JP2697808B2 - Vitreous alloy with almost zero magnetostriction for high frequency use - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a vitreous alloy exhibiting near zero magnetostriction which is particularly suited for use in high frequency applications. 2. Description of the Prior Art Saturated magnetostriction λ _S relates to a change in the ratio of length 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 micro-strain (ie,
Microstrain is a 1 ppm length ratio change). Low magnetostrictive ferromagnetic alloys are desirable for several interrelated reasons. [0003] 1. Soft magnetism (low coercivity, high magnetic permeability) is generally obtained when the saturation magnetostriction λ _s and the magnetocrystalline anisotropy k approach zero. Therefore, at the same anisotropy, lower magnetostrictive alloys exhibit lower dc coercivity and higher permeability. Such alloys are suitable for various soft magnetic applications. [0004] 2. The magnetism of a material with zero magnetostriction is not sensitive to mechanical strain. In this case, little post-stress relief anneal is required after winding, punching or otherwise forming the device from such materials. On the other hand, the magnetism of stress-sensitive materials such as crystalline alloys is greatly degraded by such cold working, and such materials must be carefully annealed. [0005] 3. When low coercivity and high permeability are achieved (provided the magnetocrystalline anisotropy is not too large and the resistance is not too low), a low dc coercivity of the material exhibiting zero magnetostriction is brought into the ac operating state. . Since energy is not lost as mechanical vibration when the saturation magnetostriction is 0, the iron loss of a material exhibiting 0 magnetostriction is extremely low. Thus, when low loss and high ac magnetic permeability are required, a magnetic alloy with zero magnetostriction (of low magnetic crystal anisotropy) is useful. Such applications include various tape wound and laminated core devices such as power transformers, signal transducers, magnetic recording heads, and the like. [0006] 4. As a result, an electromagnetic device including a material having zero magnetostriction does not generate noise under AC excitation. While this is the reason for the lower iron loss, it is also a desirable property in itself because it eliminates the hum inherent in many electromagnetic devices. There are three well-known crystalline alloys with zero magnetostriction (expressed in atomic% unless otherwise indicated). (1) a nickel-iron alloy containing about 80% nickel ("80 nickel permalloy"); (2) a cobalt-iron alloy containing about 90% cobalt; and (3) a silicon-iron alloy containing about 6% by weight silicon. Although these alloys are binary systems of iron-silicon alloys, alloys with zero magnetostriction added with small amounts of other elements such as molybdenum, copper or aluminum 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 (Moly
Permalloy (sold under the name of Permalloy): soft magnetic and improved ductility. Permalloy with an added amount of copper (sold under the name of Mumetal): 85% by weight of Fe with anisotropy of 0 and 9% by weight of Si. , 6% by weight Al (sold under the name Sendust). The alloys included in class (1) are the most commonly used of the three above because of their low anisotropy and zero magnetostriction, and therefore excellent soft magnetism: Indicates low coercive force, high magnetic permeability and low iron loss. These alloys are also relatively mechanically soft, and have high temperatures (1000
The superior magnetism obtained by annealing tends to be degraded by relatively light mechanical impact. Alloy type (2), such as Co ₉₀ Fe ₁₀ alloy has a higher saturation induction than Permalloy (B _s about 1.9 Tesla). However, these alloys have strong negative magnetocrystalline anisotropy which prevents them from being excellent soft magnetic materials. For example, C
The initial permeability of o ₉₀ Fe ₁₀ is only about 100 to 200. The above Fe-6 wt% Si and related 3
Alloy type (3) as the original alloy Sendust also shows higher saturation induction and (B _s about 1.8 Tesla and 1.1 Tesla, respectively) than Permalloy. However, these alloys are very brittle, and thus have found limited use in powder form only. Recently, Fe-6.5 wt% Si
[IEEE Trans. MAG-16 , 728 (19
80)] and sendust alloy [IEEE Trans. M
AG-15 , J149 (1970)] was produced relatively rapidly by rapid solidification. However, the composition dependence of magnetostriction is extremely strong in these materials, and accurate tailoring of alloy composition (t
ailing is difficult. It is well known that magnetocrystalline anisotropy is effectively eliminated in the glassy state. It is therefore desirable to find a vitreous alloy with zero magnetostriction. Such alloys can be found near the composition. Regardless, due to the presence of metalloids, which tend to annihilate magnetization by transferring charge to the transition metal d-electronic state, 80 nickel permalloy glassy alloys are either non-magnetic or have unacceptably low saturation magnetic induction at room temperature. Show. For example, glassy alloys _{Fe 40 Ni 40 P 14 B 6} ( the subscript is the atomic%) having a 0.8 Tesla saturation induction. on the other hand,
The glassy alloy Ni ₄₉ Fe ₂₉ P ₁₄ B ₆ Si ₂ is about 0.46
Visible alloy Ni ₈₀ P ₂₀ with saturation magnetic induction of Tesla
Is non-magnetic. Non-vitreous alloys with a saturation magnetostriction equal to approximately zero have not yet been found in the vicinity of Fe-rich Sendust compositions. Many of the vitreous alloys having a magnetostriction of almost zero made of the Co-Fe crystalline alloy of (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 the Japan Society of Applied Physics, pp. 1077-1078 (19
75)], Co _31.2 Fe _7.8 Ni _39.0 B ₁₄ Si ₈ [Pr
receiveds of 3rd Internet
ionical 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] Saturation induction of these alloys (B _s) is 0.6 to 1.2
Tesla. Near 0.6 T, glassy alloy exhibiting B _s denotes a low coercive force and high permeability as compared with the crystalline Supamaroi. However, these alloys tend to be magnetically unstable at relatively low temperatures (150 ° C.). On the other hand, vitreous alloys up to 1.2 _s
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 annealing is most effective when performed at temperatures close to θ _f . Recent Prior Art [Journal of Applied Physics, 53 , 7819 (1983)]
Announces a vitreous alloy with nearly zero magnetostriction that exhibits excellent soft magnetism and magnetic stability. These vitreous alloys are designed with the highest possible magnetic induction. Recent trends in applied magnetism do not necessarily require high saturation magnetic induction, but require high rectangular ratio, low ac iron loss at high frequencies and high magnetic permeability. From this viewpoint, a vitreous alloy exhibiting such properties is desirable. According to the present invention, at least 70% is vitreous, has almost zero magnetostriction, is magnetically and thermally highly stable, has high magnetic permeability, low iron loss, and low coercive force. A magnetic alloy exhibiting excellent soft magnetism at high frequencies having an excellent combination of properties is provided. The vitreous alloy is Co _a Fe _b Mn
having the composition of _d B _e Si _f. The subscript here is atomic%
And “a” is in the range of 68.0 to 70.0,
“B” ranges from 2.5 to 4.0 and “d” ranges from 1 to 4
And “e” is in the range of 10 to 12,
“F” is in the range of 14 to 15, and (Fe + Mn)
The ratio of / (Co + Fe + Mn) is 0.07 to 0.09. The vitreous alloy has a saturation magnetostriction value in the range of −1 × 10 ⁻⁶ to + 1 × 10 ⁻⁶ , a saturation magnetic induction of 0.65 to 0.80 Tesla, a Curie temperature in the range of 245 ° C. to 310 ° C., and 53
It has a primary crystallization temperature in the range of 0C to 575C. [0016] The purity of the composition is that of normal commercial practice. 2 at% (Si + B) can be replaced by carbon, aluminum or germanium without significantly degrading the desired magnetism of these alloys. Table 2 lists some magnetic and thermal properties of the vitreous alloys of the present invention with nearly zero magnetostriction. [0018] The presence of the metal element Mn increases T _cl and therefore increases the thermal stability of the alloy system. Mn contents above 4 atomic%, however, reduce the Curie temperature to levels below 245 ° C., which is undesirable in conventional magnetic devices. For some applications, the use of materials with micro + or micro-magnetostriction is desirable or acceptable. In that case, all the vitreous alloys in Table 2 exhibiting a saturation magnetostriction value in the range of -1 × 10 ^-6 to + 1 × 10 ^-6 are suitable. The magnetostriction value is (Fe + Mn) / (Co + Fe + Mn)
Is essentially determined by the ratio of These ratios are between 0.07 and 0.09. The vitreous alloys of the invention are conveniently prepared by other readily available techniques: for example, 197
U.S.A. was issued on November 5, 2014. S Patent 3,845,8
05 and December 24, 1974. 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, for a total of 24
A metalloid content of ~ 27 atomic% boron and silicon is sufficient for glass formation. [0022] Tables 3 and 4, various temperatures (T ₀₎ in annealed magnetostriction substantially 0 permeability of the magnetic induction of 50k Hz and 0.1 Tesla glassy alloys of the invention (mu), the excitation force (P ₈ ) shows ac iron loss (L). In summary, the glassy alloy of the present invention averaged L = 4 W / kg and P ₈ = 6 VA by water cooling after heat treatment shown in Table 3.
/ Kg, and μ = 28,000. Slow cooling after heat treatment generally results in high loss and exciting power and low magnetic permeability. However, when slowly cooled after heat treatment, the vitreous alloys of the present invention often exhibit results comparable to or better than those exhibited in the material that has been quenched after heat treatment. Table 5 shows examples of vitreous alloys outside the scope of the present invention. Alloys having excellent properties, as shown by the alloys of this invention, could not be obtained by prior art non-magnetostrictive vitreous alloys such as Co ₇₄ Fe ₆ B ₂₀ with high saturation magnetic induction. . This is because the Curie temperature is higher than the primary crystallization temperature, and heat treatment to improve properties, such as in low saturation magnetic induction, is not effective. The above properties achieved by the present invention may be obtained with prior art low magnetic induction vitreous alloys, but with Co _31.2 Fe _7.8 Ni
_Prior art alloys such as _39.0 B ₁₄ Si ₈ are susceptible to magnetic instability at relatively low temperatures, such as 150 ° C., as already mentioned. In the prior art, the best properties of the alloy are Co _67.4 Fe
_4.1 Ni _3.0 Mo _1.5 B _12.5 Si _11.5 L = 4 Obtained in Vitreous Alloy Quenched After Annealing at 380 ° C. for 15 Minutes
W / kg, P ₈ = 7 VA / kg and μ = 23,000. It is clear that the vitreous alloys of the present invention are generally superior to this class of vitreous alloys. [0024] In Table 5 a, b, c, d , at least one of e and f is outside the range of composition is limited in the invention Co _a Fe _b N
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 indicate that either the Curie temperature or saturation magnetic induction is too low to be practical in many magnetic applications. . The following example is provided to provide a more complete understanding of the present invention. Specific techniques, conditions, materials, ratios and reported data are provided to illustrate the principles,
The practice of the invention serves as an example and should not be construed as limiting the scope of the invention. Example 1 The glassy alloys listed in Sample Preparation Tables 2 to 5 are U.S.A. S Patent 3,85
The melt was quenched (approximately 10 ⁶ K / sec) according to the technique taught by 6,513 Chain and Pork. The resulting ribbon, typically 25-30 μm thick and 0.5-2.5 cm wide, was determined to lack effective crystallinity by X-ray diffraction (using CuK radiation) and scanning calorimetry. . The vitreous alloy ribbon was strong, shiny, hard and ductile. 2. A continuous ribbon of a vitreous alloy prepared according to the procedure described in Magnetic Measurement Example 1 was closed to a closed magnet path.
-Path) to form a bobbin (3.
8 cmO. D. ) Each sample contained 1-3 g of ribbon. Insulated primary and secondary windings (counting at least 10 each) were applied in an annular fashion. These samples were tested using commercial curve tracers for initial permeability and hysteresis loops (coercivity and remanence) and iron loss (IEEE).
Standard 106-1972). The saturation magnetization M _s ' of each sample was measured using a commercial vibrating sample magnetometer (Princeton Applied Research Laboratory).
In this case, the ribbon has several small squares (almost 2
(mm × 2 mm). These are arbitrarily oriented around a standard direction, and their planes provide the applied magnetic field (0 to 0).
720 kA / m). Saturated 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. Initial or primary crystallization temperatures (T _cl ) were used to compare the thermal stability of various vitreous alloys of the present and prior art inventions. Magnetic stability is described in Journal of Applied Physics, Vol. 49, p. 6510
(1978) Reorientation kinetic 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 between two short lengths of ribbon (Eastman-910 cement). The ribbon axis and the gauge axis were parallel. Magnetostriction is
According to the equation λ = 2/3 [(Δl / l) − (Δl / l)], parallel (Δl / l) and perpendicular (Δl / l) to a flat magnetic field.
1) was determined as a function of the applied magnetic field from the length strain. Having described the invention in considerable detail, there is no need to strictly adhere to this detailed description, and all further changes and modifications within the scope of the invention, which are limited by the appended claims, will occur to those skilled in the art. Can be suggested.

Continuation of front page    (56) References JP-A-61-210134 (JP, A)                 JP-A-58-25449 (JP, A)

Claims (1)

(57) [Claims] Has the formula _{Co a Fe b Mn d B e} Si f, subscript wherein characters are atomic%, a is in the range of from 68.0 to 70.0, b is the 2.5-4.0 Range, d ranges from 1 to 4, e ranges from 10 to 12, and f ranges from 14 to 1.
5 and (Fe + Mn) / (Co + Fe +
Mn) is between 0.07 and 0.09, at least 70
% Is a vitreous alloy, -1 × 10 ^-6 to + 1 × 10 ^-6
A magnetic alloy having a Curie temperature in the range of 245C to 310C, a primary crystallization temperature in the range of 530C to 575C, and a saturation magnetic induction of 0.65 to 0.80 Tesla. 2. _{Co 68.2 Fe 3.8 Mn 1 B 12} Si magnetic alloy of claim 1 having a composition of _15. 3. _2. The magnetic alloy according to claim 1, having a composition of Co _67.7 Fe _3.3 Mn ₂ B ₁₂ Si ₁₅ . 4. 2. The magnetic alloy according to claim 1, having a composition of Co _70.0 Fe _4.0 Mn ₁ B ₁₀ Si ₁₅ . 5. _{Co 69.5 Fe 3.5 Mn 2 B 10} Si 15 magnetic alloy of claim 1 having a composition. 6. _{Co 69.0 Fe 3.0 Mn 3 B 10} Si 15 magnetic alloy of claim 1 having a composition. 7. _{Co 68.5 Fe 2.5 Mn 4 B 10} Si 15 magnetic alloy of claim 1 having a composition.