EP0435885B1 - Alliages de verres metalliques pour systemes de surveillance d'objets a cibles incorporees utilisant la resonance mecanique de la cible - Google Patents

Alliages de verres metalliques pour systemes de surveillance d'objets a cibles incorporees utilisant la resonance mecanique de la cible Download PDF

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Publication number
EP0435885B1
EP0435885B1 EP89909913A EP89909913A EP0435885B1 EP 0435885 B1 EP0435885 B1 EP 0435885B1 EP 89909913 A EP89909913 A EP 89909913A EP 89909913 A EP89909913 A EP 89909913A EP 0435885 B1 EP0435885 B1 EP 0435885B1
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Prior art keywords
ranges
zero
alloys
ring down
khz
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Expired - Lifetime
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EP89909913A
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German (de)
English (en)
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EP0435885A1 (fr
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V. R. V. Ramanan
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Honeywell International Inc
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AlliedSignal Inc
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2408—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using ferromagnetic tags
    • G08B13/2411—Tag deactivation
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2437—Tag layered structure, processes for making layered tags
    • G08B13/2442—Tag materials and material properties thereof, e.g. magnetic material details
    • 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
    • H01F1/15308—Amorphous metallic alloys, e.g. glassy metals based on Fe/Ni

Definitions

  • This invention relates to metallic glass alloys; and more particularly to metallic glass alloys suited for use in mechanically resonant targets of article surveillance systems.
  • An essential component of all surveillance systems is a sensing unit, or "target", that is attached to the object to be detected.
  • Other components of the system include a transmitter and a receiver that are suitably disposed in an "interrogation" zone.
  • the functional part of the target responds to a signal from the transmitter, which response is detected in the receiver.
  • the information contained in the response signal is then processed for actions appropriate to the application: denial of access, triggering of an alarm, and the like.
  • the target in such systems is a strip, or a plurality of strips, of known length of a ferromagnetic material, packaged with a harder ferromagnet (material with a higher coercivity) that provides a biasing field to establish peak magnetomechanical coupling.
  • the ferromagnetic material is preferably a metallic glass alloy ribbon, since the efficiency of magnetomechanical coupling in these alloys is very high.
  • the mechanical resonance frequency of the target material is dictated essentially by the length of the alloy ribbon and the biasing field strength. When an interrogating signal tuned to this resonance frequency is encountered, the target material responds with a large signal field which is detected by the receiver. The large signal field is attributable to an enhanced magnetic permeability of the target material at the resonance frequency.
  • the target material is excited into oscillations by pulses, or bursts, of signal at its resonance frequency generated by the transmitter.
  • the exciting pulse When the exciting pulse is over, the target material will undergo damped oscillations at its resonance frequency, i.e., the target material "rings down” following the termination of the exciting pulse.
  • the receiver “listens” to the response signal during this ring down period.
  • the surveillance system is relatively immune to interferences from various radiated or power line conducted sources and, therefore, the potential for false alarms is essentially eliminated.
  • the present invention provides magnetic alloys that are at least about 70% glassy and are characterized by long ring down times in resonance target applications. Such alloys evidence a low rate of damping of resonant oscillations, following the termination of an exciting pulse.
  • the glassy-metal alloys of the invention have a composition described by the formula Fe a Ni b M c B d Si e C f , where M is one of molybdenum and chromium, "a” - “f” are in atom percent, "a” ranges from about 39 to about 41, “b” ranges from about 37 to about 39, “c” ranges from 0 to about 3, “d” ranges from about 17 to about 19, and “e” and “f” range from 0 to about 2, with the provisos that (i) only one of "c", "e” and “f” can be zero, (ii) "e” cannot be zero if "f” is not zero, and (iii) "f” can be zero only when M is Cr
  • Ribbons of these alloys when mechanically resonant at frequencies ranging from about 55 kHz to about 60 kHz, evidence ring down times of at least about 3 ms.
  • ribbons of these alloys when mechanically resonant at frequencies ranging from about 21 kHz to about 25 kHz, evidence ring down times of at least about 7 ms.
  • the metallic glasses of this invention are especially suitable for use as the active elements in targets associated with surveillance systems that employ resonance frequency excitation and detection modes. Other uses may be found in special magnetic amplifiers, relay cores, ground fault interrupters and the like.
  • the glassy metal alloys of the invention have a composition described by the formula Fe a Ni b M c B d Si e C f , where M is one of molybdenum and chromium, "a" - “f” are in atom percent, “a” ranges from about 39 to about 41, “b” ranges from about 37 to about 39, “c” ranges from 0 to about 3, “d” ranges from about 17 to about 19, and “e” and “f” range from 0 to about 2, with the provisos that (i) only one of "c", “e” and “f” can be zero, (ii) "e” cannot be zero if "f” is not zero, and (iii) "f” can be zero only when M is Cr.
  • Ribbons having mechanical resonances in the range from about 55 kHz to about 60 kHz are preferred. Such ribbons are short enough to be used as disposable target materials. In addition, the resonance signals of such ribbons are well separated from the audio and commercial radio frequency ranges.
  • alloys of the present invention offer the advantageous combination of long ring down times and economy in production of usable ribbon.
  • such longer time intervals provide an additional, and advantageous, feature in the detection system in that the receiver may "listen" to the sample response more than once during the same ring down cycle, for confirmation purposes.
  • metallic glasses of the invention include Fe40Ni38Mo2B18Si1C1, Fe40N38Mo3B18Si 0.5 C 0.5 , Fe40Ni38Mo1B18Si 1.5 C 1.5 , Fe40Ni38Mo 2.5 B 17.5 Si1C1, Fe40Ni38Mo 1.5 B 18.5 Si1C1, Fe40Ni38Mo3B17Si1C1, Fe40Ni38Cr2B18Si2, and Fe40Ni38B18Si2C2, where all numbers are in atomic percent.
  • the target material is exposed to a burst of exciting signal of constant amplitude, referred to as the exciting pulse, tuned to the frequency of mechanical resonance of the target material.
  • the exciting pulse is outlined in thick dashed lines in the Figure, and the peak-to-peak amplitude of the pulse is denoted by the quantity V0.
  • V0 the peak-to-peak amplitude of the pulse
  • the physical principle governing this resonance may be summarized as follows: When a ferromagnetic material is subjected to a magnetizing magnetic field, it experiences a change in length.
  • the fractional change in length, over the original length, of the material is referred to as magnetostriction and denoted by the symbol ⁇ .
  • a positive signature is assigned to ⁇ if an elongation occurs parallel to the magnetizing magnetic field.
  • the ribbon When a ribbon of a material with a positive magnetostriction is subjected to a sinusoidally varying external field, applied along its length, the ribbon will undergo periodic changes in length, i.e., the ribbon will be driven into oscillations.
  • the external field may be generated, for example, by a solenoid carrying a sinusoidally varying current.
  • the frequency of the ribbon oscillations will be twice that of the driving field, since the magnetostriction is insensitive to the direction of the driving field at any given instant. In other words, as long as the absolute magnitude of the driving field is non-zero, there will be a change in the ribbon length.
  • Magnetomechanical resonance occurs when the frequency of the driving field is one-half of f r , the mechanical resonance frequency of the ribbon.
  • the biasing field serves other purposes as well.
  • Magnetostrictive effects are observed in a ferromagnetic material only when the magnetization of the material proceeds through domain rotation. No magnetostriction is observed when motion of plane parallel domain walls is the mechanism for magnetization.
  • the biasing field places the material at, or beyond, the "knee" of hysteresis loop of the material, in which magnetic state the motion of plane parallel walls has been expended, and further magnetization of the sample occurs mainly by domain rotation. The efficiency of magnetomechanical response from the material has thus been improved. It is also well understood in the art that a biasing field serves to change the effective value for E in a ferromagnetic material so that the mechanical resonance frequency of the material may be modified by a suitable choice of strength for the biasing field.
  • a ribbon of a positively magnetostrictive ferromagnetic material when exposed to a driving ac magnetic field in the presence of a dc biasing field, will oscillate at the frequency of the driving ac field, and when this frequency coincides with the mechanical resonance frequency, f r , of the material, the ribbon will resonate and provide increased response signal amplitudes.
  • the biasing field is provided by a ferromagnet with a higher coercivity than the target material present in the "target package".
  • the amplitude of the response signal, or voltage, from the target material increases through the duration of the exciting pulse (as dictated by inertia), and eventually reaches a stable, constant value if the exciting pulse lasts for a long enough time.
  • the peak-to -peak height of this stable amplitude is represented as V r in the Figure.
  • the term "ring down time” means the time interval during which the amplitude of response from the ribbon is reduced to about 10% of that amplitude extant when an exciting pulse applied to the ribbon is terminated, such time interval commencing at the instant of termination of the exciting pulse.
  • the ring down time, t r is approximately a linear function of the ribbon length, L; the longer the ribbon, the longer is the ring down time. Without being bound by any theory, it is believed that the increase in t r with increasing L is associated with the lowering of the mechanical resonance frequency in longer ribbons. The same amount of energy takes longer to dissipate at lower frequencies.
  • the magnitude of the response voltage sensed by a receiver is dependent on how that receiver is disposed within the system. For example, a receiver in a system requiring the insertion of an identification card into a slot will perceive a magnitude for V r that is different from that perceived by a receiver in a system designed for employment at the exit doors of a department store, even though identical target materials are used in both systems.
  • V r there are no requirements on the magnitude of V r as far as the choice of target material is concerned. It is, however, understood that the value for V r should be such that the response voltage is of sufficient strength to be detected by the receiver at the instant, during the ring down period, when the receiver "listens" to the target material. Henceforth, for the reasons detailed immediately above, no further reference to V r will be made in the description of this invention.
  • Table I lists the values for t r obtained from various metallic glass alloys that are outside the scope of this invention but which happen to lie within the scope of compositions claimed in the '489 and '490 patents. With the exception of the last named alloy, the ring down times for the alloys in this Table are short. This last named alloy is prone to the difficulties associated with the casting of alloys with high molybdenum contents.
  • the alloy Fe40Ni38Mo4B18 is unique in terms of its long ring down time. A lowering of the molybdenum content to make the alloy more economical to.produce invariably compromises the ring down time. It will be further understood from the Tables I to III that the long ring down times obtained in the alloys of this invention, with the stated combination of the specific elements, are much longer than the ring down times of previous target materials.
  • Glassy metal alloys in the Fe-Ni-Mo-B-Si-C family were rapidly quenched from the melt following the techniques taught by Narasimhan in U.S. Patent No. 4,142,571, the disclosure of which is hereby incorporated by reference thereto. All casts were made in a vacuum chamber, using 25 to 100 g melts. The resulting ribbons, typically 25 to 30 ⁇ m thick and about 6 mm wide, were determined to be free of significant crystallinity by x-ray diffractometry using Cu-K ⁇ radiation and differential scanning calorimetry. Each of the alloys was at least 70% glassy and, in many instances, the alloys were more than 90% glassy. Ribbons of these glassy metal alloys were strong, shiny, hard, and ductile.
  • Ribbon samples cut to about 38 mm in length, were used for the characterization of ring down times in the various alloys. This ribbon length is appropriate to a mechanical resonance frequency ranging from about 55 kHz to about 60 kHz in these alloys.
  • the biasing dc field and the driving ac field were obtained from two solenoids that were coaxially configured.
  • the biasing solenoid about 0.38 m in length, had a turn density of about 3400 turns/m, and the driving solenoid was about 0.3 m long with a turn density of about 1440 turns/m.
  • the sample was placed on the axis of these solenoids, at about the middle of their length.
  • the sample response was sensed through a pick-up coil comprising between about 100 and 120 turns of wire wound closely around the sample and covering the entire ribbon length.
  • the sample response (pick-up signal) and the driving ac signal were simultaneously monitored on an oscilloscope screen.
  • a pulse was sent through the exciting solenoid, which pulse contained a counted number of waves at the resonance frequency determined earlier as appropriate for the sample.
  • the number of waves, or, equivalently, the duration of the pulse was adjusted to be sufficient to ensure that the sample response had reached a stable value.
  • Adjustments to the driving frequency, and to the biasing field strength were also made, when necessary, to obtain a maximum sample response signal. Peak sample responses were obtained with the biasing field ranging from about 400 A/m to about 600 A/m, the driving frequency ranging from about 56 kHz to about 58 kHz, and the exciting pulse comprising between about 80 and 100 waves.
  • the traces on the oscilloscope screen were as schematically illustrated in the Figure.
  • the ring down time was determined as the time required for the sample response amplitude to reduce to 10% of the amplitude at the instant the exciting pulse was turned off.
  • Table IV lists the ring down times obtained from these 38 mm long as-cast metallic glass ribbons.
  • each of the alloys listed in Table IV showed good castability and had a ring down time of at least about 4.2 ms, which is relatively long as compared with alloys outside the scope of the invention.
  • those selected from the group consisting of sample Nos. 2, 4, 6, 7 and 10, having a ring down time of at least about 5 ms, are preferred.
  • Ribbons of selected alloys from the above Table were subject to simple stress relief anneals, i.e., low temperature anneals in the absence of externally imposed magnetic fields.
  • the anneal temperature ranged between about 473 K and 573 K, and the anneal time ranged between about 15 min. and 60 min. Ring down times from these annealed ribbons were found to be longer than in the corresponding as-cast ribbons.
  • the extent of increase was dependent on the chemical composition of the metallic glass and on the anneal conditions for a given alloy.
  • Other anneal conditions which may optimize the magnetomechanical coupling effects available in a metallic glass alloy ribbon, such as those including the presence of external fields applied along the ribbon width, can be employed to improve the resonance target response of the alloys of this invention.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Soft Magnetic Materials (AREA)
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Abstract

L'alliage de verres métalliques magnétiques décrit, qui se caractérise par un faible taux d'amortissement des oscillations de résonance mécanique, est approprié pour être utilisé dans des systèmes de surveillance d'objets à cibles incorporées utilisant la résonance mécanique de la cible. L'alliage a une composition représentée par la formule FeaNibMcBdSieCf, où M représente soit du molybdène soit du chrome, les éléments ''a'' à ''f'' sont compris dans des rapports atomiques, ''a'' étant compris entre environ 39 et environ 41 %, ''b'' entre 37 et environ 39 %, ''c'' entre 0 et environ 3 %, ''d'' entre environ 17 et environ 19 % et ''e'' et ''f'' entre 0 et environ 2 %, à condition que (i) seulement l'un des éléments ''c'', ''e'' et ''f'' peut être égal à 0, (ii) ''e'' ne peut pas être égal à 0 lorsque ''f'' n'est pas égal à 0 et (iii) ''f'' ne peut être égal à 0 que lorsque M représente Cr. Un ruban, un fil ou une feuille de cet alliage, ayant une résonance mécanique dont les fréquences sont comprises entre environ 55 kHz et environ 60 kHz, ce caractérisent par un temps de réduction d'amplitude de la résonance d'au moins 3 ms environ.

Claims (10)

  1. Un alliage magnétique de verre métallique qui est au moins vitreux à 70 %, ayant une composition décrite par la formule FeaNibMcBdSieCf, dans laquelle M est l'un des éléments molybdène ou chrome, "a" à "f" sont en atomes pour cent, "a" varie d' environ 39 à environ 41, "b" varie d' environ 37 à environ 39, "c" varie d' environ 0 à environ 3, "d" varie d' environ 17 à environ 19, "e" et "f"varient d' environ 0 à environ 2, avec les conditions que (i) seulement l' un des nombres "c" , "e" ou "f" peut être nul, (ii) "e" ne peut être nul si "f" n' est pas nul, et (iii) "f" peut être nul seulement quand M représente le Cr.
  2. Un alliage comme exposé selon la revendication 1, ayant la forme d'une bande qui présente une résonance mécanique dans un domaine de fréquences d'environ 55 kHz à environ 60 kHz, et ayant un temps de sonnerie decrescendo d'au moins 3 ms .
  3. L' alliage magnétique de la revendication 2, dans lequel le dit temps de sonnerie decrescendo est plus grand qu' environ 5 ms
  4. L' alliage magnétique de la revendication 2, dans lequel "e" ou "f" varient entre environ 0,5 et environ 2 .
  5. L' alliage magnétique de la revendication 2, dans lequel chacun des nombres "e" et "f" varie entre environ 0,5 et environ 1 .
  6. Dans un système de surveillance d' objet adapté à la détection d' un signal produit par la résonance mécanique d' une cible à l' intérieur d' un champ magnétique appliqué, l' amélioration dans laquelle la dite cible comprend au moins une bande de matériau ferromagnétique qui est au moins vitreux à 70 % , et a une composition décrite par la formule FeaNibMcBdSieCf , dans laquelle M est l'un des éléments molybdène ou chrome, "a" à "f" sont en atomes pour cent, "a" varie d'environ 39 à environ 41, "b" varie d' environ 37 à environ 39, "c" varie d' environ 0 à environ 3, "d" varie d' environ 1 7 à environ 19, "e" et "f"varient d' environ 0 à environ 2, avec les conditions que (i) seulement l' un des nombres "c" , "e" ou "f" peut être nul, (ii) "e" ne peut être nul si "f" est nul, et (iii) "f" peut être nul seulement quand M représente le Cr .
  7. Un système de surveillance d' objet comme décrit dans la revendication 6, dans lequel la dite bande est sélectionnée parmi le groupe constitué de ruban, fil et feuille .
  8. Un système de surveillance d' objet comme décrit dans la revendication 6, dans lequel la dite bande présente une résonance mécanique dans un domaine de fréquences d'environ 55 kHz à environ 60 kHz, et ayant un temps de sonnerie decrescendo d'au moins 3 ms .
  9. Un système de surveillance d' objet comme décrit dans la revendication 8, dans lequel "e" et "f" varient entre environ 0,5 et environ 1 .
  10. Un système de surveillance d' objet comme décrit dans la revendication 6, dans lequel la dite bande a une composition sélectionnée parmi le groupe constitué de Fe₄₀Ni₃₈Mo₂B₁₈Si₁C₁, Fe₄₀Ni₃₈Mo1,5B18,5Si₁C₁ , Fe₄₀Ni₃₈Mo₂B18,5Si₁C0,5 , Fe₄₀Ni₃₈Mo₂B18,5Si0,5C₁ et Fe₄₀Ni₃₈Mo₃B₁₇Si₁C₁.
EP89909913A 1988-09-26 1989-08-16 Alliages de verres metalliques pour systemes de surveillance d'objets a cibles incorporees utilisant la resonance mecanique de la cible Expired - Lifetime EP0435885B1 (fr)

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US24869988A 1988-09-26 1988-09-26
US248699 1988-09-26

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EP0435885B1 true EP0435885B1 (fr) 1993-08-04

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EP (1) EP0435885B1 (fr)
JP (1) JPH04500985A (fr)
CA (1) CA1341071C (fr)
DE (1) DE68908184T2 (fr)
DK (1) DK48791A (fr)
WO (1) WO1990003652A1 (fr)

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DE19653430A1 (de) * 1996-12-20 1999-04-01 Vacuumschmelze Gmbh Anzeigeelement für die Verwendung in einem magnetischen Warenüberwachungssystem
US6057766A (en) * 1997-02-14 2000-05-02 Sensormatic Electronics Corporation Iron-rich magnetostrictive element having optimized bias-field-dependent resonant frequency characteristic
TW374183B (en) * 1997-06-24 1999-11-11 Toshiba Corp Amorphous magnetic material and magnetic core using the same
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DE19732872C2 (de) 1997-07-30 2002-04-18 Vacuumschmelze Gmbh Anzeigeelement für die Verwendung in einem magnetischen Diebstahlsicherungssystem
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US6011475A (en) * 1997-11-12 2000-01-04 Vacuumschmelze Gmbh Method of annealing amorphous ribbons and marker for electronic article surveillance
US6254695B1 (en) * 1998-08-13 2001-07-03 Vacuumschmelze Gmbh Method employing tension control and lower-cost alloy composition annealing amorphous alloys with shorter annealing time
DE29823167U1 (de) * 1998-12-29 1999-04-08 Georg Siegel GmbH zur Verwertung von gewerblichen Schutzrechten, 59174 Kamen Warensicherungselement
US6359563B1 (en) * 1999-02-10 2002-03-19 Vacuumschmelze Gmbh ‘Magneto-acoustic marker for electronic article surveillance having reduced size and high signal amplitude’
US6645314B1 (en) 2000-10-02 2003-11-11 Vacuumschmelze Gmbh Amorphous alloys for magneto-acoustic markers in electronic article surveillance having reduced, low or zero co-content and method of annealing the same
JP4244123B2 (ja) 2002-08-20 2009-03-25 日立金属株式会社 レゾネータ
US9520219B2 (en) * 2006-06-06 2016-12-13 Owen Oil Tools Lp Retention member for perforating guns
DE102006047022B4 (de) 2006-10-02 2009-04-02 Vacuumschmelze Gmbh & Co. Kg Anzeigeelement für ein magnetisches Diebstahlsicherungssystem sowie Verfahren zu dessen Herstellung
US7432815B2 (en) 2006-10-05 2008-10-07 Vacuumschmelze Gmbh & Co. Kg Marker for a magnetic theft protection system and method for its production
JP6337994B1 (ja) * 2017-06-26 2018-06-06 Tdk株式会社 軟磁性合金および磁性部品

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JPH04500985A (ja) 1992-02-20
DK48791D0 (da) 1991-03-19
DE68908184D1 (de) 1993-09-09
WO1990003652A1 (fr) 1990-04-05
EP0435885A1 (fr) 1991-07-10
CA1341071C (fr) 2000-08-01
DK48791A (da) 1991-03-19
DE68908184T2 (de) 1993-11-25

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