Note: Descriptions are shown in the official language in which they were submitted.
DEsc~IPrIoN 1317~8~
GLASSY METAL ALLOYS WITH PERMINVAR CHARACT~RISTI~
BACKGROUND OF INVENTION
1. Field of Invention
This invention relates to glassy metal alloys with
Perminvar characteristics that is constant
permeabilities at low magnetic field excitations and
constricted hysteresis loops. More particularly, this
invention provides glassy metal alloys with highly non-
linear magnetic properties at low magnetic excitation
levels.
2. Description of Prior Art
The magnetic response, namely magnetic induction
caused by magnetic excitation, of a typical ferromagnet,
is non-linear characterized by a hysteresis loo~. This
loop usually does not allow a relatively constant
- permeability near the zero-excitation point. To realize
such a feature, so-called Perminvar alloys were
developed [see, for exam~le, R. M. Bozorth,
Ferromagnetism (Van Nostrand, Co., Inc., New York, 1951)
p. 166-180]. These alloys are usually based on
crystalline iron-cobalt-nickel system. Typical
compositions (weight percent) include 20%Fe-60~Co-20%Ni
~20-60 Perminvar) and 30%Fe-25%Co-45%Ni (45-45
Perminvar). Improvements of the crystalline Perminvar
al~oys have been made. Of significance is the addition
of molybdenum, as exemplified by the synthesis of 7.5-
45-25 Mo-Perminvar (7.5%Mo-45%Ni-25%Co-22.5~Fe). This
material, when furnace cooled from 1110C, exhibited a
dc coercivity (Hc) of 40 A/m (=0.5 Oe), initial
permeability ( ~O) of 100 and the remanence (Br) of
0.75 T.
In the advent of modern electronics technology, it
becomes necessary to further improve the Perminvar-like
properties. For example, further reduction Hc and
increase of ~o would be desirable when an efficient
transformer re~uiring low field modulations is needed.
Furthermore, the usual non-linear characteristic of the
, --
-2- 1317484
conventional Perminvar alloys cannot be utilized without
a large level of excitation of well above 80 A/m (=l
Oe). Also desirable in many applications are low ac
magnetic losses. One approach to attain these excellent
5 soft magnetic properties is to reduce the materials'
magnetostriction values as low as possible.
Saturation magnetostriction As is related to the
fractional change in length ~ that occurs in a
magnetic material on going from the demagnetized to the
saturated, ferromagnetic state. The value of
magnetostriction, a dimensionless quantity, is often
given in units of microstrains (i.e., a microstrain is a
fractional change in length of one part per million).
Ferromagnetic alloys of low magnetostriction are
desirable for several interrelated reasons:
1. Soft magnetic properties (low coercivity, high
permeability) are generally obtained when both the
saturation magnetostriction As and the
magnetocrystalline anisotropy K approach zero.
Therefore, given the same anisotropy, alloys of lower
magnetostriction will show lower dc coercivities and
bigher permeabilities. Such alloys are suitable for
various soft magnetic a~plication.
2. Magnetic properties of such zero
magnetostrictive materials are insensitive to mechanical
strains. When this is the case, there is little need
for stress-relief annealing after winding, punching or
other physical handling needed to form a device from
such material. In contrast, magnetic ~ro~erties of
stress-sensitive materials, such as the crystalline
alloys, are seriously degraded by sucb cold workin~ and
such materials must be carefully annealed.
3. The low dc coercivity of zero magnetostrictive
materials carries over to ac operating conditions where
again low coercivity and high permeability are realized
(provided the magnetocrystalline anisotropy is not too
large and the resistivity not too small). AlSo because
energy is not lost to mechanical vibrations when the
_3_ 1 3 1 7'~ 8~
saturation maganetostriction is zero, the core lo~s of
zero magnetostrictive materials can be quite low. Thus,
zero magnetostrictive magnetic alloys (of moderate or
low magnetocrystalline anisotropy) are useful where low
5 loss and high ac permeability are re~uired. SUCh
applications include a variety of tape-wound and
laminated core devices, such as power transformers,
signal transformers, magnetic recording heads and the
like.
4. Finally, electromagnetic devices containing
zero magnetostrictive materials generate no acoustic
noise under AC excitation. While this is the reason for
the lower core loss mentioned above, it is also a
desirable characteristic in itself because it eliminates
the hum inherent in many electromagnetic devices.
There are three well-known crystalline alloys of
zero magnetostriction (in atom percent, unless otherwise
indicated):
(1) Nickel-iron alloys containing approximately
80% nickel (~80 nickel permalloys~);
(2) Cobalt-iron alloys containing ap~roximately
90% cobalt; and
(3) Iron-silicon alloys containing approximately 6
wt. % silicon.
Also included in these categories are zero
magnetostrictive alloys based on the binaries but with
small additions of other elements such as molybdenum,
copper or aluminum to provide specific property
changes. These include, for example, 4% Mo, 79~ Ni, 17
Fe (sold under the designation Moly Permalloy) for
increased resistivity and permeability; permalloy plus
varying amounts of copper (sold under the designation
Mumetal) for magnetic softness and improved ductility;
and 85 wt. % Fe, 9 wt. % Si, 6 wt. % Al (sold under the
designation Sendust) for zero anisotro~y.
The alloys included in category (1) are the most
widely used of the three classes listed above because
they combine zero magnetostriction with low anisotropy
. . .
~4~ 1317~84
and are, therefore, extremely soft magnetically~ that is
they have a low coercivity, a high permeability and a
low core loss. These permalloys are also relatively
soft mechanically and their excellent magnetic
5 pro~erties, achieved by high temperature (above 1000C)
anneal, tend to be degraded by relatively mild
mechanical shock.
Category (2) alloys such as those based on CogOFe10
have a much higher saturation induction (Bs about 1.9
Tesla) than the permalloys. However, they also have a
strong negative magnetocrystalline anisotropy, which
prevents them from being good soft magnetic materials.
For example, the initial permeability of CogOFe10 is
only about 100 to 200.
Category (3) alloys such as Fe-6 wt~ Si and the
related ternary alloy Sendust (mentioned above) also
show higher saturation inductions (BS about 1.8 Tesla
and 1.1 Tesla, respectively) than the permalloys.
However these alloys are extr-emely brittle and have,
therefore, found limited use in powder form only.
Recently both Fe-6.5 wt. % Si lIEEE Trans. MAG-16, 728
(1980)] and Sendust alloys [IEEE Trans. MAG-15, 1149
(1970)] have been made relatively ductile by ra~id
solidification. However, compositional dependence of
the magnetostriction is very strong in these materials,
making difficult precise tayloring of the alloy
composition to achieve near-zero maganetostriction.
It is known that magnetocrystalline anisotropy is
effectively eliminated in the glassy state. It is
therefore, desirable to seek glassy metal alloys of zero
magnetostriction. Such alloys might be found near the
compositions listed above. Because of the presence of
metalloids which tend to reduce the magnetization by
dilution and electronic hybridization, however, glassy
metal alloys based on the 80 nickel permalloys are
either non-magnetic at room temperature or have
unacceptably low saturation inductions. For exam~le,
the glassy alloy Fe40Ni40P14B6 (the subscripts are in
1317~84
--5--
atom percent) has a saturation induction of about 0.8
Tesla, while the glassy alloy Ni49Fe29P14B6Si2 has a
saturation induction of about 0.46 Tesla and the glassy
alloy Ni80P20 is non-magnetic. No glassy metal alloys
5 haviny a saturation magnetostriction approximately e~ual
to zero have yet been found near the iron-rich Sendust
composition. A number of near-zero magnetostrictive
glassy metal alloys based on the Co-Fe crystalline alloy
mentioned above in (2) bave been reported in the
literature. These are, for example, Co72Fe3P16B6A13
(AIP Conference Proceedinys, No. 24, pp. 745-746 (1975))
Co70 5Fe4 5Sil5Blo Vol. 14, Japanese Journal of Applied
Physics, ~p. 1077-1078 (1975)) C31.2Fe7.8Ni39.0~14Si8
lproceedings of 3rd International Conference on ~apidly
Quenched Metals, p. 183, (1979)] and Co74Fe6B20 [IEEE
Trans. MAG-12, 942 (1976)]. However, none of the above-
mentioned near-zero magnetostrictive materials show
Perminvar-like characteristics. By polishing the
surface of a low magnetostrictive glassy ribbon, a
surface uniaxial anisotrpy was introduced along the
polishing direction which resulted in observation of
Perminvar-like Kerr hysteresis loops (Applied Physics
Letters, vol. 36, pp. 339-341 (1980). This is only a
surface effect and is not of a bulk property of the
material, limiting the use of such effect in some
selected devices.
Furthermore, to realize the Perminvar pro~erties,
the crystalline materials mentioned-above have to be
baked for a long time at a given temperature. Typica11y
the heat-treatment is performed at 425C for 24 hours.
Obviously it is desirable to heat-treat the materials at
a temperature as low as possible and for a duration as
short as possiDle.
Clearly desirable are new maynetic materials with
various Perminvar characteristics which are suited for
modern electronics technology.
-6- 13~7~84
SUMMARY OF INVENTION
-
In accordance with the invention, there is ~rovided
a magnetic alloy that is at least 70~ glassy and which
has a low magnetostriction and Perminvar characteristics
5 of relatively constant permeability at low magnetic
field excitations and a constricted hysteresis loop in
addition to excellent soft magnetic properties. The
glassy metal alloy has the composition CoaFebNic~ldBeSif
where M is at least one number selected from the group
10 consisting of Cr, Mo~ Mn and Nb, "a-f" are in atom
percent and the sum of "a-f" equals 100, a ranges from
about 66 to 71, "b" eanges from about 2.5 to 4.5, "c"
ranges from about 0 to 3, "d~ ranges from about 0 to 2
exce~t when M=Mn in which case "d" ranges from about 0
to 4, ~e" ranges from about 6 to 24 and "f" ranges from
about 0 to 19, with the proviso that the sum of ~a~,
"b~, and ~c" ranges from about 72 to 76 and the sum of
"e~ and "f~ ranges from about 25 to 27. The ylassy
alloy has a value of magnetostriction ranging from about
20 ~ lx10 6 to + lx10 6, a saturation induction ranging
from about 0.5 to 1 Tesla, a Curie temperature ranging
from about 200 to 450C and a first crystallization
temperature ranging from about 440 to 570C. The glassy
alloy is heat-treated by heating it to a temperature
25 between about 50 and 110C below its first
crystallization temperature for a time period ranging
from 15 to 180 min., and then cooling the alloy at a
rate slower than about - 60C/min.
DETAILED DESCRIPTION OF THE INVENTION
The glassy alloy is heat-treated at a temperature
Ta for a duration of time ta~ where ~ TC-a = (TCl-Ta) is
between 50 and about 110C; ant ta is between about 15
and 120 minutes, followed by cooling of the material at
a rate slower than about -10C/min. The choice of Ta
and ta should exclude the case that ~ TC_a ~ 50C and ta
~ 15 minutes because such combination sometimes results
in crystallization of the glassy alloy.
1317~8~
--7--
The purity of the above composition is that foun~
in normal commercial practice. However, it would be
appreciated that the metal ~l in the alloys of the
invention may be replaced by at least one other element
5 such as vanadium, tungsten, tantalum, titanium,
zirconium and hafnium, and up to about 4 atom percent of
Si may be replaced by carbon, aluminum or germanium
without significantly degrading the desicable magnetic
properties of these alloys.
Examples of near-zero magnetostrictive glassy metal
alloys of the invention include Co70.5Fe4.5B15Si10,
69.0Fe4.1~il.4M1 5Bl2si
Co65 7Fe4 4Ni2 gMo2Bllsil4~ CO69.2Fe3-8Mo2B8 17
Co67 5Fe4 5Ni3 oB8Sil7~ C70.g8Fe4.1B8S 17'
Co69.9Fe4.lMnl.oB8sil7~ Co6g.oFe4.oMn2B8si
68.0 e4~oMn3B8si17~ Co67 1Fe3 9Mn4B8si17~
68-0 4.0 n2CrlBgSil7~ Co69 OFe4 OCr2B8sil7,
Co69 OFe4 oNb2B8Si17~ C68.2Fe3.8Mnl 12 15
Co67 7Fe3 3Mn2B12Sil5~ C67.8Fe4.2 1 12 15
C67 8Fe4 2CrlB12Sil5~ CO67.0Fe4.0C 2 12 15
Co66 1Fe3 9Cr3B12sils~C68.5Fe2.5Mn4 10 15
CO65.7Fe4.4Ni2.gMO2B23C2 and Co68 6Fe4 4Mo2Ge4B2l.
These alloys possess saturation induction (Bs) between
O.S and 1 Tesla, Curie temperature between 200 and 450C
and excellent ductility. Some magnetic and thermal
properties of these and some of other near-zero
magnetostrictive alloys of the present invention are
listed in Table I.
TABLE I
Saturation induction (Bs), Curie temperature
( ~ f)~ saturation magnetostriction I As) and the first
- crystallization temperature (TCl) of near -zero
magnetostrictive alloys of the present invention.
1317 ~8~
-8-
Compositions
Co Fe Ni ~1 B Si
70.5 4.5 - - 15 10
69.0 4.1 1.4 M~=1.5 12 12
5 65.7 4.4 2.9 M~=2 11 14
68.2 3.8 - Mn=l 12 15
67.7 3.3 - Mn=2 12 15
67.8 4.2 - M~=l 12 15
67.8 4.2 - Cr=l 12 15
10 69.2 3.8 _ M~=2 8 17
67.5 4.5 3.0 - 8 17
70.98 4.1 - - 8 17
69.9 4.1 - Mn=l 8 17
69.0 4.0 - Mn=2 8 17
15 68.0 4.0 - Mn=3 8 17
67.1 3.9 - Mn=4 8 17
69.0 4.0 - Cr=2 8 17
68.0 4.0 - Mn=2,Cr=1 8 17
69.0 4.0 - ~b=2 8 17
20 65.7 4.4 2.9 Mo=2 23 C=3*
65.7 4.4 2.9 Moc2 23 2
69.5 4.1 1.4 - 6 19
58.6 4.4 - Mb--2 21 Ge=4*
70.5 4.5 - - 24 Ge=l*
25 67.0 4.0 - Cr=2 12 15
69.2 3.8 - Mb=2 10 15
68.1 4.0 1.4 Mo=1.5 8 17
69.0 3.0 - Mn=3 10 15
68.5 2.5 - Mn=4 10 15
30 68.8 4.2 - Cr=2 10 15
* All Si content is replaced by the indicated element and amount.
- -` 1317~84
g
B~(Tesla) ~ f(C) A s(10 6) T~1(C)
0.82 422 -0.3 517
0.73 324 0 520
0.77 246 0 530
5 0.70 266 +0.4 558
0.71 246 +0.4 560
0.62 227 +0.4 556
0.64 234 +0.6 561
0.67 295 +0.5 515
10 0 73 32g +0.5 491
0.77 343 -0.4 490
0.77 331 -0.5 493
0.75 312 +0.8 502
0.74 271 +0.9 507
15 0 74 269 -0.8 512
0.63 261 +0.2 503
0.69 231 +0.7 511
0.62 256 +0.4 541
0.76 393 o 500
0.79 402 0 512
0.73 316 -0.1 443
0.77 365 0 570
0.99 451 -0.4 494
0.57 197 +0.4 480
25 0.72 245 +0.4 541
0.67 276 +0.4 512
0.79 305 +1.1 544
0.78 273 +0.4 548
0.69 261 +0.4 540
Figure 1 illustrates the B(induction)-H(applied
field) hysteresis loops for a near-zero magnetostrictive
C67 8Fe4 2crlB12sil5 glassy alloy heat-treated at Ta =
460C (A), Ta = 480C (B) and Ta = 500C (C) for 15
minutes, followed by cooling at a rate of about
-5C/min. The constricted B-H loops of Figs lB and lC
are characteristic of the materials with Perminvar-like
properties, whereas the B-H loop of Fig. lA corresponds
~:
... . .
-
-lo- 1 31 7~8~
to that of a typical soft ferromagnet. As evidenced in
Figure 1, the choice of the heat-treatment temperature
Ta is very important in obtaining the Perminvar
characteristics in the glassy alloys of the peresent
invention. Table II summarizes the heat-treatment
conditions for some of these alloys and some of the
resultant magnetic properties.
Table II
Heat-treatment temperature (Ta) and duration ~ta)
to obtain Perminvar characteristics in the glassy
alloys of the present invention. ~ TC-a is equal to
(TCl ~Ta)~ Cooling rate is about -5C/min. unless
stated otherwise. The quantity ~O is the initial dc
permeability and Hc is the coercivity obtained after the
heat-treatment.
Com~ositions
Co Fe Ni M - B Si
70.5 4.5 - - 15 10
70.5 4.5 - - 15 10
70.5 4.5 - - 15 10
69.0 4.1 1.4Mo=1.5 12 12
69.0 4.1 1.4Mo=1.5 12 12
65.7 4.4 2.9Mo=2 11 14
68.2 3.8 - Mn=l 12 15
68.2 3.8 - Mn=l 12 15
67.7 3.3 - Mn=2 12 15
67.7 3.3 - Mn=2 12 15
67.8 4.2 - Mo=l 12 15
67.8 4.2 - Cr=l 12 15
67.8 4.2 - Cr=l 12 15
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mos2 8 17
69.2 3.8 - Mn=2 8 17
67.5 4.5 3.0 - 8 17
67.5 4.5 3.0 - 8 17
131~
--11--
Compositions
Co Fe Ni M ~ ~i
67.5 4.5 3.0 - 8 17
67.5 4.5 3.0 - 8 17
70.98 4.1 - - 8 17
70.98 4.1 - - 8 17
69.9 4.1 - Mn=l 8 17
69.9 4.1 - Mn=l 8 11
69.0 4.0 - Mn=2 8 17
69.0 4.0 - Mn=2 8 17
68.0 4.0 - Mn=3 8 17
68.0 4.0 - Mn=3 8 17
67.1 3,9 - Mn-4 8 17
69.0 4.0 - Cr=2 8 17
69.0 4.0 - Cr=2 8 17
68.0 4.0 -Mn=2,Cr=1 8 17
68.0 4.0 -Mn=2,Cr=1 8 17
69.0 4.0 - Nb=2 8 17
68.1 4.0 1.4Mo=1.5 8 17
68.1 4.0 1.4Mo=1.5 8 17
65.7 4.4 2.9Mo=2 23 C=3*
65.7 4.4 2.9Mo=2 23 2
69.5 4.1 1.4 - 6 19
68.5 4.4 - Mo=2 21 Ge=4*
70.5 4.5 - - 24 Ge=l*
69.2 3.8 - Mo=2 10 15
69.2 3.8 - Mo=2 10 15
69.0 3.0 - Mo=3 10 15
68.5 2.5 - Mn=4 10 lS
68.8 4.2 - Cr=2 10 15
* All of Si content is replaced by the indicated
element.
-12-1317~8~
T~ (C) t~(min .) ~ Tr_~ (C) Hr (A/m) ~ ~
460 lS 57 3.47,900
460 lS** 57 3.1S,700
460 lS*** 57 1.47,600
430 120 90 1.24,000
430 150 90 3.64,000
420 180 100 6.412,250
420 lS 110 4.033,000
480 15 78 0.2019,000
500 15 58 7.613,000
480 15 80 0.2022,000
500 15 60 0.2022,000
500 15 56 0.4490,000
480 15 81 0.2050,000
500 15 61 0.4430,000
460 15 55 4.29,700
460 30 55 4.910,000
460 45 55 4.58,000
460 90 55 5.07,500
460 105 55 3.97,900
380 45 111 4.712,700
380 60 111 4.59,600
380 90 111 3.611,500
380 105 111 5.015,800
420 15 71 3.67,200
400 15 90 7.05,000
420 lS 70 2.02,400
400 15 93 1.72,500
420 15 73 0.843,600
400 15 102 3.213,000
420 15 82 0.985,00~
400 15 107 2.029,000
420 15 87 3.321,500
420 15 92 0.7015,800
420 15 83 0.8024,000
440 lS 63 0.8421,500
420 15 91 1.431,500
440 lS 71 1.124,000
-13- 1317~8~
T~(C) t?(min.) ~ T~_a(C) Hr(A/m)~o
440 15 101 3.428,700
440 15 72 2.935,800
46Q 15 52 3.619,300
440 15 60 5.6 2,300
450 15 62 10.4 8,000
380 15 63 12 3,300
480 15 90 5.217,000
420 15 74 6 600
450 60 91 1.521,000
460 60 81 1.619,300
440 15 104 1.217,500
440 15 108 1.223,000
460 15 80 0.820, oao
This table teaches the importance of the quantity
~ Tc a being between about 50 and 110C and relatively
slow cooling rates after the heat-treatments at
temperature Ta and for the duration ta. It is also
noted that ~O values are higher and the Hc values are
lower than those of prior art materials. For example, a
properly heat-treated (Ta = 460C; ta = 15 min.)
67.8 e4.2crlB12sils glassy alloy exhibits ~ = 50 ooo
and Hc = 0.2 A/m whereas one of the improved prior art
,alloy, namely 7.5-45-25 Mo-Perminvar, gives ~O = 100
and Hc = 40 A/m when furnace cooled from 1100C and
gives ~O = 3,500 when quenched from 600C.
In many magnetic applications, lower
magnetostriction is desirable. For some applications,
however, it may be desirable or acceptable to use
materials with a small positive or negative
magnetostriction. Such near-zero magnetostrictive
glassy metal alloys are obtained for a, b, c in the
ranges of about 66 to 71, 2.5 to 4.5 and 0 to 3 atom
percent respectively, with the proviso that the sum of
a, b, and c ranges between 72 and 76 atom percent. The
absolute value of saturation magnetostriction ¦ ~sl f
these glassy alloys is less than about lxlO 6 (i.e. the
', ,A~
131 7 18~
-14-
saturation magnetostriction ranges from about -lx10-6 to
+lx10-6 or from -1 to +1 microstrains~.
The glassy alloys of the invention are conveniently
prepared by techniques readily available elsewhere; see
e.g. US Patent No. 3,845,805 issued November 5, 1974 and
No. 3,856,513 issued December 24, 1974. In general, the
glassy alloys, in the form of continuous ribbon, wire,
etc., are rapidly quenched from a melt of the desired
composition at a rate of at least about 105 K/sec.
A metalloid content of boron and silicon in the
range of about 25 to 27 atom percent of the total alloy
composition is sufficient for glass formation with boron
ranging from about 6 to 24 atom percent. It is
prefered, however, that the content of metal M, i.e. the
quantity d does not exceed very much from about 2 atom
percent except when M=Mn to maintain a reasonably high
Curie temperature t> 200C).
In addition to the highly non-linear nature of the
glassy Perminvar alloys of the present invention, these
alloys exhibit high permeabilities and low core loss at
high frequencies. Some examples of these features are
given in Table III.
Table III
Core loss (L) and impedance permeability ( ~) at
f=50 kHz and induction level of 0.1 Tesla for some of
the glassy Perminvar-like alloys of the present
invention. Ta and ta are heat-treatment temperature and
time. Cooling after the heat-treatment is about
-5C/min., unless otherwise stated.
-15- 1317~
Compositions
Co Fe Ni M B ~i
70.5 4.5 - - 15 10
70.5 4.5 - - 15 10
70.5 4.5 - - 15 10
69.0 4.1 1.4Mo=l.S 12 12
65.7 4.4 2.9Mo=2 11 14
68.2 3.8 - Mn=l 12 15
68.2 3.8 - Mn=l 12 15
67.7 3.3 - Mn~2 12 15
67.7 3.3 - Mn=2 12 15
67.8 4.2 - Mo=l 12 15
67.8 4.2 - Cr=l 12 lS
67.8 4.2 - Cr=l 12 15
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
69.2 3.8 - Mo=2 8 17
67.5 4.5 3.0 - 8 17
67.5 4.5 3.0 - 8 L7
67.5 4.5 3.0 - 8 17
67.5 4.5 3.0 - 8 17
67.5 4.5 3.0 - 8 17
70.9 4.1 - - 8 17
70.98 4.1 - - 8 17
69.9 4.1 - Mn=l 8 17
69.9 4.1 - Mn=l 8 17
69.0 4.0 - Mn=2 8 17
69.0 4.0 - Mn=2 8 17
68.0 4.0 - Mn=3 8 17
68.0 4.0 - Mn=3 8 17
67.1 3.9 - Mn=4 8 17
69.0 4.0 - Cr-2 8 17
69.0 4.0 - Cr=2 8 17
68.0 4.0 -Mn=2, Cr=l 8 17
~68.0 4.0 -Mn=2, Cr=l 8 17
69.1 4.0 - Nb=2 8 17
68.1 4.0 1.4Mo=1.5 8 17
,~
-~ -16- 1317~8~
Co Fe Ni M B Si
68.1 4.0 1.4Mo=1.5 8 17
65.7 4.4 2.7Mo~2 23 C=3*
65.7 4.4 2.9Mo~2 23 2
68.6 4.4 - Mo-2 21 Ge=4*
69.2 3.8 - Mo=2 10 15
69.0 3.0 - Mn=3 10 15
68.5 2.5 - Mn=4 10 15
68.8 4.2 - Cr=2 10 15
* All of Si content is replaced by the indicated
element.
.
-- 1317~
- 17 -
T~(C) t~(min.) L(W/kg)
460 15 352,300
460 15** 392,000
460 15*** 143,400
430 120 142,800
420 15 6.76,000
480 15 4.614,000
500 15 4.4~,300
480 15 4.017,600
500 15 4.517,000
500 15 4.027,600
480 15 4.024,700
500 15 3.722,500
460 15 9.05,400
460 30 6.314,900
460 45 6.613,800
460 90 6.714,400
460 105 6.914,800
380 45 193,000
380 60 202,800
380 90 212,900
~ 380 105 182,900
420 15 223,000
400 15 312,400
420 15 152,000
400 15 232,800
420 15 162,700
400 15 113,800
420 15 113,800
400 15 8.05,500
420 15 105,200
420 15 5.79,250
420 15 5.512,500
440 15 4.713,200
420 15 4.810,000
440 15 4.710,500
440 15 4.211,200
440 15 6.68,200
-18- 1 3 1 7 ~ ~ 'L~
Ta(C) t~(min.) L(W/kg)~ _
460 15 7.27,100
440 15 20 2,000
450 15 27 2,800
480 15 9.75,200
450 60 9.19,600
460 60 10 7,700
440 15 8.3~,500
440 15 8.38,200
460 15 5.710,300
** Cooling rate Y -3C/min.
*** Cooling rate ~ -60C/min.
EXAMPLES
1. Sample Preparation
The glassy alloys listed in Tables I-III were
rapidly quenched (about 106 K/sec) from the melt
following the techniques taught by Chen and Polk in U.S
Patent 3,856,513. The resu]ting ribbons, typically 25
to 30 ~m thick and 0.5 to 2.5 cm wide, were determined
to be free of significant crystallinity by X-ray
diffractometry (using CuK radiation) and scanning
calorimetry. Ribbons of the glassy metal alloys were
strong, shiny, hard and ductile.
2 Magnetic Measurements
.
Continuous ribbons of the glassy metal alloys
prepared in accordance with the procedure described in
Example I were wound onto bobbins (3.8 cm O.D.) to form
closed-magnetic-path toroidal samples. Each sample
contained from 1 to 3 9 of ribbon. Insulated primary
and secondary windings (numbering at least 10 each) were
applied to the toroids. These samples were used to
obtain hysteresis loops (coercivity and remanence) and
initial permeability with a commercial curve tracer and
core loss (IEEE Standard 106-1972).
The saturation magnetization, Ms~ of each sample,
was measured with a commercial vibrating sample
. ,
-lg- 1~17~
magnetometer (Princeton Applied Research). In this
case, the ribbon was cut into sevecal small squares
(approximately 2 mm x 2 mm). These wer~ randomly
oriented about their normal direction, their plane being
parallel to the applied field (0 to 720 kA/m. The
saturation induction Bs (=4 ~MSD) was then calculated by
using the measured mass density D.
The ferromagnetic Curie temperature ( ~f) was
measured by inductance method and also monitored by
differential scanning calorimetry, which was used
primarily to determine the crystallization temperatures.
Magnetostriction measurements employed metallic
strain gauges (BLH Electronics), which were bonded
(Eastman - 910 Cement) between two short lengths of
ribbon. The ribbon axis and gauge axis were parallel.
The magnetostriction was determined as a function of
applied field from the longitudinal s~rain in the
parallel ( ~Q/ Q) ~ and perpendicular ( ~ Q/Q) 1 in-
plain fields, according to the formula ~ = 2/3 ~(QQ/Q)~
- ( ~Q/Q) 1 ]
Having thus described the invention in rather full
detail, it will be understood that this detail need not
be strictly adhered to but that further changes and
modifications may suggest themselves to one skilled in
the art, all falling within the scope of the invention
as defined by the subjoined claims.
