Metal treatment – Stock – Magnetic
Reexamination Certificate
1998-06-25
2001-08-07
King, Roy (Department: 1742)
Metal treatment
Stock
Magnetic
C148S301000, C148S302000, C148S303000, C148S304000, C428S379000
Reexamination Certificate
active
06270591
ABSTRACT:
TECHNICAL FIELD
The invention refers to amorphous and nanocrystalline magnetic glass-covered wires with applications in electrotechnics and electronics and to a process for their production.
BACKGROUND ART
There are known ribbon and wire shaped amorphous magnetic materials obtained by rapid quenching from the melt and nanocrystalline magnetic materials obtained by thermal treatment of amorphous ones with adequate compositions (U.S. Pat. No. 4,501,316/Feb. 26, 1985 and U.S. Pat. No. 4,523,626/Jun. 18, 1985). Thus, amorphous magnetic wires with diameters ranging from 60 &mgr;m . . . 180 &mgr;m are obtained by the in-rotating-water spinning method and nanocrystalline magnetic wires are obtained by controlled thermal treatments of the above mentioned amorphous ones with adequate compositions. The disadvantage of these wires consists in the fact that they can not be obtained directly from the melt in amorphous state with diameters less than 60 &mgr;m. Amorphous magnetic wires having diameters of minimum 30 &mgr;m are obtained by successive cold-drawings of the above mentioned amorphous magnetic wires followed by stress relief thermal treatments. The disadvantage of these wires consists in the fact that by repeated drawings and annealing stages they can be obtained amorphous magnetic wires having no less than 30 &mgr;m in diameter and also in the fact that their magnetic and mechanical properties are unfavorably affected by the mechanical treatments.
There are also known metallic glass-covered wires in crystalline state as well as some glass-covered amorphous alloys obtained by the glass-coated melt spinning method (T. Goto, T. Toyama, “The preparation of ductile high strength Fe-base filaments using the methods of glass-coated melt spinning”,
Journal of Materials Science
20(1985) pp. 1883-1888). The disadvantage of these wires consists in the fact that they do not present appropriate magnetic properties and behavior for applications in electronics and electrotechnics to achieve magnetic sensors and actuators, but only properties that makes them useful as metallic catalysts, composite materials, electrical conductors.
There are known amorphous magnetic glass-covered wires having the compositions Fe
65
B
15
Si
15
C
15
, Fe
60
B
15
Si
15
Cr
10
and Fe
40
Ni
40
P
14
B
6
(H. Chiriac et al., “Magnetic behavior of the amorphous wires covered by glass”,
Journal of Applied Physics
75 (10), (1994), pp. 6949-6951) with diameters of the metallic core ranging between 5 and 30 &mgr;m, coercive fields between 239 and 462 A/m, and magnetization between 0.16 to 0.32T. It is also mentioned a method for their obtaining based on the Taylor method, indicating as steps: the sealing of the glass tube, the heating of the seal and the drawing of a fibre from the heated end.
There are also known amorphous glass-covered wires of compositions (Fe
80
Co
20
)
75
B
15
Si
10
and Fe
65
B
15
Si
15
C
15
like in the above mentioned in Prior Art (A. P. Zhukov et al., “The remagnetization process in thin and ultra-thin Fe-rich amorphous wires”,
JMMM
15(1995), pp. 132-138) having diameters of the metallic core of 10 and 15 &mgr;m respectively, thickness of the glass-cover of 2.5 &mgr;m, and coercive fields of 65 and 140 A/m respectively.
DISCLOSURE OF INVENTION
Technical problem resolved by this invention consists in the obtaining, directly by rapid quenching from the melt, of the glass-covered magnetic amorphous wires having controlled dimensional and compositional characteristics and in the obtaining, by thermal treatments, of the nanocrystalline magnetic wires with adequate magnetic properties for different applications categories.
The amorphous magnetic wires, according to the invention, are characterized in the fact that they consist in an amorphous metallic inner core with diameters ranging between 1 &mgr;m and 50 &mgr;m and a glass cover in the shape of a glass coat with a thickness ranging between 0.5 &mgr;m and 20 &mgr;m, the metallic core having compositions chosen so to allow to obtain wires in amorphous state, at cooling rates that can be technically obtained and with adequate magnetic properties for different applications categories. The amorphous magnetic wires, according to the invention, consists of an amorphous metallic inner core of compositions based on transition metals (Fe, Co, and/or Ni) 60 . . . 80 atomic %, 40 . . . 15 atomic % metalloid (B, Si, C and/or P) as well as 25 atomic % or less additional metals such as Cr, Ta, Nb, V, Cu, Al, Mo, Mn, W, Zr, Hf, having diameters ranging between 1 and 50 &mgr;m and a glass cover with thickness ranging between 0.5 and 20 &mgr;m. The amount of the transition metals and metalloids is chosen so to obtain alloys with high saturation magnetization, positive, negative or nearly zero magnetostriction, coercive field and magnetic permeability having adequate values in function of the requested applications. The total amount and the number of the additional elements are chosen so to facilitate the amorphism-forming ability.
For applications in sensors and transducers in which a rapid variation of the magnetization as function of external factors (magnetic field, tensile stress, torsion) is required, they are adequate amorphous magnetic glass-covered wires, according to the invention, having high positive magnetostriction, 5 up to 25 &mgr;m diameter of the metallic core and 1 up to 15 &mgr;m thickness of the glass cover, of compositions based on Fe containing 20 atomic % or less Si, 7 up to 35 atomic % B and 25 atomic % or less from one or more metals selected from the group Co, Ni, Cr, Ta, Nb, V, Cu, Al, Mo, Mn, W, Zr, Hf.
For applications in sensors and transducers that require a variation of the magnetization as function of external factors (magnetic field, tensile stress, torsion), whose value must be controlled with a high sensitivity, as well as for applications based on the giant magneto-impedance effect involving high values of the magnetic permeability and reduced values of the coercive field, they are adequate amorphous magnetic glass-covered wires, according to the invention, having negative or almost zero magnetostriction, with diameters of the metallic core ranging between 5 and 25 &mgr;m and thickness of the glass cover ranging between 1 and 15 &mgr;m of compositions based on Co containing 20 atomic % or less Si, 7 up to 35 atomic % B and 25 atomic % or less from one or more metals selected from the group Fe, Ni, Cr, Ta, Nb, V, Cu, Al, Mo, Mn, W, Zr, Hf.
For applications as minitransformers and inductive coils, that implies high values of the saturation magnetization and of the magnetic permeability they are adequate nanocrystalline magnetic glass-covered wires according to the invention with diameters of the metallic core ranging between 5 and 25 &mgr;m and thickness of the glass cover ranging between 1 and 15 &mgr;m of compositions based on Fe containing 20 atomic % or less is, 7 up to 35 atomic % B and 25 atomic % or less from one or more metals selected from the group Cu, Nb, V, Ta, W, Zr, Hf.
For applications in devices working on the base of the correlation between the magnetic properties of the amorphous metallic core with positive or nearly zero magnetostriction or of the nanocrystalline metallic core having nearly zero magnetostriction and the optical properties of the glass cover, properties that are related to the optical transmission of the information, they are adequate amorphous and nanocrystalline glass-covered wires according to the invention, with diameters of the metallic core ranging between 10 and 20 &mgr;m and thickness of the glass cover ranging between 10 and 20 &mgr;m of compositions based on Fe or Co containing 20 atomic % or less is, 7 up to 35 atomic % B and 25 atomic % or less from one or more metals selected from the group Ni, Cr, Ta, Nb, V, Cu, Al, Mo, Mn, W, Zr, Hf.
The process of producing amorphous magnetic glass-covered wires, according to the invention, allows to obtain wires with the above mentioned dimensional and compositional characteristics directly by rapid quenching from the melt and consists in melti
Barariu Firuta
Chiriac Horia
Ovari Adrian Tibor
Pop Gheorghe
Kasper Horst M.
King Roy
McGuthry-Banks Tima
LandOfFree
Amorphous and nanocrystalline glass-covered wires does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Amorphous and nanocrystalline glass-covered wires, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Amorphous and nanocrystalline glass-covered wires will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2466773