 1974
U.S. Patent No. 3,845,805 issued November 5th and 1974
See U.S. Pat. No. 3,856,513, issued December 24, 2013. The vitrified alloy, generally in the form of a continuous ribbon, cotton, etc., is rapidly cooled from a molten metal of the required composition at a rate of at least about 105 K/sec. The semimetallic components of boron and silicon in the range of 23 to 26 atomic percent of the total alloy composition are sufficient to form vitrification with boron in the range of 11 to 15 atomic percent and silicon in the range of 9 to 14 atomic percent. . As mentioned above, a Si/B ratio close to 1 and a silicon content ("f") of 11 to 12 atomic percent are most preferred. This is because they provide higher stability and the magnetostriction (close to zero) is relatively insensitive to the semimetallic composition. For example, a=67.1b=4.5, c=3.0 and d
= 1.5 atomic percent, the rate of change in magnetostriction with respect to silicon content |dλs/df| is approximately 0.8×10 ^-6 /at % near f = 10 or 13 atomic percent.
For Si, dλs/df is close to zero for f between 11 and 12 atomic percent. a=67.8, b=3.7, c
=3.0 and d=1.5 atomic percent, then f=
Near 12 atomic percent, the amount |dλs/df| becomes zero, and near f=10 or 13 atomic percent it becomes about 0.1×10 ⁻⁶ /Si atomic percent. A small amount of Ni is relatively ineffective in changing the magnetostriction value in this alloy system, and is essentially Co:
The Fe ratio determines the resulting magnetostriction value. Zero magnetostriction is obtained in the present alloy system when the Co:Fe ratio is about 14-16.5:1. Co _70.5 Fe _4.5 B ₁₀ Si ₁₅ and
In prior art vitrified metal alloys such as Co ₇₄ Fe ₆ B ₂₀ , the ratios are set at approximately 14 and 12, respectively. approximately 14:1 near f = 11.5 atomic percent to obtain λs = 0 and dλs/df = 0
The above Co:Fe ratio range between ~16.5:1 and about ±
Taking a tolerance of 0.5 atomic percent is beneficial from a material integrity standpoint. Table 4 shows AC core loss at 0.1 Tesla magnetic flux density and 50 KHz for near-zero magnetostrictive vitrified alloys of the present invention annealed at different temperatures (Ta).
(L), excitation power (Pe) and magnetic permeability (μ).

[Table] Table 5 shows DC coercive force (Hc), residual magnetic flux density (Br), AC coercive force (Hc') and squareness ratio (Br/
Annealing temperature (Ta) applied to Bl) and annealing magnetic field (Hll) applied in the circumferential direction of the toroidal sample
This shows the effect of Here, Bl is the magnetization of one of the zero magnetic alloys of the present invention when a magnetic field of 10e is applied at 50 KHz, and μ is the magnetization at 50 KHz and 0.1 Tesla. Low coercivity at high frequencies and high squareness ratios close to unity are desirable for magnetic device applications such as power switches.

【table】

[Table] Table 6 shows the annealing time (Ta) on L, Pe, and μ for one of the zero magnetostrictive alloys of the present invention.
This shows the effect of

[Table] From the results shown in Tables 4 to 6 above, it is clear that the present invention
For zero magnetostrictive vitrified alloys 25-30 μm thick, L = 4 W/ at 0.1 Tesla and 50 KHz.
It is noted that Kg, Pe=7Va/Kg and μ=23000 are obtained. Compared to these numbers, a prior art crystalline non-magnetostrictive supermalloy of similar thickness (25 μm) has L = 8 W/ at 0.1 Tesla and 50 KHz.
Kg, Pe=10VA/Kg and μ=19000. It is clear that the properties of the non-magnetostrictive vitrifying alloy of the present invention are superior to those of crystalline supermalloy. Examples of amorphous alloys outside the scope of the invention are shown in Table 7. The advantageous combination of properties provided by the alloys of the present invention is not available with prior art non-magnetostrictive glass alloys with high saturation flux densities such as Co ₇₄ Fe ₆ B ₂₀ . This is because their Kyrie temperature is higher than the primary crystal temperature,
Heat treatments to improve their properties are not as effective as those with lower saturation flux densities. The above properties obtained in the vitrifying alloys of the present invention are also obtained in prior art low magnetization vitrifying alloys. However, these prior art alloys such as Co _31.2 Fe _7.8 Ni _39.0 B ₁₄ Si ₈ tend to become magnetically unstable at relatively low temperatures of about 150° C., as previously pointed out.

[Table] Table 7 shows representative vitrification alloys with the composition Co _a Fe _b Ni _c Mo _d B _e Si _f , and their a, b, c, d, e and f.
The graph shows some magnetic properties when at least one of the above is outside the composition range defined in the present invention.
The table points out that alloys in which at least one of the components is outside the specified range exhibit at least one of the following undesirable properties: () The value of |λs| is greater than 1×10 ^-6 . () The Curie temperature (θf) is the crystallization temperature (Tcl)
higher than Crystallization reduces the effectiveness of magnetic field annealing for machining. and () the Curie temperature and saturation magnetic flux density (Bs) are too low to be practical. The following examples are presented to provide a more complete understanding of the invention. Specific techniques, conditions, and materials to clarify the principles and practices of the invention;
Ratios and reported data are typical;
It should not be construed as limiting the scope of the invention. Example 1 Sample Preparation The vitrified alloys listed in Tables 2-7 were rapidly cooled (approximately 10 ⁶ K) from a molten metal according to the technique taught by Chen and Polk in U.S. Pat. /second). The resulting ribbons were typically 25-30 μm thick, 0.5-2.5 cm wide, and were confirmed to be free of significant crystals by X-ray diffraction (using Cuk radiation) and scanning calorimetry. Vitrified metal alloy ribbons are strong, shiny, hard and ductile. 2 Magnetic measurements A continuous ribbon of vitrified metal alloy made according to the method described in 1 above was wound around a bobbin (outer diameter 3.8 cm) to form a closed magnetic circuit toroidal sample. Each sample contains 1-3 g of ribbon. The toroid (wound core ring) had primary and secondary windings (at least 10 turns each) of insulated wire. These samples were used to determine the hysteresis curve (coercive force and residual magnetic flux density), initial permeability, and core loss using a commercially available curve tracer (IEEE
According to Standard 106−1972). The saturation magnetization Ms of each sample was also measured using a commercially available vibrating sample magnetometer (manufactured by Princeton Applied Research). In this case the ribbon was cut into several small square pieces (approximately 2 mm x 2 mm).
These are normally oriented randomly, and their faces are exposed to an applied magnetic field (0 to 720 KA/m).
It was assumed that they were parallel. Then, the saturation magnetic flux density Bs (=4πMsD) was calculated using the measured quantity density D. The ferromagnetic Curie temperature (θf) was measured by the inductance method and examined by differential scanning calorimetry. This calorimeter was mainly used to check the crystallization temperature. The primary crystal temperature or primary crystal temperature (Tcl) was used to compare the thermal stability of various vitrified alloys in the present invention and prior art inventions. Magnetic stability Journal of Applied
This was confirmed from the magnetization rearrangement dynamics according to the method described in Physics. Vol. 49, p. 6510 (1978) (combining this method with those from the literature). Metal strain gauges (BLH) are used for magnetostriction measurements.
Electronics) was used. I pasted this between two short pieces of ribbon (Eastman-910
(by cement). The ribbon axis and gauge axis are parallel. Magnetostriction is the longitudinal strain in a flat field (Δl/l)
From ‖ and perpendicular strain (Δl/l) ⊥, formula λ = 2/3
It was determined as a function of the applied magnetic field according to [(Δl/l) ‖−(Δl/l) ⊥]. Although the present invention has thus been described in rather sufficient detail, it is not necessary to dwell on this detail; further changes and improvements hereafter will be apparent to those skilled in the art as defined by the appended claims. It will be understood that the invention can be accepted as falling within the scope of the invention as described above.

Claims (1)

[Claims] 1 Formula: Co _a Fe _b Ni _c Mo _d B _e Si _f (wherein a is 58 to 70 atomic %, b is 2 to 7.5 atomic %,
c is 8 at% or less, d is 1 to 2 at%, e is 11 to
15 at%, f shall be within the range of 9 to 14 at%, provided that the sum of a+b+c is 72 to
76 atomic %, provided that the sum of e+f is within the range of 23 to 26 atomic %), and (a) has a magnetic field between -1.1×10 ^-6 and +1.1×10 ^-6 strain value; (b) saturation magnetic flux density equal to or greater than 0.6 T; (c) DC coercivity not exceeding 0.56 A/m; (d) permeability at 0.1 T, 50 kHz which is at least 8200. It has high magnetic and thermal stability and has almost zero magnetostriction.
A magnetic metal alloy that is at least 70% glassy. 2 Claim 1 in which a is within the range of 63 to 69 at%, b is within the range of 3 to 6 at%, and c is within the range of 6 at% or less
Magnetic alloys described in section. 3 When f is between 11 and 12 atomic % and the sum of e and f is close to 24 atomic %, a is
64 to 68 atom%, b 4 to 5 atom%, c 6 atom%
A magnetic alloy according to claim 1 falling within the following range. 4. A magnetic alloy according to claim 3 having the formula Co _67.4 Fe _4.1 Ni _3.0 Mo _1.5 B _12.5 Si _11.5 . 5. A magnetic alloy according to claim 3 having the formula Co _67.1 Fe _4.4 Ni _3.0 Mo _1.5 B _12.5 Si _11.5 . 6. A magnetic alloy according to claim 3 having the formula Co _64.0 Fe _4.5 Ni _6.0 Mo _1.5 B _12.5 Si _11.5 . 7. A magnetic alloy according to claim 3 having the formula Co _67.0 Fe _4.5 Ni _3.0 Mo _1.5 B ₁₂ Si ₁₂ . 8. A magnetic alloy according to claim 3 having the formula Co _67.0 Fe _4.5 Ni _3.0 Mo _1.5 B ₁₃ Si ₁₁ . 9. A magnetic alloy according to claim 3 having the formula Co _67.5 Fe _4.5 Ni _3.0 Mo _1.0 B ₁₂ Si ₁₂ . 10 Formula Co _a Fe _b Mo _d B _e Si _f (In the formula, a is 58 to 70 at%, b is 2 to 7.5 at%,
d is 1 to 2 atom%, e is 11 to 15 atom%, f is 9 to 2 atom%
(with the condition that the sum of a+b is within the range of 72 to 76 atom%, and the sum of e+f is within the range of 23 to 26 atom%), and ( a) magnetostriction values between −1.1×10 ^-6 and +1.1×10 ^-6 ; (b) saturation magnetic flux density equal to or exceeding 0.6 T; (c) direct current not exceeding 0.56 A/m. Coercivity, (d) Magnetic permeability at 0.1T, 50kH, which is at least 8200. A glassy metal alloy having high magnetic and thermal stability and almost zero magnetostriction, characterized by having the following properties. 11. The magnetic alloy according to claim 10, wherein a is in the range of 63 to 69 atom % and b is in the range of 3 to 6 atom %. 12 f is between 11 and 12 atom%, and e and f
When the total of a and is nearly 24 at%,
11. The magnetic alloy according to claim 10, wherein b is in the range of 64 to 68 atomic % and b is in the range of 4 to 5 atomic %.