Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
  • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
  • H01F41/0206—Manufacturing of magnetic cores by mechanical means
  • H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
• • 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
  • H01F1/15333—Amorphous metallic alloys, e.g. glassy metals containing nanocrystallites, e.g. obtained by annealing
• • 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
  • H01F1/15341—Preparation processes therefor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S977/00—Nanotechnology
  • Y10S977/70—Nanostructure
  • Y10S977/832—Nanostructure having specified property, e.g. lattice-constant, thermal expansion coefficient
  • Y10S977/838—Magnetic property of nanomaterial

Definitions

• the present invention relates to nanocrystalline magnetic materials intended, in particular, for the manufacture of magnetic circuits for apparatus electric.
• Nanocrystalline magnetic materials are well known and have been described, in particular, in European patent applications EP 0 271 657 and EP 0 299 498. These are iron-based alloys, containing more than 60 at% (atoms%) of iron, copper, silicon, boron, and possibly at least one element taken among niobium, tungsten, tantalum, zirconium, hafnium, titanium and molybdenum, cast in the form of amorphous ribbons and then subjected to a treatment which causes extremely fine crystallization (the crystals have less 100 nanometers in diameter). These materials have magnetic properties particularly suitable for the manufacture of soft magnetic cores for electrotechnical devices such as earth leakage circuit breakers.
• hysteresis (Br / Bm ⁇ 0.5), i.e. a cycle of coated hysteresis (Br / Bm ⁇ 0.3); Br / Bm being the ratio of remanent magnetic induction to magnetic induction maximum.
• Round hysteresis cycles are obtained when treatment thermal consists of a simple annealing at a temperature of about 500 ° C.
• the lying hysteresis cycles are obtained when the heat treatment involves at least one annealing under magnetic field, this annealing being able to be the annealing intended to cause the formation of nanocrystals.
• Materials with a round hysteresis cycle may exhibit very high magnetic permeability, even higher than that of alloys of the type Classic permalloys. This very high magnetic permeability makes them, a priori, particularly suitable for the manufacture of magnetic cores for circuit breakers AC class differentials, i.e. sensitive to fault currents alternative. However, for such use to be possible, it is necessary that the magnetic properties of the nuclei are sufficiently reproducible to that mass production is satisfactory.
• an amorphous magnetic alloy ribbon capable of being used to acquire a nanocrystalline structure.
• the toroids thus obtained are then annealed in order to cause the formation of nanocrystals and, as a result, their confer the desired magnetic properties.
• the annealing temperature which located around 500 ° C, is chosen so that the magnetic permeability of the alloy is maximum.
• the magnetic cores thus obtained are intended for receive windings which generate mechanical stresses which deteriorate the magnetic properties of the nuclei.
• the toroids are arranged in protective boxes with the interior of which they are wedged for example by foam rings.
• this wedging of the toroids in their casing induces, by itself, low stresses which are detrimental to the excellent magnetic properties developed on the nucleus.
• the use of a protective case although effective not always sufficient, and, after winding, the properties of the devices obtained by industrial production are degraded and too dispersed to be even acceptable for the intended use.
• the object of the present invention is to remedy these drawbacks by proposing a means for mass production of magnetic cores of material nanocrystalline, having both magnetic permeability (relative permeability impedance at 50 Hz maximum) greater than 400,000 and a round hysteresis cycle, so that the dispersion of their magnetic properties is compatible with the use for mass production of class GFCIs AC.
• This process applies to all soft magnetic alloys based on iron capable of exhibiting a nanocrystalline structure, and more particularly to alloys whose chemical composition comprises, in% atoms: Fe ⁇ 60% 0.5% ⁇ Cu ⁇ 1.5% 5% ⁇ B ⁇ 14% 5% ⁇ Si + B ⁇ 30% 2% ⁇ Nb ⁇ 4%
• the chemical composition of the alloy may also include low contents of impurities provided by raw materials or resulting from development.
• the amorphous ribbon is obtained in a manner known per se by solidification very fast liquid alloy.
• Magnetic core blanks are fabricated also in a manner known per se by winding the ribbon on a mandrel, cutting it and fixing its end with a welding point, in order to obtain small tori of rectangular section.
• the blanks must then be subjected to a annealing treatment to precipitate nanocrystals in the amorphous matrix of size less than 100 nanometers. This very fine crystallization makes it possible to obtain desired magnetic properties, and thus transforming the core blank magnetic in magnetic core.
• the inventors having unexpectedly found that the effect of the conditions annealing on the magnetic properties of the nuclei depended not only on the chemical composition of the alloy, but also, and not very controllably, special manufacturing conditions for each ribbon taken individually, before to carry out the annealing, the temperature Tm which determines, for an annealing of given duration, at the maximum magnetic permeability that it is possible to obtain on a torus made with the ribbon.
• This temperature Tm is specific to each ribbon, it is therefore determined for each ribbon by tests that a person skilled in the art can do.
• the annealing is carried out at a temperature T between Tm + 10 ° C and Tm + 50 ° C, and preferably between Tm + 20 ° C and Tm + 40 ° C, for a time between 0.1 and 10 hours, and, from preferably between 0.5 and 5 hours.
• Temperature and time are two setting parameters for annealing partially equivalent. However, variations in the annealing temperature have a much stronger effect than variations in the duration of annealing, in particular at the ends of the admissible annealing temperature range. Also, the temperature is a relatively coarse adjustment parameter of the conditions of processing, time is a fine adjustment parameter.
• the specific conditions of treatment are determined based on the intended use for the magnetic core.
• each core is placed in a box protector, in which it is wedged, for example, with foam washers.
• each core can be coated in a resin.
• the annealing temperature is not equal to Tm, the magnetic permeability of nuclei is not maximum. However, the inventors have found that in doing so, one could obtain a sufficiently reliable permeability magnetic greater than 400,000. They also found that the nuclei obtained magnets were well suited for mass production of circuit breakers differentials, and, in particular, they were less sensitive to the effect of constraints winding.
• Lot A was annealed at 505 ° C (Tm + 5 ° C) for 1 hour, in accordance with the prior art, lot B was annealed at 530 ° C (Tm + 30 ° C) for 3 hours, in accordance with the prior art to the invention, and batch C was annealed at 555 ° C (Tm + 55 ° C) for 3 hours, for comparison.
• the mean and standard deviation of the magnetic permeability values were determined for each of the batches, on the one hand for the naked nuclei, and on the other hand for the cased nuclei, that is to say, subjected to light stresses due to the setting of the torus in its case.
• lots B and C are more lower than the standard deviation of the magnetic permeability values of the nuclei magnetic, in case or not, of lot A.
• the difference between lots A and B results that the magnetic cores in lot B are less sensitive to stresses mechanical than the magnetic cores in lot A.
• the magnetic cores in lot C are a priori less sensitive to mechanical stresses than cores magnetic of batch B, but have permeabilities incompatible with the application.
• the dispersion of the magnetic properties of the nuclei of batch B is lower than that of the nuclei of batch A, and because the sensitivity of these properties under mechanical stress is lower for lot B than for lot A, after winding the magnetic cores of lot B are well suited to use in class AC residual current devices, while the cores of the lot A are not reliably so.
• the magnetic cores of lot C although having theoretically lower sensitivity to mechanical stresses than lot B cores, are not suitable for use in circuit breakers differentials, especially because they have insufficient magnetic permeability.
• Such cores can be made by performing at least annealing under magnetic field.
• Annealing under magnetic field can be either the annealing which has just been described and which is intended to cause the precipitation of nanocrystals, i.e. an additional annealing carried out between 350 and 550 ° C.
• the cores thus obtained have, in the same way, a sensitivity to the stresses very low mechanical properties, which increases the reliability of mass production.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Inorganic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Soft Magnetic Materials (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
• Heat Treatment Of Articles (AREA)
• Hard Magnetic Materials (AREA)
• Thin Magnetic Films (AREA)
• Compounds Of Iron (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=9496996

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Cited By (1)

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Citations (4)

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• 1996
  • 1996-10-25 FR FR9612996A patent/FR2755292B1/fr not_active Expired - Fee Related
• 1997
  • 1997-10-13 DE DE69708828T patent/DE69708828T2/de not_active Expired - Fee Related
  • 1997-10-13 AT AT97402396T patent/ATE210332T1/de not_active IP Right Cessation
  • 1997-10-13 EP EP97402396A patent/EP0844628B1/de not_active Expired - Lifetime
  • 1997-10-13 ES ES97402396T patent/ES2166516T3/es not_active Expired - Lifetime
  • 1997-10-16 AU AU41029/97A patent/AU715096B2/en not_active Ceased
  • 1997-10-17 TW TW086115296A patent/TW354842B/zh active
  • 1997-10-20 KR KR1019970053787A patent/KR19980032982A/ko active IP Right Grant
  • 1997-10-20 ZA ZA9709359A patent/ZA979359B/xx unknown
  • 1997-10-21 HU HU9701672A patent/HU221412B1/hu not_active IP Right Cessation
  • 1997-10-22 SK SK1445-97A patent/SK284075B6/sk unknown
  • 1997-10-23 CZ CZ19973372A patent/CZ293222B6/cs not_active IP Right Cessation
  • 1997-10-23 TR TR97/01235A patent/TR199701235A2/xx unknown
  • 1997-10-24 PL PL97322808A patent/PL184054B1/pl not_active IP Right Cessation
  • 1997-10-24 CN CNB97125284XA patent/CN1134033C/zh not_active Expired - Fee Related
  • 1997-10-27 US US08/957,937 patent/US5922143A/en not_active Expired - Fee Related
  • 1997-10-27 JP JP9311379A patent/JPH10130797A/ja not_active Withdrawn
• 1998
  • 1998-12-02 HK HK98112657A patent/HK1011578A1/xx not_active IP Right Cessation

Patent Citations (4)

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