U.S. patent application number 16/809919 was filed with the patent office on 2020-09-17 for soft magnetic alloy and magnetic component.
This patent application is currently assigned to TDK CORPORATION. The applicant listed for this patent is TDK CORPORATION. Invention is credited to Hajime AMANO, Kensuke ARA.
Application Number | 20200291507 16/809919 |
Document ID | / |
Family ID | 1000004706542 |
Filed Date | 2020-09-17 |
United States Patent
Application |
20200291507 |
Kind Code |
A1 |
ARA; Kensuke ; et
al. |
September 17, 2020 |
SOFT MAGNETIC ALLOY AND MAGNETIC COMPONENT
Abstract
Provided is a soft magnetic alloy comprising a composition
formula
(Fe.sub.(1-(.alpha.+.beta.))X1.sub..alpha.X2.sub..beta.).sub.(1-(a+b+c+d+-
e+f))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f. X1 denotes at
least one selected from Co and Ni; X2 denotes at least one selected
from Cu, Mg, Al, Mn, Ag, Sn, Bi, O, N, S, and rare earth elements;
M denotes at least one selected from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta,
and W; 0.080.ltoreq.b.ltoreq.0.150, 0.ltoreq.c.ltoreq.0.060,
0.ltoreq.d.ltoreq.0.060, 0.ltoreq.e.ltoreq.0.030,
0.0030.ltoreq.f.ltoreq.0.080, 0.0030.ltoreq.a+f.ltoreq.0.080,
b+c.gtoreq.0.100, .alpha..gtoreq.0, .beta..gtoreq.0, and
0.ltoreq..alpha.+.beta..ltoreq.0.50 are satisfied; and the soft
magnetic alloy has Fe-based nanocrystals with a bcc structure.
Inventors: |
ARA; Kensuke; (Tokyo,
JP) ; AMANO; Hajime; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TDK CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
TDK CORPORATION
Tokyo
JP
|
Family ID: |
1000004706542 |
Appl. No.: |
16/809919 |
Filed: |
March 5, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 38/001 20130101;
C22C 38/06 20130101; C21D 8/12 20130101; C22C 38/04 20130101; C22C
38/002 20130101; C22C 38/18 20130101; C22C 38/14 20130101; C22C
38/007 20130101; C22C 2200/04 20130101; C22C 38/12 20130101; C22C
38/105 20130101; C22C 38/008 20130101; C22C 38/16 20130101 |
International
Class: |
C22C 38/10 20060101
C22C038/10; C22C 38/00 20060101 C22C038/00; C22C 38/04 20060101
C22C038/04; C22C 38/06 20060101 C22C038/06; C22C 38/12 20060101
C22C038/12; C22C 38/14 20060101 C22C038/14; C22C 38/16 20060101
C22C038/16; C22C 38/18 20060101 C22C038/18; C21D 8/12 20060101
C21D008/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2019 |
JP |
2019-043796 |
Claims
1. A soft magnetic alloy comprising a composition formula
(Fe.sub.(1-(.alpha.+.beta.))X1.sub..alpha.X2.sub..beta.).sub.(1-(a++b+c+d-
+e+f))M.sub..alpha.B.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f, wherein
X1 denotes at least one selected from the group consisting of Co
and Ni; X2 denotes at least one selected from the group consisting
of Cu, Mg, Al, Mn, Ag, Sn, Bi, O, N, S, and rare earth elements; M
denotes at least one selected from the group consisting of Ti, V,
Cr, Zr, Nb, Mo, Hf, Ta, and W; a, b, c, d, e, f, .alpha. and .beta.
satisfy the relationships of: 0.080.ltoreq.b.ltoreq.0.150,
0.ltoreq.c.ltoreq.0.060, 0.ltoreq.d.ltoreq.0.060,
0.ltoreq.e.ltoreq.0.030, 0.0030.ltoreq.f.ltoreq.0.080,
0.0030.ltoreq..alpha.+.beta..ltoreq.0.080, b+c.gtoreq.0.100,
.alpha..gtoreq.0, .beta..gtoreq.0, and
0.ltoreq..alpha.+.beta..ltoreq.0.50; and the soft magnetic alloy
has Fe-based nanocrystals with a bcc structure.
2. The soft magnetic alloy according to claim 1, satisfying the
relationships of: c.ltoreq.0.040, d.ltoreq.0.030,
0.010.ltoreq.f.ltoreq.0.050, and 0.010.ltoreq.a+f.ltoreq.0.050.
3. The soft magnetic alloy according to claim 1, wherein an
expansion value of a (110) plane spacing of the Fe-based
nanocrystal with respect to a (110) plane spacing of pure iron is
0.002 angstroms or less.
4. The soft magnetic alloy according to claim 2, wherein an
expansion value of a (110) plane spacing of the Fe-based
nanocrystal with respect to a (110) plane spacing of pure iron is
0.002 angstroms or less.
5. The soft magnetic alloy according to claim 1, wherein an average
grain size of the Fe-based nanocrystals is 5 nm or more and 30 nm
or less.
6. The soft magnetic alloy according to claim 1 having a ribbon
shape.
7. The soft magnetic alloy according to claim 1 having a powder
shape.
8. A magnetic component comprising the soft magnetic alloy
according to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a soft magnetic alloy and a
magnetic component.
[0002] In recent years, there is a demand for higher efficiency and
lower power consumption in electronic, information, and
communication equipment or the like. Furthermore, the above demand
is further strengthened for the realization of a low-carbon
society. Therefore, there is also a demand for improvement of power
supply efficiency and reduction of energy loss in a power supply
circuit for the electronic, information, and communication
equipment or the like. As a result, there is a demand for
improvement of saturation magnetic flux density and reduction of
core loss (magnetic core loss) in a magnetic core included in a
magnetic component used in the power supply circuit. If the core
loss is reduced, the energy loss of the power supply circuit
decreases, and high efficiency and energy saving of the electronic,
information, and communication equipment or the like can be
achieved.
[0003] As one of the methods for reducing the core loss, it is
effective to constitute the magnetic core with a magnetic material
having high soft magnetic properties. For example, in Patent
Document 1, a Fe--B-M soft magnetic alloy is disclosed. M denotes
at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Mo, and
W. [0004] Patent Document 1: Japanese Patent Laid-Open No.
7-268566
[0005] Patent Document 1 describes that the soft magnetic
properties and the saturation magnetic flux density of the soft
magnetic alloy can be improved by performing a heat treatment on an
amorphous metal produced by liquid phase cooling to deposit fine
crystalline phase. However, it is necessary to reduce coercivity in
order to improve the soft magnetic properties of the soft magnetic
alloy, but reduction in the coercivity has not been sufficiently
considered in Patent Document 1.
[0006] The coercivity is mainly derived from magnetocrystalline
anisotropy and magnetoelastic effect. The coercivity derived from
the magnetoelastic effect appears when stress is applied to a
magnetic material having a large magnetostriction. The coercivity
derived from the magnetocrystalline anisotropy can be reduced by
isotropically depositing nanometer scale fine Fe-based crystal
phase.
[0007] However, it is also necessary to reduce the magnetostriction
in order to sufficiently reduce the coercivity derived from the
magnetoelastic effect. In addition, in a composition region in
which the content ratio of M is relatively small and the content
ratio of B and P having a role of enhancing an amorphous forming
ability is relatively large, an amorphous state before the heat
treatment is uniform and thus fine crystals after the heat
treatment are also easy to become uniform. Therefore, it is
advantageous for suppressing the magnetocrystalline anisotropy, and
a high saturation magnetic flux density is obtained. However, on
the other hand, the magnetostriction tends to increase. As a
result, there is a problem that, during the manufacturing of the
magnetic component, the property deterioration due to the residual
stress caused by the magnetostriction becomes remarkable.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention has been made in view of the above
circumstances, and an objective thereof is to provide a soft
magnetic alloy capable of achieving both low coercivity and high
saturation magnetic flux density by reducing both the
magnetostriction and the magnetocrystalline anisotropy.
[0009] Aspects of the present invention includes: [0010] [1] A soft
magnetic alloy comprising a composition formula
[0010]
(Fe.sub.(1-(.alpha.+.beta.))X1.sub..alpha.X2.sub..beta.).sub.(1-a-
+b+c+d+e+f))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f, [0011]
wherein X1 denotes at least one selected from the group consisting
of Co and Ni; [0012] X2 denotes at least one selected from the
group consisting of Cu, Mg, Al, Mn, Ag, Sn, Bi, O, N, S, and rare
earth elements; [0013] M denotes at least one selected from the
group consisting of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W; [0014] a,
b, c, d, e, f, .alpha. and .beta. satisfy the relationships of:
[0014] 0.080.ltoreq.b.ltoreq.0.150,
0.ltoreq.c.ltoreq.0.060,
0.ltoreq.d.ltoreq.0.060,
0.ltoreq.e.ltoreq.0.030,
0.0030.ltoreq.f.ltoreq.0.080,
0.0030.ltoreq.a+f.ltoreq.0.080,
b+c.gtoreq.0.100,
a.gtoreq.0,
.beta..gtoreq.0, and
0.ltoreq..alpha.+.beta..ltoreq.0.50; and [0015] the soft magnetic
alloy has Fe-based nanocrystals with a bcc structure.
[0016] [2] The soft magnetic alloy according to [1], satisfying the
relationships of:
c.ltoreq.0.040,
d.ltoreq.0.030,
0.010.ltoreq.f.ltoreq.0.050, and
0.010.ltoreq.a+f.ltoreq.0.050.
[0017] [3] The soft magnetic alloy according to [1] or [2], wherein
an expansion value of a (110) plane spacing of the Fe-based
nanocrystal with respect to a (110) plane spacing of pure iron is
0.002 angstroms or less.
[0018] [4] The soft magnetic alloy according to any one of [1] to
[3], wherein an average grain size of the Fe-based nanocrystal is 5
nm or more and 30 nm or less.
[0019] [5] The soft magnetic alloy according to any one of [1] to
[4] having a ribbon shape.
[0020] [6] The soft magnetic alloy according to any one of [1] to
[4] having a powder shape.
[0021] [7] A magnetic component comprising the soft magnetic alloy
according to any one of [1] to [4].
[0022] According to the present invention, it is possible to
provide a soft magnetic alloy capable of achieving both low
coercivity and high saturation magnetic flux density.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Hereinafter, the present invention is described in detail in
the following order. [0024] 1. Soft magnetic alloy [0025] 2.
Manufacturing method for soft magnetic alloy [0026] 3. Magnetic
component
[0027] (1. Soft Magnetic Alloy)
[0028] The soft magnetic alloy of the present embodiment has
Fe-based nanocrystals and amorphous. The Fe-based nanocrystal is a
crystal of which the crystal grain size is in the nanometer scale
and which has a bcc (body-centered cubic lattice) structure. In the
soft magnetic alloy, many Fe-based nanocrystals are deposited and
dispersed in the amorphous. A soft magnetic alloy in which the
Fe-based nanocrystals are dispersed in the amorphous is easy to
exhibit high saturation magnetic flux density and low
coercivity.
[0029] In the present embodiment, the average crystal grain size of
the Fe-based nanocrystal is preferably 5 nm or more and 30 nm or
less. With the average crystal grain size in the above range, it is
easy to achieve low magnetostriction, high saturation magnetic flux
density, and low coercivity.
[0030] Subsequently, the composition of the soft magnetic alloy of
the present embodiment is described in detail.
[0031] The composition of the soft magnetic alloy of the present
embodiment is represented by a composition formula
(Fe.sub.(1-(.alpha.+.beta.))X1.sub..alpha.X2.sub..beta.).sub.(1-(a+b+c+d+-
e+f))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f.
[0032] In the above composition formula, M denotes at least one
element selected from the group consisting of Ti, V, Cr, Zr, Nb,
Mo, Hf, Ta, and W.
[0033] In addition, "a" represents the content ratio of M. In the
present embodiment, "a" is determined by the relationship with "f"
(described later) representing the content ratio of Zn.
[0034] In the above composition formula, "b" represents the content
ratio of B (boron), and "b" satisfies 0.080<b<0.150. The
content ratio (b) of B is preferably 0.130 or less.
[0035] In the above composition formula, "c" represents the content
ratio of P (phosphorus), and "c" satisfies 0<c<0.060. That
is, P is an optional component. The content ratio (c) of P is
preferably 0.005 or more, and more preferably 0.010 or more. In
addition, the content ratio (c) of P is preferably 0.040 or
less.
[0036] In the present embodiment, the sum of the content ratios of
B and P satisfies b+c.gtoreq.0.100.
[0037] When "c" is within the above range, the coercivity tends to
decrease. When "c" is too small, the above effects tend to be
hardly obtained. On the other hand, when "c" is too large, the
crystal grain size after the heat treatment tends to increase, and
thus the coercivity tends to increase. When b+c is within the above
range, homogeneity of amorphous phase during liquid phase quenching
becomes high, uniform fine crystals can be obtained after the heat
treatment, and thus the coercivity tends to decrease.
[0038] In the composition region in which the content ratios of B
and P are relatively large and M is contained in a predetermined
ratio, a structure is obtained in which the amorphous forming
ability during liquid phase cooling of a raw material alloy is high
and fine nanocrystals are deposited after the heat treatment of the
alloy obtained by cooling. As a result, a soft magnetic alloy with
suppressed magnetocrystalline anisotropy is obtained easily. In
addition, high saturation magnetic flux density is obtained easily
in a region in which the content ratio of M is relatively
small.
[0039] However, the soft magnetic alloy having the above
composition region tends to have large positive magnetostriction.
As described above, the coercivity is affected by not only the
magnetocrystalline anisotropy but also the magnetoelastic effect.
If the magnetoelastic effect is great, that is, when the
magnetostriction is large, the coercivity may not be sufficiently
reduced.
[0040] Thus, in the present embodiment, a predetermined amount of
Zn (zinc) is contained in the soft magnetic alloy. In this way, it
is possible to reduce the positive magnetostriction of the soft
magnetic alloy while maintaining the structure having fine
nanocrystals and the high saturation magnetic flux density. In
other words, the soft magnetic alloy of the present embodiment
exhibits small coercivity and high saturation magnetic flux
density, because both the magnetocrystalline anisotropy and the
magnetoelastic effect are reduced.
[0041] Specifically, in the above composition formula, "f"
represents the content ratio of Zn, and "f" satisfies
0.003.ltoreq.f.ltoreq.0.080, and "a" and "f" satisfy
0.003.ltoreq.a+f.ltoreq.0.080. That is, in the present embodiment,
M is substituted with Zn (zinc). Zn may substitute all of M, or may
substitute a part of M within the above range.
[0042] When "f" is too small, the magnetostriction reduction effect
is small. As a result, the coercivity may not be reduced. On the
other hand, when "f" is too large, the saturation magnetic flux
density tends to decrease easily and the magnetostriction tends to
increase.
[0043] In the present embodiment, "f" is preferably 0.010 or more.
On the other hand, "f" is preferably 0.050 or less. In addition,
a+f is preferably 0.010 or more. On the other hand, a+f is
preferably 0.050 or less.
[0044] A mechanism in which the magnetostriction can be reduced by
substituting M with Zn is not clear, but it can be inferred, for
example, as follows.
[0045] One of the factors for the increase in magnetostriction is
the expansion in the lattice spacing of bcc caused by
solid-solution of M in the Fe-based nanocrystals having a bcc
structure. Because Zn has an atomic radius smaller than that of the
M element, the expansion of the lattice spacing of bcc can be
suppressed when Zn, instead of M, is solid-soluted in the Fe-based
nanocrystals. As a result, the positive magnetostriction of the
Fe-based nanocrystals is considered to decrease. In addition, the
lattice spacing tends to expand when Zn is added excessively, and
as a result, the magnetostriction reduction effect is considered to
decreases.
[0046] In addition to the above, because negative magnetostriction
of the bcc structure is considered to increase when Zn is
solid-soluted in the Fe-based nanocrystals, the positive
magnetostriction of the Fe-based nanocrystals is considered to
decrease thereby.
[0047] Moreover, similar to M, Zn also has the effect of refinement
of the Fe-based nanocrystals, and thus it is possible to obtain a
soft magnetic alloy of which the magnetostriction is reduced while
the structure having fine nanocrystals is maintained.
[0048] In addition, it is preferable to suppress the solid-solution
of M in bcc regardless of the presence or absence of the
solid-solution of Zn in bcc. As described above, the lattice
spacing of bcc expands when M is solid-soluted in bcc, and thus the
expansion in the lattice spacing of bcc is preferably equal to or
less than a predetermined value.
[0049] In the present embodiment, a (110) plane spacing of bcc is
employed as the lattice spacing of bcc. Because pure iron does not
contain M, M is not solid-soluted in bcc of pure iron. That is, the
expansion in the plane spacing caused by the solid-solution of M in
bcc does not occur. Accordingly, it means that the closer the (110)
plane spacing of the soft magnetic alloy is to the (110) plane
spacing of the pure iron, the lower the solid-solution ratio of M
in bcc is.
[0050] In the present embodiment, a value obtained by subtracting
the (110) plane spacing of pure iron from the (110) plane spacing
of the soft magnetic alloy is defined as an expansion value of the
(110) plane spacing. The expansion value of the (110) plane spacing
is preferably 0.002 angstroms or less.
[0051] With the expansion value of the (110) plane spacing in the
above range, the magnetostriction of the soft magnetic alloy can be
reduced.
[0052] The (110) plane spacing of the soft magnetic alloy and the
(110) plane spacing of pure iron can be calculated by XRD (X-Ray
Diffraction) measurement. That is, the (110) plane spacing can be
calculated from the angle at which a diffraction peak of the (110)
plane is observed and the wavelength of X-ray. Then, the expansion
value of the (110) plane spacing may be calculated based on the
calculated spacing.
[0053] Note that, in order to reduce the influence of the inherent
error of the XRD measurement device, the (110) plane spacing of the
soft magnetic alloy and the (110) plane spacing of pure iron are
preferably measured with the same device and under the same
measurement conditions.
[0054] In the above composition formula, "d" represents the content
ratio of Si (silicon), and "d" satisfies 0<d<0.060. That is,
Si is an optional component. The content ratio (d) of Si is
preferably 0.001 or more, and more preferably 0.005 or more. In
addition, the content ratio (d) of Si is preferably 0.030 or
less.
[0055] When "d" is within the above range, there is a tendency that
the resistivity of the soft magnetic alloy is particularly easy to
be improved, and the coercivity is reduced easily. On the other
hand, when "d" is too large, the coercivity of the soft magnetic
alloy tends to increase.
[0056] In the above composition formula, "e" represents the content
ratio of C (carbon), and "e" satisfies 0<e<0.030. That is, C
is an optional component. The content ratio (e) of C is preferably
0.001 or more. In addition, the content ratio (e) of C is
preferably 0.015 or less.
[0057] When "e" is within the above range, there is a tendency that
the coercivity of the soft magnetic alloy is particularly easy to
be reduced. When "e" is too large, the crystal grain size tends to
increase and the coercivity tends to increase.
[0058] In the above composition formula, 1-(a+b+c+d+e+f) represents
the total content ratio of Fe (iron), X1 and X2. The total content
ratio of Fe, X1 and X2 is not particularly limited as long as "a",
"b", "c", "d", "e" and "f" are within the above ranges. In the
present embodiment, the total content ratio (1-(a+b+c+d+e+f)) is
preferably 0.73 or more and 0.95 or less. With the total content
ratio set to 0.73 or more, high saturation magnetic flux density is
obtained easily. In addition, with the total content ratio set to
0.95 or less, crystal phase configured by crystals having a grain
size larger than 30 nm is hardly generated. As a result, a soft
magnetic alloy in which the Fe-based nanocrystals are deposited by
heat treatment tends to be obtained easily.
[0059] X1 denotes at least one element selected from the group
consisting of Co and Ni. In the above composition formula, "a"
represents the content ratio of X1, and ".alpha." is 0 or more in
the present embodiment. That is, X1 is an optional component.
[0060] In addition, when the total number of atoms of the
composition is set to 100 at %, the number of atoms of X1 is
preferably 40 at % or less. That is, it is preferable to satisfy
0.ltoreq.a {1-(a+b+c+d+e+f)}.ltoreq.0.40.
[0061] X2 denotes at least one element selected from the group
consisting of Cu, Mg, Al, Mn, Ag, Sn, Bi, O, N, S, and rare earth
elements. In the above composition formula, "0" represents the
content ratio of X2, and ".beta." is 0 or more in the present
embodiment. That is, X2 is an optional component.
[0062] In addition, when the total number of atoms of the
composition is set to 100 at %, the number of atoms of X2 is
preferably 3.0 at % or less. That is, it is preferable to satisfy
0.ltoreq..beta.{1-(a+b+c+d+e+f)}.ltoreq.0.030.
[0063] Furthermore, the range (substitution ratio) in which X1
and/or X2 substitutes for Fe is set equal to or less than half of
the total number of Fe atoms in terms of the number of atoms. That
is, 0.ltoreq..alpha.+.beta..ltoreq.0.50 is satisfied. When
.alpha.+.beta. is too large, it tends to be difficult to obtain a
soft magnetic alloy in which the Fe-based nanocrystals are
deposited by heat treatment.
[0064] Note that, the soft magnetic alloy of the present embodiment
may include elements other than the above elements as inevitable
impurities. For example, the elements other than the above elements
may be included in a total of 0.1% by mass or less with respect to
100% by mass of the soft magnetic alloy.
[0065] (2. Manufacturing Method of Soft Magnetic Alloy)
[0066] Subsequently, a method for manufacturing the soft magnetic
alloy is described. The soft magnetic alloy of the present
embodiment is manufactured by, for example, depositing Fe-based
nanocrystals in an amorphous alloy having the above
composition.
[0067] As the method for obtaining the amorphous alloy, for
example, a method of quenching a molten metal to obtain an
amorphous alloy is exemplified. In the present embodiment, a ribbon
or flake of the amorphous alloy may be obtained by a single roll
method, or powder of the amorphous alloy may be obtained by an
atomization method. Hereinafter, a method of obtaining the
amorphous alloy by the single roll method and a method of obtaining
the amorphous alloy by a gas atomization method as an example of
the atomization method are described.
[0068] In the single roll method, first, a raw material (pure metal
or the like) of each metal element contained in the soft magnetic
alloy is prepared and is weighed so as to obtain a composition of
the finally obtained soft magnetic alloy, and the raw material is
melted to obtain molten metal. Note that, the method for melting
the raw material of the metal elements is not particularly limited;
for example, a method of melting the material by high-frequency
heating in a predetermined atmosphere is exemplified. The
temperature of the molten metal may be determined in consideration
of the melting point of each metal element and may be, for example,
1200-1500.degree. C.
[0069] Next, for example, inside a chamber filled with an inert
gas, the molten metal is injected and supplied from a nozzle to a
cooled rotary roll, and thereby a ribbon-shaped or flaky amorphous
alloy is manufactured toward the rotating direction of the rotary
roll. Examples of the material of the rotary roll include copper.
The temperature of the rotary roll, the rotating speed of the
rotary roll, the atmosphere inside the chamber, and the like may be
determined corresponding to the conditions under which the Fe-based
nanocrystals are easily deposited in the amorphous during the heat
treatment described later.
[0070] In the gas atomization method, similar to the single roll
method, first, molten metal is obtained in which the raw material
of the soft magnetic alloy is melted. The temperature of the molten
metal may be determined in consideration of the melting point of
each metal element as in the case of the single roll method, and
may be, for example, 1200-1500.degree. C.
[0071] The obtained molten metal is supplied into the chamber as a
linear continuous fluid through a nozzle provided at the bottom of
the crucible, and a high-pressure gas is sprayed onto the supplied
molten metal to make the molten metal into droplets, and the
droplets are quenched to obtain a powder-shaped amorphous alloy.
The gas injection temperature, the pressure in the chamber, and the
like may be determined corresponding to the conditions under which
the Fe-based nanocrystals are easily deposited in the amorphous
during the heat treatment described later. In addition, the
particle size can be adjusted by sieving classification, airflow
classification, or the like.
[0072] The ribbon and powder obtained by the above methods are
configured by an amorphous alloy. The amorphous alloy may be an
amorphous alloy in which fine crystals are dispersed in an
amorphous, or may be an alloy not containing crystals.
[0073] Next, the obtained ribbon and powder are subjected to a heat
treatment (first heat treatment). By performing the first heat
treatment, diffusion of the elements constituting the soft magnetic
alloy can be promoted, a thermodynamic equilibrium state can be
achieved in a short time, and strain or stress existing in the soft
magnetic alloy can be removed. As a result, it becomes easy to
obtain a soft magnetic alloy in which the Fe-based nanocrystals are
deposited.
[0074] In the present embodiment, the condition of the first heat
treatment is not particularly limited as long as the Fe-based
nanocrystals are easily deposited under this condition. In the case
of ribbon, for example, the heat treatment temperature can be set
to 400-700.degree. C., and the holding time can be set to 0.5-10
hours.
[0075] In the present embodiment, it is preferable to further
perform a heat treatment (second heat treatment) after the first
heat treatment. By performing the second heat treatment, M
solid-soluted in the Fe-based nanocrystals can be released out of
the crystals. In the case of a composition containing a relatively
large amount of Zn, excessively solid-soluted Zn can be released
out of the crystals and the amount of solid-solution Zn in the
crystals can be optimized. As a result, the (110) plane spacing of
the Fe-based nanocrystal decreases and gets close to the (110)
plane spacing of pure iron, and thus the magnetostriction can be
reduced.
[0076] The heat treatment temperature of the second heat treatment
is preferably lower than the heat treatment temperature of the
first heat treatment, and more preferably lower by 50.degree. C. or
more. In addition, the holding time of the second heat treatment is
preferably three hours or longer and ten hours or shorter.
[0077] After the above heat treatment, the soft magnetic alloy of
the present embodiment having a ribbon shape or the soft magnetic
alloy of the present embodiment having a powder shape is
obtained.
[0078] In addition, there is no particular limitation on the
calculation method of the average grain size of the Fe-based
nanocrystals contained in the soft magnetic alloy obtained by the
heat treatment. For example, the calculation can be made by a
transmission electron microscope observation. In addition, there is
no particular limitation on a method for confirming that the
crystal structure is a bcc (body-centered cubic lattice) structure.
For example, the confirmation can be made using X-ray diffraction
measurement.
[0079] (3. Magnetic Component)
[0080] The magnetic component of the present embodiment is not
particularly limited as long as this magnetic component includes
the above soft magnetic alloy as a magnetic material. For example,
the magnetic component may have a magnetic core configured by the
above soft magnetic alloy.
[0081] Examples of the method for obtaining a magnetic core from
the ribbon-shaped soft magnetic alloy include a method of winding
the ribbon-shaped soft magnetic alloy or a method of laminating the
ribbon-shaped soft magnetic alloy. When the ribbon-shaped soft
magnetic alloy is laminated via an insulator during the lamination,
a magnetic core with further improved properties can be
obtained.
[0082] Examples of the method for obtaining a magnetic core from
the powder-shaped soft magnetic alloy include a method in which the
powder-shaped soft magnetic alloy is appropriately mixed with a
binder and then molded using a press mold. In addition, by applying
an oxidation treatment, an insulating coating or the like on the
powder surface before the mixture with the binder, the magnetic
core has an improved resistivity and is adapted to higher frequency
regions.
[0083] The magnetic component of the present embodiment is suitable
for a power inductor used in a power supply circuit. In addition,
applications of the magnetic core include, in addition to the
inductor, a transformer, a motor, and the like.
[0084] The present embodiment of the present invention has been
described above, but the present invention is not limited to the
above embodiment and may be modified in various aspects within the
scope of the present invention.
EXAMPLES
[0085] Hereinafter, the present invention is described in more
detail with reference to examples, but the present invention is not
limited to these examples.
Examples 1-21 and Comparative Examples 1-10
[0086] First, raw metal of the soft magnetic alloy was prepared.
The prepared raw metal was weighed so as to satisfy the composition
shown in Table 1 and was melted by high-frequency heating to
prepare a mother alloy.
[0087] Then, the prepared mother alloy was heated and melted to
obtain molten metal having a melting temperature of 1250.degree. C.
The molten metal was sprayed on a rotary roll by a single roll
method to form a ribbon. Note that, the material of the rotary roll
was Cu. In addition, the standard rotating speed of the rotary roll
was 25 m/sec. By adjusting the roll rotating speed, the thickness
of the obtained ribbon was set to 20 .mu.m-30 .mu.m, the width of
the ribbon was set to 4 mm-5 mm, and the length of the ribbon was
set to tens of meters.
[0088] As a result of performing X-ray diffraction measurement on
each of the obtained ribbons, in all the examples, the ribbon had
an amorphous or a nanohetero-structure in which initial fine
crystals exist in the amorphous.
[0089] Then, the ribbons of Examples 1-21 and Comparative Examples
1-10 were subjected to heat treatment at a heat treatment
temperature of 550.degree. C. and for a holding time of one hour.
As a result of the X-ray diffraction measurement and the
transmission electron microscope observation performed on the
ribbon after the heat treatment, in all the examples, it was
confirmed that the ribbon after the heat treatment had Fe-based
nanocrystals of which the crystal structure was bcc and the average
crystal grain size of the Fe-based nanocrystals was 5-30 nm. In
addition, it was confirmed by ICP analysis that there was no change
in the alloy composition before and after the heat treatment.
[0090] The magnetostriction, saturation magnetic flux density, and
coercivity were measured for each ribbon after the heat treatment.
The magnetostriction was measured by a strain gauge method. The
saturation magnetic flux density (Bs) was measured using a
vibrating sample magnetometer (VSM) at a magnetic field of 1000
kA/m. The coercivity (Hc) was measured using a direct current BH
tracer at a magnetic field of 5 kA/m.
[0091] Regarding the magnetostriction, a sample in which the
absolute value of magnetostriction is 2.50 ppm or less was judged
to be good. A sample in which the absolute value of
magnetostriction is 1.50 ppm or less is more preferable. Regarding
the saturation magnetic flux density, a sample in which the
saturation magnetic flux density was 1.40 T or more was judged to
be good. A sample in which the saturation magnetic flux density is
1.60 T or more was more preferable. Regarding the coercivity, a
sample in which the coercivity is 2.0 A/m or less was judged to be
good. A sample in which the coercivity is 1.5 A/m or less is more
preferable. The results are shown in Table 1.
[0092] The value of the coercivity measured as described above
includes both a component derived from the magnetocrystalline
anisotropy and a component derived from the magnetoelastic effect
caused by the magnetostriction. The component derived from the
magnetoelastic effect is the product of the magnetostriction and
the stress and thus cannot be detected as coercivity when the
internal stress is not applied to the sample. Accordingly, it is
necessary to confirm that both the coercivity and the
magnetostriction show a low value and the saturation magnetic flux
density shows a high value, in order to determine whether the
effect of the present invention exists.
[0093] In view of the situation described above, in Table 1 and
Tables 2-4 described later, as shown below, scores corresponding to
the measured property values were allocated to each sample, and the
superiority of the samples was comprehensively evaluated according
to the numerical value of the product of the scores. The results
are shown in a column of comprehensive evaluation.
[0094] With respect to each sample, zero point was allocated when
the magnetostriction is greater than 2.50 ppm, one point was
allocated when the magnetostriction is greater than 1.50 ppm and
equal to or lower than 2.50 ppm, and two points were allocated when
the magnetostriction is 1.50 ppm or less. With respect to each
sample, zero point was allocated when the saturation magnetic flux
density is less than 1.40 T, one point was allocated when the
saturation magnetic flux density is 1.40 T or more and less than
1.60 T, and two points were allocated when the saturation magnetic
flux density is 1.60 T or more. With respect to each sample, zero
point was allocated when the coercivity is greater than 2.0 A/m,
one point was allocated when the coercivity is greater than 1.5 A/m
and equal to or lower than 2.0 A/m, and two points were allocated
when the coercivity is 1.5 A/m or less. Then, the product of the
allocated numerical values was calculated and a sample in which the
numerical value of the product was equal to or greater than 1 was
judged to be good.
TABLE-US-00001 TABLE 1 Soft magnetic alloy Property
Fe.sub.(1-a-b-c-d-e-f)M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f.quadra-
ture..alpha. Saturation = .beta. = 0 Magneto- magnetic flux Coer-
Fe striction density civity Compre- 1 - a - b - c - B P Si C M Zn
.lamda. Bs Hc hensive d - e - f b c d e Element a f a + f b + c
(.times.10.sup.-6) (T) (A/m) evaluation Example 1 0.830 0.120 0.000
0.000 0.000 -- 0.000 0.050 0.050 0.120 1.13 1.63 1.7 4 Example 2
0.850 0.120 0.000 0.000 0.000 -- 0.000 0.030 0.030 0.120 0.63 1.72
1.5 8 Example 3 0.860 0.130 0.000 0.000 0.000 -- 0.000 0.010 0.010
0.130 0.97 1.74 1.8 4 Example 4 0.830 0.120 0.000 0.000 0.000 Nb
0.020 0.030 0.050 0.120 1.40 1.65 1.0 8 Example 5 0.850 0.120 0.000
0.000 0.000 Nb 0.010 0.020 0.030 0.120 0.85 1.70 1.2 8 Example 6
0.847 0.150 0.000 0.000 0.000 -- 0.000 0.003 0.003 0.150 2.39 1.63
1.8 2 Example 7 0.820 0.100 0.000 0.000 0.000 -- 0.000 0.080 0.080
0.100 1.72 1.48 1.7 1 Example 8 0.820 0.100 0.000 0.000 0.000 Nb
0.040 0.040 0.080 0.100 1.59 1.43 1.3 2 Example 9 0.840 0.090 0.040
0.000 0.000 -- 0.000 0.030 0.030 0.130 0.89 1.65 1.3 8 Example 10
0.830 0.080 0.060 0.000 0.000 -- 0.000 0.030 0.030 0.140 2.33 1.55
1.1 2 Example 11 0.840 0.100 0.000 0.030 0.000 -- 0.000 0.030 0.030
0.100 1.46 1.70 1.3 8 Example 12 0.810 0.100 0.000 0.060 0.000 --
0.000 0.030 0.030 0.100 2.43 1.57 1.1 2 Example 13 0.840 0.100
0.000 0.000 0.030 -- 0.000 0.030 0.030 0.100 1.05 1.71 1.3 8
Example 14 0.830 0.120 0.000 0.000 0.000 Ti 0.020 0.030 0.050 0.120
1.41 1.64 1.5 8 Example 15 0.830 0.120 0.000 0.000 0.000 V 0.020
0.030 0.050 0.120 1.47 1.62 1.3 8 Example 16 0.830 0.120 0.000
0.000 0.000 Cr 0.020 0.030 0.050 0.120 1.99 1.62 1.5 4 Example 17
0.830 0.120 0.000 0.000 0.000 Zr 0.020 0.030 0.050 0.120 1.39 1.60
0.8 8 Example 18 0.830 0.120 0.000 0.000 0.000 Mo 0.020 0.030 0.050
0.120 1.80 1.60 1.2 4 Example 19 0.830 0.120 0.000 0.000 0.000 Hf
0.020 0.030 0.050 0.120 1.74 1.61 0.8 4 Example 20 0.830 0.120
0.000 0.000 0.000 Ta 0.020 0.030 0.050 0.120 1.68 1.60 1.0 4
Example 21 0.830 0.120 0.000 0.000 0.000 W 0.020 0.030 0.050 0.120
1.55 1.63 1.3 4 Comparative 0.820 0.100 0.000 0.000 0.000 Nb 0.080
0.000 0.080 0.100 2.78 1.38 0.7 0 Example 1 Comparative 0.830 0.120
0.000 0.000 0.000 Nb 0.050 0.000 0.050 0.120 8.01 1.55 1.4 0
Example 2 Comparative 0.850 0.120 0.000 0.000 0.000 Nb 0.030 0.000
0.030 0.120 4.61 1.66 1.7 0 Example 3 Comparative 0.860 0.130 0.000
0.000 0.000 Nb 0.010 0.000 0.010 0.130 2.65 1.71 1.9 0 Example 4
Comparative 0.790 0.120 0.000 0.000 0.000 -- 0.000 0.090 0.090
0.120 3.88 1.32 2.4 0 Example 5 Comparative 0.848 0.150 0.000 0.000
0.000 -- 0.000 0.002 0.002 0.150 2.82 1.65 4.5 0 Example 6
Comparative 0.790 0.120 0.000 0.000 0.000 Nb 0.050 0.040 0.090
0.120 5.32 1.45 1.4 0 Example 7 Comparative 0.880 0.090 0.000 0.000
0.000 -- 0.000 0.030 0.030 0.090 0.60 1.68 135 0 Example 8
Comparative 0.810 0.160 0.000 0.000 0.000 -- 0.000 0.030 0.030
0.160 4.03 1.61 78 0 Example 9 Comparative 0.870 0.070 0.030 0.000
0.000 -- 0.000 0.030 0.030 0.100 0.70 1.64 23 0 Example 10
[0095] From Table 1, it was confirmed that the numerical value of
the product is equal to or greater than 1 when the content ratios
of boron and zinc, the total content ratio of M and zinc, and the
total content ratio of boron and phosphorus are within the
above-described range. In particular, it was confirmed that the
numerical value of the product is equal to or greater than 4 and
particularly good properties are obtained when the content ratio of
zinc, the total content ratio of M and zinc, the content ratio of
phosphorus, and the content ratio of silicon are within the
preferable range described above.
[0096] On the contrary, it was confirmed that when zinc is not
contained (Comparative Examples 1-4), the magnetostriction is large
and the above effect is not obtained even if the other content
ratios are within the above ranges. In addition, it was confirmed
that when the content ratio of zinc is too large (Comparative
Example 5) and too small (Comparative Example 6), the
magnetostriction is also large and the above effect is not obtained
either.
[0097] In addition, it was confirmed that when the total content
ratio of M and zinc is too large (Comparative Example 7), the
magnetostriction is large and the above effect is not obtained.
[0098] Furthermore, it was confirmed that when the sum of the
content ratios of boron and phosphorus (b+c) is too small
(Comparative Example 8) and when the content ratio of boron is too
small even if b+c is within the above range (Comparative Example
10), the coarse grain growth of initial fine crystals occurs during
the heat treatment and thus the coercivity increases. In addition,
it was confirmed that when the content ratio of boron is too large
(Comparative Example 9), the magnetostriction increases and the
coercivity increases due to the generation of an iron-boron
compound such as Fe.sub.3B or the like.
Examples 22-34
[0099] Except that the "X1" and "X2" elements in the composition
formula and the content ratios in the sample of Example 4 were set
to the elements and the content ratios shown in Table 2, the soft
magnetic alloy was produced in the same manner as in Example 4, and
the same evaluation as in Example 4 was performed. The results are
shown in Table 2.
TABLE-US-00002 TABLE 2 Property Soft magnetic alloy Saturation
(Fe.sub.(1-.alpha.-.beta.)X1.sub..alpha.X2.sub..beta.).sub.(1-a-b-c-d-e-f-
)M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eZn.sub.f Magneto- magnetic
flux Coer- X1 X2 striction density civity Compre- .alpha. (1 - a -
b - c - .beta. (1 - .alpha. - b - c - .lamda. Bs Hc hensive element
d - e - f) element d - e - f) (.times.10.sup.-6) (T) (A/m)
evaluation Example 22 Co 0.1 -- -- 1.42 1.69 1.7 4 Example 23 Co
0.4 -- -- 1.48 1.74 1.9 4 Example 24 Ni 0.1 -- -- 1.69 1.66 1.5 4
Example 25 Ni 0.4 -- -- 2.28 1.56 1.5 4 Example 26 -- -- Cu 0.008
1.37 1.72 1.7 4 Example 27 -- -- Mg 0.03 1.33 1.66 1.7 4 Example 28
-- -- Al 0.03 1.48 1.65 1.8 4 Example 29 -- -- Mn 0.03 1.49 1.58
1.5 4 Example 30 -- -- Ag 0.012 1.55 1.67 1.4 4 Example 31 -- -- Sn
0.03 1.22 1.62 1.5 8 Example 32 -- -- Bi 0.03 1.40 1.61 1.6 4
Example 33 -- -- Y 0.03 1.43 1.59 1.4 4 Example 34 -- -- La 0.03
1.44 1.52 1.3 4
[0100] From Table 2, it was confirmed that good properties are
obtained even when the element and the content ratios of the X1
element and the X2 element are changed.
Examples 35-38
[0101] Except that the heat treatment (second heat treatment) was
performed under the conditions shown in Table 3 after the heat
treatment (first heat treatment) performed at 550.degree. C. for
one hour for the sample of Example 8, the soft magnetic alloy was
produced in the same manner as in Example 8. For the obtained soft
magnetic alloy, in addition to the same evaluation as in Example 8,
the (110) plane spacing was calculated.
[0102] The (110) plane spacing was calculated from 20 of the
strongest peak belonging to the (110) plane among the diffraction
peaks obtained by the XRD measurement and the wavelength of the
measurement X-ray. In addition, for the sample of pure iron, the
(110) plane spacing was calculated under the condition under which
the above XRD measurement was performed using the same device as
that used for the above XRD measurement. By subtracting the
obtained spacing value of the (110) plane of pure iron from the
obtained spacing value of the (110) plane of the soft magnetic
alloy, the expansion values of the (110) plane spacing in the
samples of Example 8 and Examples 35-38 were obtained. The results
are shown in Table 3.
TABLE-US-00003 TABLE 3
Fe.sub.0.820Nb.sub.0.040B.sub.0.100Zn.sub.0.040 .alpha. = .beta. =
0 c = d = e = 0 Fe-based nanocrystal Property Heat treatment
condition Expansion Saturation Second heat Average of 110 Magneto-
magnetic flux Coer- First heat treatment treatment grain plane
striction density civity Compre- Temperature Time Temperature Time
size spacing .lamda. Bs Hc hensive (.degree. C.) (h) (.degree. C.)
(h) (nm) (.ANG.) (.times.10.sup.-6) (T) (A/m) evaluation Example 8
550 1 -- 0 26 0.0029 1.59 1.43 1.3 2 Example 35 550 0.25 450 1 25
0.0026 1.54 1.66 1.7 2 Example 36 550 0.25 450 3 24 0.0020 1.18
1.64 1.8 4 Example 37 550 0.25 450 5 26 0.0016 0.98 1.66 1.7 4
Example 38 550 0.25 450 10 27 0.0005 0.79 1.67 1.8 4
[0103] From Table 3, it was confirmed that the expansion value of
the (110) plane spacing decreases due to the heat treatment at a
lower temperature than that in the first heat treatment and the
magnetostriction also decreases accordingly. Furthermore, it was
confirmed that the expansion value of the (110) plane spacing
decreases when the holding time of the second heat treatment is
prolonged and the magnetostriction also decreases accordingly.
Examples 39-43
[0104] Except that the heat treatment conditions in the sample of
Example 4 were changed to those shown in Table 4, the soft magnetic
alloy was produced in the same manner as in Example 4, and the same
evaluation as in Example 4 was performed. The results are shown in
Table 4.
TABLE-US-00004 TABLE 4 Property
Fe.sub.0.830Nb.sub.0.020B.sub.0.120Zn.sub.0.030 .alpha. = .beta. =
0 c = d = e = 0 Saturation Fe-based Magneto- magnetic flux Coer-
Heat treatment condition nanocrystal striction density civity
Compre- First heat treatment Average grain size .lamda. Bs Hc
hensive Temperature (.degree. C.) Time (h) (nm) (.times.10.sup.-6)
(T) (A/m) evaluation Example 39 400 1 3 2.37 1.41 0.8 2 Example 40
450 1 5 1.49 1.60 1.0 8 Example 41 500 1 21 1.47 1.62 1.1 8 Example
4 550 1 27 1.40 1.65 1.0 8 Example 42 600 1 30 1.42 1.69 1.5 8
Example 43 650 1 32 1.39 1.69 1.9 4
[0105] From Table 4, it was confirmed that good properties are
obtained when the average grain size of the Fe-based nanocrystals
is within the above range.
* * * * *