CA1222647A - Near-zero magnetostrictive glassy metal alloys with high magnetic and thermal stability - Google Patents
Near-zero magnetostrictive glassy metal alloys with high magnetic and thermal stabilityInfo
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- CA1222647A CA1222647A CA000418542A CA418542A CA1222647A CA 1222647 A CA1222647 A CA 1222647A CA 000418542 A CA000418542 A CA 000418542A CA 418542 A CA418542 A CA 418542A CA 1222647 A CA1222647 A CA 1222647A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C45/00—Amorphous alloys
- C22C45/04—Amorphous alloys with nickel or cobalt as the major constituent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/147—Alloys characterised by their composition
- H01F1/153—Amorphous metallic alloys, e.g. glassy metals
- H01F1/15316—Amorphous metallic alloys, e.g. glassy metals based on Co
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Abstract
ABSTRACT
NEAR-ZERO MAGNETOSTRICTIVE GLASSY METAL
ALLOYS WITH HIGH MAGNETIC AND THERMAL STABILITY
.
A new series of glassy metal alloys with near-zero magnetostriction is disclosed. The glassy alloys have the composition CoaFebNicModBesif, where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom percent, c ranges from about O to 8 atom percent, d ranges from about 1 to 2 atom percent, e ranges from about 11 to 15 atom percent and f ranges from about 9 to 14 atom percent with the proviso that the sum of a, b, c ranges from about 72 to 76 atom per-cent and the sum of e and f ranges from about 23 to 26 atom percent. The magnetostriction of these alloys ranges from about -1 x 10-6 to +1 x 10-6 and the saturation induction is between about 0.6 and 0.8 Tesla. The transition metal content is responsible for the low magnetostriction in these alloys. The metalloid content strongly affects the saturation induction, Curie temperature, and magnetic stability.
Magnetostriction is mildly affected by the metalloid composition and a particular range of Si/B ratio for cértain iron, cobalt containing alloys wherein the magnetostriction is near-zero and relatively insen-sitive to the Si/B ratio. The same Si/B ratios also provide high magnetic stability.
NEAR-ZERO MAGNETOSTRICTIVE GLASSY METAL
ALLOYS WITH HIGH MAGNETIC AND THERMAL STABILITY
.
A new series of glassy metal alloys with near-zero magnetostriction is disclosed. The glassy alloys have the composition CoaFebNicModBesif, where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom percent, c ranges from about O to 8 atom percent, d ranges from about 1 to 2 atom percent, e ranges from about 11 to 15 atom percent and f ranges from about 9 to 14 atom percent with the proviso that the sum of a, b, c ranges from about 72 to 76 atom per-cent and the sum of e and f ranges from about 23 to 26 atom percent. The magnetostriction of these alloys ranges from about -1 x 10-6 to +1 x 10-6 and the saturation induction is between about 0.6 and 0.8 Tesla. The transition metal content is responsible for the low magnetostriction in these alloys. The metalloid content strongly affects the saturation induction, Curie temperature, and magnetic stability.
Magnetostriction is mildly affected by the metalloid composition and a particular range of Si/B ratio for cértain iron, cobalt containing alloys wherein the magnetostriction is near-zero and relatively insen-sitive to the Si/B ratio. The same Si/B ratios also provide high magnetic stability.
Description
~22647 DESCRIPTION
NEAR~ZERO MAGNETOSTRICTIVE GLASSY METAL
ALLOYS WITH HIGH MAGNETIC AND THERMAL STABILITY
BACKGROUND OF THE INVEN~ION
1. Field of the Invention _ This invention relates to glassy metal alloys with near-zero magnetostriction, high magnetic and thermal stability and excellent soft magnetic proper-ties.
NEAR~ZERO MAGNETOSTRICTIVE GLASSY METAL
ALLOYS WITH HIGH MAGNETIC AND THERMAL STABILITY
BACKGROUND OF THE INVEN~ION
1. Field of the Invention _ This invention relates to glassy metal alloys with near-zero magnetostriction, high magnetic and thermal stability and excellent soft magnetic proper-ties.
2. Description of the Prior Art __ _ Saturation magnetostriction ~s is related to the frac~ional change in length ~Q/Q that occurs in a magnetic material on going from the demagnetized to the saturated, ferromagnetic state. The value of magne-tostriction, a dimensionless quantity, is often given in units of microstrains ti.e-, a microstrain is a fractional change in length of one part per million).
Ferromagnetic alloys of low magnetostriction are desirable for several interre:Lated reasons:
1. Soft magnetic properties (low coercivity, high permeability) are generally obtained when both the saturation magnetostriction~sand the magnetocrystalline anisotropy K approach zero. Therefore, given the same anisotropy, alloys of lower magnetostriction will show lower dc coercivities and higher permeabilities. Such alloys are suitable for various soft magnetic applica-tions.
2~ Magnetic properties of such zero magne-toskrictive materials are insensitive to mechanical strains. When this is the case, there is little need ~.
. ., 122;~64~
for stress-relief annealing after winding, punching or other physical handling needed to form a device from such material. In contrast, magnetic properties of stress-sensitive materials, such as the crystalline alloys, are seriously degraded by such cold working and such materials must be carefully annealed.
Ferromagnetic alloys of low magnetostriction are desirable for several interre:Lated reasons:
1. Soft magnetic properties (low coercivity, high permeability) are generally obtained when both the saturation magnetostriction~sand the magnetocrystalline anisotropy K approach zero. Therefore, given the same anisotropy, alloys of lower magnetostriction will show lower dc coercivities and higher permeabilities. Such alloys are suitable for various soft magnetic applica-tions.
2~ Magnetic properties of such zero magne-toskrictive materials are insensitive to mechanical strains. When this is the case, there is little need ~.
. ., 122;~64~
for stress-relief annealing after winding, punching or other physical handling needed to form a device from such material. In contrast, magnetic properties of stress-sensitive materials, such as the crystalline alloys, are seriously degraded by such cold working and such materials must be carefully annealed.
3. The low dc coercivity of zero magneto-strictive materials carries over to ac operating con-ditions where again low coercivity and high permeability are realized (provided the magneto-crystalline anisotropy is not too lar~e and the resistivity not too small). Also hecause energy is not lost to mechanical vibrations when the saturation maga-netostriction is zero, the core loss of zero magne-tostrictive materials can be quite low~ Thus, zeromagnetostrictive magnetic alloys (of moderate or low magnetocrystalline anisotropy) are useful where low loss and high ac permeability are required. Such applications include a variety of tape-wound and lami-nated core devices, such as power transformers, signaltransformers, magnetic recording heads and the like.
4. Finally, electromagnetic devices con-taining zero magnetostrictive materials generate no acoustic noise under AC excitation. While thi~ is the reason for the lower core loss mentioned above, it is also a desirable characteristic in itsel~ 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 approxima-tely 80% nickel ("80 nickel permalloys");
(2) Cobalt-iron alloys containing approxima-tely 90% cobalt; and (3) Iron-silicon alloys containing approxima-tcly 6 wt. ~ silicon.
Also included in these categories are zero ` _3~ 6~7 magnetostrictive alloys based on the binaries but with small additions of other elements such as molybdenum, copper or aluminum to provide specific property chanyes.
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, a registered trademark of Spang Industries, Inc.) for magnetic softness and improved ductility; and 85 wt. ~
Fe, 9 wt. % Si, 6 wt. % Al (sold under the designation Sendust) for zero anisotropy.
The alloys included in category (1) are the most widely used of the three classes listed above be-cause they combine zero magnetostriction with low anisotropy and are, therefore, extremely soft magneti-cally; that is they have a low coercivity, a high permeability and a low core loss. These permallays are also relatively soft mechanically and their excellent magnetic properties, achieved by high temperature (about lOO~C) 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 Co90Fe10 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 extremely brittle and have, therefore, found limited use in powder form only. Recently both Fe/6.5 wt% Si [IEEE Trans. M G-16, 728 (1980)] and Sendust alloys [IEEE Trans. MAG-15, 1149 (1970)] have been made relatively ductile by rapid solidification. However, compositional dependence o~ the magnetostriction is very strong in these materials, ~' ~ 4 -~ ~Z~Z~47 difficult precise tayloring of the alloy composition to achieve near-zero maganetostriction.
It is known that magnetocrystalline anisotropy i5 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 quench the magnetization by the transfer of charge to the transition-metal d-electron states, however, glassy metal alloys based onthe 80 nickel permalloys are either non-magnetic at room temperature or have unacceptably lo~ saturation induction~. For example, the glassy alloy Fe40Ni40P14B6 (the subscripts are in 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 Ni80P~o is non-magnetic. No glassy metal alloys having a saturation magnetostriction approximately equal 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) have been reported in the literature.
These are, for example, Co72Fe3P16s6A13 (AIP ConferenCe Proceedings, ~o. 24, pp. 745-746 (1975)) 70.5Fe4.ssilsBlo (Vol- 14, Japanese ~ournal of Appll Physics, pp. 1077-1078 (1975)) C31.2Fe7.8Ni39.0B14Sig [proceedings of 3rd International Conference on Rapidly Quenched Metals, p.
183, (1979)] and CO74Fe6B20 [IEEE Trans. AG-12, 942 (1976)]. rrable I lists some of the magnetic properties of these materials.
T le Saturation induction (Bs), Curie temperature (~
the first crystallization temperature (TC1) r as-cast dc coe~civity (HC), and dc coercivity and permeability ( ~ ) in the annealed states of some oE the prior art zero magnetostrictive glassy alloys.
`-` 122;269~7 nnealed V lues Alloy Bs ef TC H~ H~ ~
(Tesla) (K) (K~ ~A/m) (A~m) (at 1 ~z) C72Fe3P16B6A13 0.63 600 - 1.8 1.0*
There are three well-known crystalline alloys of zero magnetostriction (in atom percent, unless otherwise indicated) (1) Nickel-iron alloys containing approxima-tely 80% nickel ("80 nickel permalloys");
(2) Cobalt-iron alloys containing approxima-tely 90% cobalt; and (3) Iron-silicon alloys containing approxima-tcly 6 wt. ~ silicon.
Also included in these categories are zero ` _3~ 6~7 magnetostrictive alloys based on the binaries but with small additions of other elements such as molybdenum, copper or aluminum to provide specific property chanyes.
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, a registered trademark of Spang Industries, Inc.) for magnetic softness and improved ductility; and 85 wt. ~
Fe, 9 wt. % Si, 6 wt. % Al (sold under the designation Sendust) for zero anisotropy.
The alloys included in category (1) are the most widely used of the three classes listed above be-cause they combine zero magnetostriction with low anisotropy and are, therefore, extremely soft magneti-cally; that is they have a low coercivity, a high permeability and a low core loss. These permallays are also relatively soft mechanically and their excellent magnetic properties, achieved by high temperature (about lOO~C) 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 Co90Fe10 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 extremely brittle and have, therefore, found limited use in powder form only. Recently both Fe/6.5 wt% Si [IEEE Trans. M G-16, 728 (1980)] and Sendust alloys [IEEE Trans. MAG-15, 1149 (1970)] have been made relatively ductile by rapid solidification. However, compositional dependence o~ the magnetostriction is very strong in these materials, ~' ~ 4 -~ ~Z~Z~47 difficult precise tayloring of the alloy composition to achieve near-zero maganetostriction.
It is known that magnetocrystalline anisotropy i5 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 quench the magnetization by the transfer of charge to the transition-metal d-electron states, however, glassy metal alloys based onthe 80 nickel permalloys are either non-magnetic at room temperature or have unacceptably lo~ saturation induction~. For example, the glassy alloy Fe40Ni40P14B6 (the subscripts are in 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 Ni80P~o is non-magnetic. No glassy metal alloys having a saturation magnetostriction approximately equal 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) have been reported in the literature.
These are, for example, Co72Fe3P16s6A13 (AIP ConferenCe Proceedings, ~o. 24, pp. 745-746 (1975)) 70.5Fe4.ssilsBlo (Vol- 14, Japanese ~ournal of Appll Physics, pp. 1077-1078 (1975)) C31.2Fe7.8Ni39.0B14Sig [proceedings of 3rd International Conference on Rapidly Quenched Metals, p.
183, (1979)] and CO74Fe6B20 [IEEE Trans. AG-12, 942 (1976)]. rrable I lists some of the magnetic properties of these materials.
T le Saturation induction (Bs), Curie temperature (~
the first crystallization temperature (TC1) r as-cast dc coe~civity (HC), and dc coercivity and permeability ( ~ ) in the annealed states of some oE the prior art zero magnetostrictive glassy alloys.
`-` 122;269~7 nnealed V lues Alloy Bs ef TC H~ H~ ~
(Tesla) (K) (K~ ~A/m) (A~m) (at 1 ~z) C72Fe3P16B6A13 0.63 600 - 1.8 1.0*
5 Co70~5Fe4~sBloSil5 0.65 688 - 8.0 1.2** 50 000 Co31.2Fe7.8N139 0.61 503690 - 0~16*** 50 000 B14Si8 CO74Fe6B20 1.18 7006~0 2.8 * annealed at 270~C for 45 min., in 2400 A/m field 10 (Hll) applied along the circumferential direction of the toroidal sample.
** annealed at 350C and cooled at 175C/hour in Hll =
32 kA/m.
***annealed at about 330C.
The saturation induction (Bs) of these alloys ranges between 0.6 and 1.2 Tesla. The glassy alloys with Bs close to 0.6 T show low coercivities and high per-meabilities comparable to crystalline supermalloys.
However, these alloys tend to be magnetically unstable at relatively low ( 150C) temperatures. On the other hand, the glassy alloys with Bs ~ 1.2 Tesla tend to have their ferromagnetic Curie temperatures (ef) near or above their first crystallization temperatures (TCl).
This makes heat-treatment of these materials very dif-ficult to achieve desired soft magnetic propertiesbecause such annealing is most effective when carried out at temperatures near ef.
Clearly desirable are zero magnetostrictive glassy alloys with higher magnetic and thermal stability and a saturation induction as high as possible.
SUMMARY OF THE INVENTION
In accordance with the invention, there is provided a magnetic alloy that is at least 70% glassy~ and which has a near-zero magnetostriction, high magnetic and thermal stability and excellent soft magnetic proper-ties. The glassy metal alloy has the composition coaFebNicMo~Besi~ where A ranges ~rom about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom
** annealed at 350C and cooled at 175C/hour in Hll =
32 kA/m.
***annealed at about 330C.
The saturation induction (Bs) of these alloys ranges between 0.6 and 1.2 Tesla. The glassy alloys with Bs close to 0.6 T show low coercivities and high per-meabilities comparable to crystalline supermalloys.
However, these alloys tend to be magnetically unstable at relatively low ( 150C) temperatures. On the other hand, the glassy alloys with Bs ~ 1.2 Tesla tend to have their ferromagnetic Curie temperatures (ef) near or above their first crystallization temperatures (TCl).
This makes heat-treatment of these materials very dif-ficult to achieve desired soft magnetic propertiesbecause such annealing is most effective when carried out at temperatures near ef.
Clearly desirable are zero magnetostrictive glassy alloys with higher magnetic and thermal stability and a saturation induction as high as possible.
SUMMARY OF THE INVENTION
In accordance with the invention, there is provided a magnetic alloy that is at least 70% glassy~ and which has a near-zero magnetostriction, high magnetic and thermal stability and excellent soft magnetic proper-ties. The glassy metal alloy has the composition coaFebNicMo~Besi~ where A ranges ~rom about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom
6~
percent, c ranges from about 0 to 8 atom percent, d ranges from about 1 to about 2 atom percent, e ranges from about 11 to lS atom percent and f ranges from about 9 to 1~ atom percent, with the proviso that the sum of a, b and c ranges from about 72 to 76 atom percent and the sum of e and f ranges from about 23 to 26 atom percent. The glassy alloy has a value of magnetostric-tion ranging from about -1 x 10-6 to +1 x 10-6 a saturation induction ranging from about 0.6 to 0.8 Tesla, a Curie temperature ranging from about 550 to 670K
and a first crystallization temperature ranging from about 790 to 870 X.
DETAILED DESCRIPTION OF THE INVENTION
~ ___ _ In accordance with the invention, there is provided a magnetic alloy that is at least 70% glassy and which has an outstanding combination of properties, including a near-zero magnetostriction, high magnetic and thermal stability and such soft magnetic properties as high permeability, low core loss and low coercivity.
The glassy metal alloy has the composition COaFebNicModBeSif, where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom per-cent, c ranges from about 0 to 8 ato~ percent and d ranges from about 1 to about 2 atom percent, e ranges from about 11 to 15 atom percent and ~ ranges from about 9 to 14 atom percent, with ~he proviso that the sum of a, b and c ranges from about 72 to 76 atom per-cent and the sum of e and f ranges from about 23 to 26 atom percent. The glassy alloy has a value of magneto-striction ranging from about -1 x 10-6 to +1 x 10-6 and a saturation induction ranging from about 0.6 to 0.8 Tesla, Curie Temperature, ranging from 550 to 670K and the first crystallization temperature ranging from about 790 to 870 K.
The purity of the above composition is that found in normal commercial practice. However, it will be appreciated that molybdenum in the alloys of the invention may be re~laced by at least one other tran-l~ZZ64~7 sition metal element, such as tungsten, niobium, tan-talum, titanium, zirconium and hafnium, and up to about 2 atom percent of Si may be replaced by carbon, alu-minum or germanium without significantly degrading the desirable magnetic properties of these glassy alloys.
Examples of essentially zero magnetostrictive glassy metal alloys of the invention include C67.4Fe4.1Ni3.0Ml.5B12.5Sill.5, Co67.lFe4.4Ni3.0Mol.s B12.5Sill.5r C64.0Fe4.5Ni6.0M1O5B12.5Sill.5~ C67.0 Fe4.5Ni3.0M1.5B12Sil2r Co~7.oFe4.sNi3.oMol.sBl3sill and Co67.5Fe4.5Ni3.0Mol.oBl2sil2. These glassy alloys possess saturation induction between about 0.7 and 0.8 Tesla, Curie temperature between 600 and 670K, the first crystallization temperature of about 800K and excellent ductility. Some magnetic and thermal proper-ties of these and some of other near-~ero magnetostric-tive glassy alloys of the present invention are listed in Table II. These may be compared with properties listed in Table I for previously-reported glassy metal alloys of zero magnetostriction.
The activation energy (Ea) for the reorien-tation of the magnetization is listed in Table III
for some representative near-zero magnetostrictive glassy alloys. This table indicates that Si tends to increase Ea and also that Ea tends to be higher when Si/B ratio is close to 1. The higher values of Ear indicating higher magnetic stability of the system, is desired. Combining these information based Table II
and III, preferred Si content is between 9 and 14 atom percent when (Si ~ ~) is between 23 and 26 atom percent.
The presence of Mo is to increase TC1 and hence the thermal stability of the alloy system. The content of Mo beyond 2 atom percent, however, reduces the Curie temperature to a level lower than 550 K, which is undesirab]e in convention magnetic devices.
~-`` lZ~26~7 Table II
Saturation induction ~Bs), Curie temperature (a~), saturation magnetostriction ( ~s) and the first ~rystallization tempera~ure (TCl) of near-zero magnetostrictive glassy alloys.
Ccmposl ons Co Fe Ni Mo B Si B~(Tesla) ~(K) S(10-6) T ~K) ._ c 67.4 4.1 3.0 1,5 12.5 11.5 0.72 603 -0.0 798 67.1 4~4 3.0 1.5 12.5 11.5 0.75 626 +0.0 798 64.0 4.5 6.0 1.5 1205 11.5 0.70 620 -0.0 796 10 65.5 4.5 4.5 1.5 12.5 11.5 0.74 620 +0.8 799 70.0 4.5 0 1.5 12.5 11.5 0.77 649 +0.8 800 68.5 4.5 1.5 1.5 12.5 11.5 0.78 639 -0.9 801 63.3 3.7 7.5 1.5 12.5 11.5 ~.66 575 -0.7 798 67.0 4.5 3.0 1.511 13 0.72 582 +0.4 801 15 67.0 4.5 3O0 1~512 12 0.70 598 +0.0 803 67.0 4.5 3.0 1.513 11 0.74 654 +0.0 797 67.0 4.5 3.0 1.514 10 0.74 637 +0.4 800 67.8 3.7 3.0 1.511 13 0.70 558 -0.4 7g9 67.8 3.7 3.0 1.512 12 0.70 585 -0.2 804 20 67.8 3.7 3.0 1.513 11 0.70 600 -0.4 797 67.8 3.7 3.0 1.514 10 0.72 Ç23 -0.6 798 67.8 3.7 3.0 1.515 9 0.72 640 -0.6 794 66.3 5.2 3.0 1.512 12 0.72 586 +0.6 800 68.5 3.0 3.0 1.512 12 0.70 609 -0.3 796 25 69.3 2.2 3.0 1.512 12 0.70 580 -1.1 794 ~7.5 4.5 3.0 1.012 1~ 0.75 672 +0.0 810 66.6 4.4 3.0 2.012 12 0.69 610 +0.6 802 68.0 3.0 3.0 2.012 12 0.68 567 +0.8 867 62.2 5.9 5.9 2.012 12 0.69 578 +1.1 806 30 63.6 5.9 4.4 2.012 12 0.65 563 +0~8 808 65.1 5.9 3.0 2.012 12 0.68 549 +0.8 810 66.6 5.9 1.5 2.012 12 0.71 581 +1.1 808 63.0 6.0 6.0 2.012 11 0.71 673 +0.? 795 67.1 5.4 0 2.0 12.5 13 0.72 643 +0.5 820 35 58.4 7.3 7~3 2.013 12 0.62 570 +0.7 824 '7 TABLE III
Activation energy (Ea) for reorientation of the magnetic anisotropy of representative near-zero magnetostrive glassy alloys.
Alloy Compositions Ea Co Fe Ni Mo B Si (10-19J) 64.0 8.0 8.0 2.0 18 0 1.1 64.0 ~.0 8.0 2.0 16 2 1.2 64.0 8.0 8.0 2.0 10 8 2.6 60.0 7.5 7.5 2.0 17 6 0.82 60.0 7.5 7.5 2.0 11 lZ 2.1 For some applications, it may be desirable or acceptable to use a material with a small positive or a small negative magnetostri~tion. Such near-zero magne-tostrictive glassy metal alloys are obtained for a, band c in the ranges of about 58 to 70, 2 to 7.5 and 0 to 8 atom percent respectively, with the provision that the sum of a, b and c ranges between 72 and 76 atom percent. The absolute value of saturation magne-tostriction l~sl of these glassy metal alloys is less than about 1 x 10-6 (i.e., the saturation magnetostric-tion ranges from about -1 x 10-6 to ~1 x 10-6, or -1 to +l microstrains). The saturation induction of these glassy alloys ranges between about 0.6 and 0.8 Tesla.
Values of ~s even closer to zero may be obtained for values of a, b and c ranging respectively from about 63 to 69, 3 to 6 and 0 to 6, with the provi-sion that the sum of a, b and c ranges between about 72 and 76 atom percent. For such preferred compositions, l~5l is less than 0.5 x 10-6. Essentially zero values of magnetostriction are obtained for values of a, b and c ranging from about 64 to 68, 4 to 5 and 0 to 6 atom percent respectively with the provision that the sum of a, b and c ranges between about 72 and 76 atom percent and also when f is between 11 and 12 atom percent and (e ~ f) is close to 24 atom percent and, accordingly, such compositions are most preferred.
The ylassy metal alloys of the invention are 12~ZZ64~
conveniently prepared by techniques readily available elsewhere; see, e.g., U.S. Patents 3,845,805, issued November 5, 1974 and 3,856,513, issued December 24, 1974O 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 23 to 26 atom percent of the total alloy composition is sufficient for glass formation, with boron ranging from about 11 to 15 atom percent and silicon ranging from about 9 to about 14 atom percent.
As noted hereinabove, a ratio Si/B close to 1 and a Si content ("f") between 11 and 12 atom percent are most favorable because they lead to higher stability and relative insensitiveness of the ~agnetostriction value (which is close to zero) to the metalloid composition.
For example, the rate of change of magnetostriction value with respect to silicon content, d~S/df, i5 close to zero for "f" between 11 and 12 atom percent while Id~s/dfl is about o.8xlo-6~at.%si near f=10 or 13 atom percent when a=67.1, b=4.5, c=3.0 and d=1.5 atom per-cent. The quantity Id~S/dfl becomes zero near f=12 atom percent and about O.lxlO-6/at.%Si near f=10 or 13 atom percent when a=67.8, b=3.7,c=3.0 and d=1.5 atom percent.
The small amount of Ni is relatively ineffec-tive to alter the magnetostriction values in the pre-sent alloy system and Co;Fe ratios essentially determine the resultant maganetostriction values. Zero magnetostriction is realized for the Co:Fe ratio of about (14 ~16.5) to 1 in the present alloy system. In the prior art glassy metal alloys such as C70.5Fe4.5B10Sil5 and Co7~Fe6B20/ the ratios are narrowly set at about 14 and 12 respectively. The above range of the Co:Fe ratio between about 14:1 to 16.5:1 and the tolerance of abol~t +0.5 atom percent z~
near f-11.5 atom percent to achieve ~s= and d~S/df =0 are advantageous from materials synthesis stand-point.
Table IV gives ac core loss ~L), exciting power (Pe) and permeability (~ ) at 0.1 Tesla induction and at 50 kHz of the near-zero magnetostrictive glassy alloys of the present invention annealed at different temperatures (Ta)~
Table IV
Examples of core loss (L), exciting power (Pe) and permeability of near-zero magnetostrictive glassy alloys annealed at different temperatures (Ta)~
Composition Co Fe Ni M~ B Si L(W/kg) Pe(Va/kg) ~ Ta(C) 67.4 4.1 3,0 1.5 12.5 11.5 5.07O 8 21300 375 15 67.1 4.4 3.0 1.5 12.5 11.5 8.3 12 14400 400 68.5 4.5 1.5 1.5 12.5 11~5 5.2 7.4 21200 400 70.0 ~.5 0 1.5 12.5 11.5 7.9 1213000 400 65.5 4.5 4~5 1.5 12.5 11.5 5.1 7.5 20900 400 6~.0 4.5 6.0 1.5 12.5 11.5 6. 89.3 16900 400 20 63.3 3.7 7.5 1.5 12.5 11.5 6. 812 13500 400 67.1 5.4 0 2.0 12.5 13 7.0 12 11000 300 *
58.4 7. 3 7.3 2.0 13 12 10 11 8200 350**
* Holding time = 5 min.;
Co~ling rate = ~0.5C/min.; ~11 = 20 Ce and Hl = 350 **Holding time = 2 hours;
Cooling rate = -0.5C/min.7 Hll = 20 Oe and Hl = 35 Oe Table V shows the effects of the annealing temperature (Ta) and annealing field (~11) applied along the circumferential cirection of the toroidal samples on the dc coercivity (Hc) and remanence (Br)~
ac coercivity (Hc~) and squareness ratio (Br/Bl), where Bl is the induction at an applied field ofl Oeat 50 kHz and ~at 50 kHz and 0.1 T induction for one of the æero magnetostrictive alloys of the present invention.
Low coercivity and high squareness ratio close to 1 at high ~requencies (e.g. 50 kHz) are desirable in some magnetic device applications such as switch-mode power supplies.
:~2~26~'Y
Table V
Ef~ects of annealing temperature (Ta) and circumferential field (Hll) on the dc coercivity (Hc) and remanence ~Br)r ac (50 kHz) coercivity (Hc') and BH loop squareness ratio (Br/Bl), and permeability at 50 kHz and Bm=o~l T for C67.4Fe4.1N13,0Mol.5B12.5Sill.5.
Annealing Conditions dc _ 50 kHz Ta (C) Hll(A/m) Hc(A/m) Br(T) Hc'(A/m) Br/Bl 350 0 0.56 0.54 24 1 15600 3501600 0.49 0.63 21 1 10000 375 0 0.49 0.38 18 1 21300 3751600 0.42 0.59 22 1 10900 400 0 0.42 0.38 17 1 20000 4001600 0.28 0.50 26 0.95 11300 425 0 0.56 0.40 21 0.89 14000 4251600 0.49 0.45 24 1 13300 4~0 0 0.56 0.39 21 0.92 14400 4401600 0.56 0.59 24 1 10600 Table VI shows the effects of the annealing time (ta) on L, Pe and ~ for one of the zero magne-tostrictive alloys of the present invention.
Table V
Effects on annealing time (ta) on core less (L), exciting power (Pe) and permeability ( ~) at induction of 0.1 Tesla and frequency of 1 kHz and 50 k~z for CO67.4Fe4.1Ni3.0Mol.sB12.sSill.s annealed at Ta=380C.
Annealing t~me 1 kHz _ 50 kHz _ _ ta (min.) L(W7~g) Pe(VA/kg) L(W/kg) Pe(VA/kg) 0.024 0.056 5~ 500 4.2 7.1 22 100 0.027 0.056 56 300 3.6 6.8 23 200 0.027 0.055 56 800 3.7 6.7 23 600 0.031 0.053 S9 000 4.9 7.2 21 700 The results set forth in Tables IV-VI above in~icate that L=4 W/kg, Pe=7 Va/kg and ~=23 000 at 0.1 T and 50 kHz can be achieved for 25-30 ~m thick zero 4~7 magnetostrictive glassy alloys of the present inven-tion. Compared with these values, a prior art crystalline nonmagnetostrictive supermalloy of the similar thickness (~5 ~m) gives L= 8 W/kg, Pe= 10 VA/kg and ~ =19 000 at 0~1 T and 50 kHz. It is clear that the properties o~ the nonmagnetostrictive glassy alloys of the present invention are superior to those of the crystalline supermalloys. Examples of amorphous alloys outside the scope of the invention are set forth in Table VII. The advantageous combination of properties provided by the alloys of the present invention cannot be achieved in the prior art nonmagnetostrictive glassy alloys with high saturation induction such as CO74Fe6B20 because their Curie temperatures are higher than the first crystallization temperatures and the heat-treatment to improve their properties are not so effective as in those with lower saturation inductions.
The above properties, achieved in the glassy alloys of the present invention, may be obtained in low induction glassy alloys of the prior art. However, these alloys of the prior art such as C31.2Fe7.sNi39.0B14Si8 tend to be magnetically unstable at relatively low tem-perature of about 150C as pointecl earlier.
Table VII shows the magnetic properties of some of the representative glassy alloys of the com-position CoaFebNicM~dBesif in which at least one of a, b, c, d, e, and f is outside the composition range defined in the present invention. The table indicates that the alloys with at least one of the constituents outside the defined ranges exhibit at least one of the following undesirable properties: ~i) The value of ¦~
is larger than lxlo-6~ (ii) The Curie temperature (~f) is higher than the crystallization temperature (TCl), which makes the post-fabrication field annealing less effective and (iii) The Curie temperature and satura-tion induction (Bs) become too low to be practicalO
-2~Z~6~7 Table VII
_ _ _ _ .
Magnetic properties of some representative CaFebNicMOdBeSif glassy alloys in which at least one of a, b, c, d, e and f is outside the range defined in the present invention.
Composition ____ ___________________ Co Fe Ni Mo B Si ~(Tesla) ~f(K) s(10~6) TCl(K) 69.4 5.6 0 0 25 0 1.0 760 ~0.0 715 64.0 8.0 8.0 2 10 8 0.97 725 +2.5 7~0 10 64.0 8.0 8.0 2 12 6 0.95 735 ~1.7 713 60.0 7.5 7.5 2 19 4 0.83 715 +1.6 760 43.8 7.3 14.~ 2 13 12 0.52 507 +2.7 817 The following examples are presented to pro-vide a more complete understanding of the invention.
The specific techniques, conditions, materials, propor-tions and reported data set forth to illustrate the principles and practice of the invention are exemplary and should not be construed as limiting the scope of the invention.
EXAMPLES
1. ample Pr aration The glassy alloys listed in Tables II-VII were rapidly quenched (about 106 K/sec) from the melt following the techniques taught by Chen and Polk in 25 U.S. Patent 3,856,513. The resulting ribbons, typi-cally 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 ductileO
2. Magnetl _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 g of ribbon. Insulated primary and secondary windings (numbering at least 10 each) were applied to the toroids. These samples were used :3 2~26~L~
-15~
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 magnetometer (Princeton Applied Research). In this case, the ribbon was cut into several small squares (approximately 2 mm x 2 mm). These were randomly oriented about their normal direction, their plane being parallel to the applied field (0 to 720 k~/m.
The saturation induction Bs (=4~MSD) was then calcu-lated 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 pri-marily to determine the crystallization temperatures.
The first or primary crystallization temperature (T
was used to compare ~he thermal stability of various glassy alloys of the present and prior art inventions.
Magnetic stability was determined from the reorientation kinetics of the magnetization, in accor-dance with the method described in Journal of Applied Physics, vol. 49, p. 6510 (1978), which method is incorporated herein by reference thereto.
Magnetostriction measurements employed metallic strain gauges (BLH Electronics), which were bonded (Eastman - 910 Cement) between two short lengtlls o~ ribbon. The ribbon axis and gauge axis were parallel. The magneto~triction was determined as a function of applied field ~rom the longitudinal strain in the parallel (~Q/Qtland perpendicular(~Q/Q)l in-plain fields, according to the formula ~ =2/3[~ ~Q/Q)I~ Q/Q)l]
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 ma~ suggest themselves to one skilled in the art, all falling within the scope o~ the invention as defined by the subjoined claims.
percent, c ranges from about 0 to 8 atom percent, d ranges from about 1 to about 2 atom percent, e ranges from about 11 to lS atom percent and f ranges from about 9 to 1~ atom percent, with the proviso that the sum of a, b and c ranges from about 72 to 76 atom percent and the sum of e and f ranges from about 23 to 26 atom percent. The glassy alloy has a value of magnetostric-tion ranging from about -1 x 10-6 to +1 x 10-6 a saturation induction ranging from about 0.6 to 0.8 Tesla, a Curie temperature ranging from about 550 to 670K
and a first crystallization temperature ranging from about 790 to 870 X.
DETAILED DESCRIPTION OF THE INVENTION
~ ___ _ In accordance with the invention, there is provided a magnetic alloy that is at least 70% glassy and which has an outstanding combination of properties, including a near-zero magnetostriction, high magnetic and thermal stability and such soft magnetic properties as high permeability, low core loss and low coercivity.
The glassy metal alloy has the composition COaFebNicModBeSif, where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom per-cent, c ranges from about 0 to 8 ato~ percent and d ranges from about 1 to about 2 atom percent, e ranges from about 11 to 15 atom percent and ~ ranges from about 9 to 14 atom percent, with ~he proviso that the sum of a, b and c ranges from about 72 to 76 atom per-cent and the sum of e and f ranges from about 23 to 26 atom percent. The glassy alloy has a value of magneto-striction ranging from about -1 x 10-6 to +1 x 10-6 and a saturation induction ranging from about 0.6 to 0.8 Tesla, Curie Temperature, ranging from 550 to 670K and the first crystallization temperature ranging from about 790 to 870 K.
The purity of the above composition is that found in normal commercial practice. However, it will be appreciated that molybdenum in the alloys of the invention may be re~laced by at least one other tran-l~ZZ64~7 sition metal element, such as tungsten, niobium, tan-talum, titanium, zirconium and hafnium, and up to about 2 atom percent of Si may be replaced by carbon, alu-minum or germanium without significantly degrading the desirable magnetic properties of these glassy alloys.
Examples of essentially zero magnetostrictive glassy metal alloys of the invention include C67.4Fe4.1Ni3.0Ml.5B12.5Sill.5, Co67.lFe4.4Ni3.0Mol.s B12.5Sill.5r C64.0Fe4.5Ni6.0M1O5B12.5Sill.5~ C67.0 Fe4.5Ni3.0M1.5B12Sil2r Co~7.oFe4.sNi3.oMol.sBl3sill and Co67.5Fe4.5Ni3.0Mol.oBl2sil2. These glassy alloys possess saturation induction between about 0.7 and 0.8 Tesla, Curie temperature between 600 and 670K, the first crystallization temperature of about 800K and excellent ductility. Some magnetic and thermal proper-ties of these and some of other near-~ero magnetostric-tive glassy alloys of the present invention are listed in Table II. These may be compared with properties listed in Table I for previously-reported glassy metal alloys of zero magnetostriction.
The activation energy (Ea) for the reorien-tation of the magnetization is listed in Table III
for some representative near-zero magnetostrictive glassy alloys. This table indicates that Si tends to increase Ea and also that Ea tends to be higher when Si/B ratio is close to 1. The higher values of Ear indicating higher magnetic stability of the system, is desired. Combining these information based Table II
and III, preferred Si content is between 9 and 14 atom percent when (Si ~ ~) is between 23 and 26 atom percent.
The presence of Mo is to increase TC1 and hence the thermal stability of the alloy system. The content of Mo beyond 2 atom percent, however, reduces the Curie temperature to a level lower than 550 K, which is undesirab]e in convention magnetic devices.
~-`` lZ~26~7 Table II
Saturation induction ~Bs), Curie temperature (a~), saturation magnetostriction ( ~s) and the first ~rystallization tempera~ure (TCl) of near-zero magnetostrictive glassy alloys.
Ccmposl ons Co Fe Ni Mo B Si B~(Tesla) ~(K) S(10-6) T ~K) ._ c 67.4 4.1 3.0 1,5 12.5 11.5 0.72 603 -0.0 798 67.1 4~4 3.0 1.5 12.5 11.5 0.75 626 +0.0 798 64.0 4.5 6.0 1.5 1205 11.5 0.70 620 -0.0 796 10 65.5 4.5 4.5 1.5 12.5 11.5 0.74 620 +0.8 799 70.0 4.5 0 1.5 12.5 11.5 0.77 649 +0.8 800 68.5 4.5 1.5 1.5 12.5 11.5 0.78 639 -0.9 801 63.3 3.7 7.5 1.5 12.5 11.5 ~.66 575 -0.7 798 67.0 4.5 3.0 1.511 13 0.72 582 +0.4 801 15 67.0 4.5 3O0 1~512 12 0.70 598 +0.0 803 67.0 4.5 3.0 1.513 11 0.74 654 +0.0 797 67.0 4.5 3.0 1.514 10 0.74 637 +0.4 800 67.8 3.7 3.0 1.511 13 0.70 558 -0.4 7g9 67.8 3.7 3.0 1.512 12 0.70 585 -0.2 804 20 67.8 3.7 3.0 1.513 11 0.70 600 -0.4 797 67.8 3.7 3.0 1.514 10 0.72 Ç23 -0.6 798 67.8 3.7 3.0 1.515 9 0.72 640 -0.6 794 66.3 5.2 3.0 1.512 12 0.72 586 +0.6 800 68.5 3.0 3.0 1.512 12 0.70 609 -0.3 796 25 69.3 2.2 3.0 1.512 12 0.70 580 -1.1 794 ~7.5 4.5 3.0 1.012 1~ 0.75 672 +0.0 810 66.6 4.4 3.0 2.012 12 0.69 610 +0.6 802 68.0 3.0 3.0 2.012 12 0.68 567 +0.8 867 62.2 5.9 5.9 2.012 12 0.69 578 +1.1 806 30 63.6 5.9 4.4 2.012 12 0.65 563 +0~8 808 65.1 5.9 3.0 2.012 12 0.68 549 +0.8 810 66.6 5.9 1.5 2.012 12 0.71 581 +1.1 808 63.0 6.0 6.0 2.012 11 0.71 673 +0.? 795 67.1 5.4 0 2.0 12.5 13 0.72 643 +0.5 820 35 58.4 7.3 7~3 2.013 12 0.62 570 +0.7 824 '7 TABLE III
Activation energy (Ea) for reorientation of the magnetic anisotropy of representative near-zero magnetostrive glassy alloys.
Alloy Compositions Ea Co Fe Ni Mo B Si (10-19J) 64.0 8.0 8.0 2.0 18 0 1.1 64.0 ~.0 8.0 2.0 16 2 1.2 64.0 8.0 8.0 2.0 10 8 2.6 60.0 7.5 7.5 2.0 17 6 0.82 60.0 7.5 7.5 2.0 11 lZ 2.1 For some applications, it may be desirable or acceptable to use a material with a small positive or a small negative magnetostri~tion. Such near-zero magne-tostrictive glassy metal alloys are obtained for a, band c in the ranges of about 58 to 70, 2 to 7.5 and 0 to 8 atom percent respectively, with the provision that the sum of a, b and c ranges between 72 and 76 atom percent. The absolute value of saturation magne-tostriction l~sl of these glassy metal alloys is less than about 1 x 10-6 (i.e., the saturation magnetostric-tion ranges from about -1 x 10-6 to ~1 x 10-6, or -1 to +l microstrains). The saturation induction of these glassy alloys ranges between about 0.6 and 0.8 Tesla.
Values of ~s even closer to zero may be obtained for values of a, b and c ranging respectively from about 63 to 69, 3 to 6 and 0 to 6, with the provi-sion that the sum of a, b and c ranges between about 72 and 76 atom percent. For such preferred compositions, l~5l is less than 0.5 x 10-6. Essentially zero values of magnetostriction are obtained for values of a, b and c ranging from about 64 to 68, 4 to 5 and 0 to 6 atom percent respectively with the provision that the sum of a, b and c ranges between about 72 and 76 atom percent and also when f is between 11 and 12 atom percent and (e ~ f) is close to 24 atom percent and, accordingly, such compositions are most preferred.
The ylassy metal alloys of the invention are 12~ZZ64~
conveniently prepared by techniques readily available elsewhere; see, e.g., U.S. Patents 3,845,805, issued November 5, 1974 and 3,856,513, issued December 24, 1974O 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 23 to 26 atom percent of the total alloy composition is sufficient for glass formation, with boron ranging from about 11 to 15 atom percent and silicon ranging from about 9 to about 14 atom percent.
As noted hereinabove, a ratio Si/B close to 1 and a Si content ("f") between 11 and 12 atom percent are most favorable because they lead to higher stability and relative insensitiveness of the ~agnetostriction value (which is close to zero) to the metalloid composition.
For example, the rate of change of magnetostriction value with respect to silicon content, d~S/df, i5 close to zero for "f" between 11 and 12 atom percent while Id~s/dfl is about o.8xlo-6~at.%si near f=10 or 13 atom percent when a=67.1, b=4.5, c=3.0 and d=1.5 atom per-cent. The quantity Id~S/dfl becomes zero near f=12 atom percent and about O.lxlO-6/at.%Si near f=10 or 13 atom percent when a=67.8, b=3.7,c=3.0 and d=1.5 atom percent.
The small amount of Ni is relatively ineffec-tive to alter the magnetostriction values in the pre-sent alloy system and Co;Fe ratios essentially determine the resultant maganetostriction values. Zero magnetostriction is realized for the Co:Fe ratio of about (14 ~16.5) to 1 in the present alloy system. In the prior art glassy metal alloys such as C70.5Fe4.5B10Sil5 and Co7~Fe6B20/ the ratios are narrowly set at about 14 and 12 respectively. The above range of the Co:Fe ratio between about 14:1 to 16.5:1 and the tolerance of abol~t +0.5 atom percent z~
near f-11.5 atom percent to achieve ~s= and d~S/df =0 are advantageous from materials synthesis stand-point.
Table IV gives ac core loss ~L), exciting power (Pe) and permeability (~ ) at 0.1 Tesla induction and at 50 kHz of the near-zero magnetostrictive glassy alloys of the present invention annealed at different temperatures (Ta)~
Table IV
Examples of core loss (L), exciting power (Pe) and permeability of near-zero magnetostrictive glassy alloys annealed at different temperatures (Ta)~
Composition Co Fe Ni M~ B Si L(W/kg) Pe(Va/kg) ~ Ta(C) 67.4 4.1 3,0 1.5 12.5 11.5 5.07O 8 21300 375 15 67.1 4.4 3.0 1.5 12.5 11.5 8.3 12 14400 400 68.5 4.5 1.5 1.5 12.5 11~5 5.2 7.4 21200 400 70.0 ~.5 0 1.5 12.5 11.5 7.9 1213000 400 65.5 4.5 4~5 1.5 12.5 11.5 5.1 7.5 20900 400 6~.0 4.5 6.0 1.5 12.5 11.5 6. 89.3 16900 400 20 63.3 3.7 7.5 1.5 12.5 11.5 6. 812 13500 400 67.1 5.4 0 2.0 12.5 13 7.0 12 11000 300 *
58.4 7. 3 7.3 2.0 13 12 10 11 8200 350**
* Holding time = 5 min.;
Co~ling rate = ~0.5C/min.; ~11 = 20 Ce and Hl = 350 **Holding time = 2 hours;
Cooling rate = -0.5C/min.7 Hll = 20 Oe and Hl = 35 Oe Table V shows the effects of the annealing temperature (Ta) and annealing field (~11) applied along the circumferential cirection of the toroidal samples on the dc coercivity (Hc) and remanence (Br)~
ac coercivity (Hc~) and squareness ratio (Br/Bl), where Bl is the induction at an applied field ofl Oeat 50 kHz and ~at 50 kHz and 0.1 T induction for one of the æero magnetostrictive alloys of the present invention.
Low coercivity and high squareness ratio close to 1 at high ~requencies (e.g. 50 kHz) are desirable in some magnetic device applications such as switch-mode power supplies.
:~2~26~'Y
Table V
Ef~ects of annealing temperature (Ta) and circumferential field (Hll) on the dc coercivity (Hc) and remanence ~Br)r ac (50 kHz) coercivity (Hc') and BH loop squareness ratio (Br/Bl), and permeability at 50 kHz and Bm=o~l T for C67.4Fe4.1N13,0Mol.5B12.5Sill.5.
Annealing Conditions dc _ 50 kHz Ta (C) Hll(A/m) Hc(A/m) Br(T) Hc'(A/m) Br/Bl 350 0 0.56 0.54 24 1 15600 3501600 0.49 0.63 21 1 10000 375 0 0.49 0.38 18 1 21300 3751600 0.42 0.59 22 1 10900 400 0 0.42 0.38 17 1 20000 4001600 0.28 0.50 26 0.95 11300 425 0 0.56 0.40 21 0.89 14000 4251600 0.49 0.45 24 1 13300 4~0 0 0.56 0.39 21 0.92 14400 4401600 0.56 0.59 24 1 10600 Table VI shows the effects of the annealing time (ta) on L, Pe and ~ for one of the zero magne-tostrictive alloys of the present invention.
Table V
Effects on annealing time (ta) on core less (L), exciting power (Pe) and permeability ( ~) at induction of 0.1 Tesla and frequency of 1 kHz and 50 k~z for CO67.4Fe4.1Ni3.0Mol.sB12.sSill.s annealed at Ta=380C.
Annealing t~me 1 kHz _ 50 kHz _ _ ta (min.) L(W7~g) Pe(VA/kg) L(W/kg) Pe(VA/kg) 0.024 0.056 5~ 500 4.2 7.1 22 100 0.027 0.056 56 300 3.6 6.8 23 200 0.027 0.055 56 800 3.7 6.7 23 600 0.031 0.053 S9 000 4.9 7.2 21 700 The results set forth in Tables IV-VI above in~icate that L=4 W/kg, Pe=7 Va/kg and ~=23 000 at 0.1 T and 50 kHz can be achieved for 25-30 ~m thick zero 4~7 magnetostrictive glassy alloys of the present inven-tion. Compared with these values, a prior art crystalline nonmagnetostrictive supermalloy of the similar thickness (~5 ~m) gives L= 8 W/kg, Pe= 10 VA/kg and ~ =19 000 at 0~1 T and 50 kHz. It is clear that the properties o~ the nonmagnetostrictive glassy alloys of the present invention are superior to those of the crystalline supermalloys. Examples of amorphous alloys outside the scope of the invention are set forth in Table VII. The advantageous combination of properties provided by the alloys of the present invention cannot be achieved in the prior art nonmagnetostrictive glassy alloys with high saturation induction such as CO74Fe6B20 because their Curie temperatures are higher than the first crystallization temperatures and the heat-treatment to improve their properties are not so effective as in those with lower saturation inductions.
The above properties, achieved in the glassy alloys of the present invention, may be obtained in low induction glassy alloys of the prior art. However, these alloys of the prior art such as C31.2Fe7.sNi39.0B14Si8 tend to be magnetically unstable at relatively low tem-perature of about 150C as pointecl earlier.
Table VII shows the magnetic properties of some of the representative glassy alloys of the com-position CoaFebNicM~dBesif in which at least one of a, b, c, d, e, and f is outside the composition range defined in the present invention. The table indicates that the alloys with at least one of the constituents outside the defined ranges exhibit at least one of the following undesirable properties: ~i) The value of ¦~
is larger than lxlo-6~ (ii) The Curie temperature (~f) is higher than the crystallization temperature (TCl), which makes the post-fabrication field annealing less effective and (iii) The Curie temperature and satura-tion induction (Bs) become too low to be practicalO
-2~Z~6~7 Table VII
_ _ _ _ .
Magnetic properties of some representative CaFebNicMOdBeSif glassy alloys in which at least one of a, b, c, d, e and f is outside the range defined in the present invention.
Composition ____ ___________________ Co Fe Ni Mo B Si ~(Tesla) ~f(K) s(10~6) TCl(K) 69.4 5.6 0 0 25 0 1.0 760 ~0.0 715 64.0 8.0 8.0 2 10 8 0.97 725 +2.5 7~0 10 64.0 8.0 8.0 2 12 6 0.95 735 ~1.7 713 60.0 7.5 7.5 2 19 4 0.83 715 +1.6 760 43.8 7.3 14.~ 2 13 12 0.52 507 +2.7 817 The following examples are presented to pro-vide a more complete understanding of the invention.
The specific techniques, conditions, materials, propor-tions and reported data set forth to illustrate the principles and practice of the invention are exemplary and should not be construed as limiting the scope of the invention.
EXAMPLES
1. ample Pr aration The glassy alloys listed in Tables II-VII were rapidly quenched (about 106 K/sec) from the melt following the techniques taught by Chen and Polk in 25 U.S. Patent 3,856,513. The resulting ribbons, typi-cally 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 ductileO
2. Magnetl _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 g of ribbon. Insulated primary and secondary windings (numbering at least 10 each) were applied to the toroids. These samples were used :3 2~26~L~
-15~
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 magnetometer (Princeton Applied Research). In this case, the ribbon was cut into several small squares (approximately 2 mm x 2 mm). These were randomly oriented about their normal direction, their plane being parallel to the applied field (0 to 720 k~/m.
The saturation induction Bs (=4~MSD) was then calcu-lated 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 pri-marily to determine the crystallization temperatures.
The first or primary crystallization temperature (T
was used to compare ~he thermal stability of various glassy alloys of the present and prior art inventions.
Magnetic stability was determined from the reorientation kinetics of the magnetization, in accor-dance with the method described in Journal of Applied Physics, vol. 49, p. 6510 (1978), which method is incorporated herein by reference thereto.
Magnetostriction measurements employed metallic strain gauges (BLH Electronics), which were bonded (Eastman - 910 Cement) between two short lengtlls o~ ribbon. The ribbon axis and gauge axis were parallel. The magneto~triction was determined as a function of applied field ~rom the longitudinal strain in the parallel (~Q/Qtland perpendicular(~Q/Q)l in-plain fields, according to the formula ~ =2/3[~ ~Q/Q)I~ Q/Q)l]
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 ma~ suggest themselves to one skilled in the art, all falling within the scope o~ the invention as defined by the subjoined claims.
Claims (9)
1. A magnetic alloy that is at least 70%
glassy, having the formula CoaFebNicModBesif where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom percent, c rangaes from O to 8 atom percent, d ranges from about 1 to 2 atom percent, e ranges from about 11 to 15 atom percent and f ranges from about 9 to 14 atom percent with the proviso that the sum of a, b and c ranges from about 72 to 76 atom percent and the sum of e and f ranges from about 23 to 26 atom percent, said alloy having a value of magne-tostriction between -lxlO-6 and +1xlO-6.
glassy, having the formula CoaFebNicModBesif where a ranges from about 58 to 70 atom percent, b ranges from about 2 to 7.5 atom percent, c rangaes from O to 8 atom percent, d ranges from about 1 to 2 atom percent, e ranges from about 11 to 15 atom percent and f ranges from about 9 to 14 atom percent with the proviso that the sum of a, b and c ranges from about 72 to 76 atom percent and the sum of e and f ranges from about 23 to 26 atom percent, said alloy having a value of magne-tostriction between -lxlO-6 and +1xlO-6.
2. The magnetic alloy of claim 1 in which a ranges from about 63 to 69 atom percent, b ranges from about 3 to 6 atom percent and c ranges from about O to 6 atom percent.
3. The magnetic alloy of claim 1 in which a ranges from about 64 to 68 atom percent, b ranges from 4 to 5 atom percent and c ranges from 0 to 6 atom per-cent when f is between 11 and 12 atom percent and the sum of e and f is near 24 atom percent.
4. The magnetic alloy of claim 3 having the formula Co67.Fe4.1Ni3.0Mo1.5B12.5Si11.5.
5. The magnetic alloy of claim 3 having the formula Co67.lFe4,4Ni3,0Mol.5Bl2.5si~
6. The magnetic alloy of claim 3 having the formula co64.oFe4osNi6~oMol.5b 12si11.5
7. The magnetic alloy of claim 3 having the formula Co67.oFe4.sNi3.oMo1.sBl2si12.
8. The magnetic alloy of claim 3 having the formula Co67.oFe4.sNi3.oMol.sBl3sill-
9. The magnetic alloy of claim 3 having the formula co67. 5fe4.5ni3.oMo1.oB12Si12.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34041382A | 1982-01-18 | 1982-01-18 | |
| US340,413 | 1982-01-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222647A true CA1222647A (en) | 1987-06-09 |
Family
ID=23333255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000418542A Expired CA1222647A (en) | 1982-01-18 | 1982-12-23 | Near-zero magnetostrictive glassy metal alloys with high magnetic and thermal stability |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0084138B1 (en) |
| JP (1) | JPS58123851A (en) |
| CA (1) | CA1222647A (en) |
| DE (1) | DE3275492D1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0643627B2 (en) * | 1985-07-26 | 1994-06-08 | ユニチカ株式会社 | Amorphous metal wire |
| EP0240600B1 (en) * | 1986-01-08 | 1992-05-13 | AlliedSignal Inc. | Glassy metal alloys with perminvar characteristics |
| US4938267A (en) * | 1986-01-08 | 1990-07-03 | Allied-Signal Inc. | Glassy metal alloys with perminvar characteristics |
| WO1988003699A1 (en) * | 1986-11-03 | 1988-05-19 | Allied Corporation | Near-zero magnetostrictive glassy metal alloys for high frequency applications |
| DE3856334T2 (en) * | 1987-08-07 | 1999-11-04 | Mitsui Chemicals, Inc. | Device for evaluating the insulation condition |
| EP0303324A1 (en) * | 1987-08-10 | 1989-02-15 | Koninklijke Philips Electronics N.V. | Magnetic material, method of manufacturing this material and a magnetic head provided with this material |
| DE3900946A1 (en) * | 1989-01-14 | 1990-07-26 | Vacuumschmelze Gmbh | MAGNETIC CORE FOR AN INTERFACE TRANSMITTER |
| KR100339315B1 (en) * | 1996-09-17 | 2002-06-03 | 베르너 하르바우어; 볼프-디이터 프라이부르크 | Pulse transformer for line interfaces operating according to the echo compensation principle and method for producing a toroidal tape core comprised in pulse a transformer for line interfaces |
| US6432226B2 (en) * | 1999-04-12 | 2002-08-13 | Alliedsignal Inc. | Magnetic glassy alloys for high frequency applications |
| EP2821183B1 (en) | 2013-07-05 | 2017-06-21 | Black & Decker Inc. | Hammer Drill |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL182182C (en) * | 1974-11-29 | 1988-01-18 | Allied Chem | DEVICE WITH AMORPHIC METAL ALLOY. |
| US4056411A (en) * | 1976-05-14 | 1977-11-01 | Ho Sou Chen | Method of making magnetic devices including amorphous alloys |
| US4038073A (en) * | 1976-03-01 | 1977-07-26 | Allied Chemical Corporation | Near-zero magnetostrictive glassy metal alloys with high saturation induction |
| US4150981A (en) * | 1977-08-15 | 1979-04-24 | Allied Chemical Corporation | Glassy alloys containing cobalt, nickel and iron having near-zero magnetostriction and high saturation induction |
-
1982
- 1982-12-17 DE DE8282111754T patent/DE3275492D1/en not_active Expired
- 1982-12-17 EP EP19820111754 patent/EP0084138B1/en not_active Expired
- 1982-12-23 CA CA000418542A patent/CA1222647A/en not_active Expired
-
1983
- 1983-01-18 JP JP58006529A patent/JPS58123851A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0084138A3 (en) | 1985-08-21 |
| EP0084138A2 (en) | 1983-07-27 |
| DE3275492D1 (en) | 1987-04-02 |
| JPH0338334B2 (en) | 1991-06-10 |
| EP0084138B1 (en) | 1987-02-25 |
| JPS58123851A (en) | 1983-07-23 |
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