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US 6,645,314 B1Granted
Amorphous alloys for magneto-acoustic markers in electronic article surveillance having reduced, low or zero co-content and method of annealing the same
AssigneesVacuumschmelze GmbH & Co. KG, Sensormatic Electronics Corporation
InventorsGiselher Herzer, Nen-Chin Liu
Life of this patent
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Abstract
A ferromagnetic resonator for use in a marker in a magnetomechanical electronic article surveillance system is manufactured at reduced cost by being continuously annealed with a tensile stress applied along the ribbon axis and by providing an amorphous magnetic alloy containing iron, cobalt and nickel and in which the portion of cobalt is less than about 4 at %.
Claims14
A method of annealing a magnetic amorphous alloy article comprising the steps of:
- (a) providing an unannealed amorphous alloy article having an alloy composition and a longitudinal axis;
- (b) disposing said unannealed amorphous alloy article in a zone of elevated temperature while subjecting said amorphous alloy article to a tensile force along said longitudinal axis, and without a magnetic field other than an ambient magnetic field, to produce an annealed article;
- and
- (c) selecting said alloy composition to comprise at least iron and nickel and at least one element from the group consisting of V, Nb, Ta, Cr, Mo and W so that the annealed article has an induced magnetic easy plane perpendicular to said longitudinal axis due to a combination of said composition, said temperature and said tensile stress.
1 more element
A method of annealing a magnetic amorphous alloy article comprising the steps of:
- (a) providing an unannealed amorphous alloy ribbon having a width between about 1 mm and about 14 mm and a thickness between about 15 μm and about 40 μm
- (b) disposing said unannealed amorphous alloy article in a zone of elevated temperature while subjecting said amorphous alloy to a tensile force along said longitudinal axis, and without a magnetic fields other than an ambient magnetic field, to produce an annealed article;
- and
- (c) selecting said alloy composition to comprise at least iron and nickel and at least one element from the group consisting of V, Nb, Ta, Cr, Mo and W so that the annealed article has an induced magnetic easy plane perpendicular to said longitudinal axis due to said tensile stress selecting said alloy composition such that said annealed article has a ductility allowing said annealed article to be cut into discrete elongated strips.
1 more element
A method of making a marker for use in magnetomechanical electronic article surveillance system, comprising the steps of:
- (a) providing at least one unannealed amorphous alloy article having an alloy composition and a longitudinal axis;
- (b) disposing said at least one unannealed amorphous alloy article in a zone of elevated temperature while subjecting said at least one amorphous alloy article to a tensile force along said longitudinal axis, and without a magnetic field other than an ambient magnetic field to produce at least one annealed article;
- (c) selecting said alloy composition to comprise at least iron and nickel and at least one element from the group consisting of V, Nb, Ta, Cr, Mo and W to produce in said at least one annealed article, in combination with said temperature and said tensile stress, an induced magnetic easy plane perpendicular to said longitudinal axis due to said tensile stress;
- (d) placing said at least one annealed article adjacent a magnetized ferromagnetic bias element which produces a bias magnetic field;
- and
- (e) encapsulating said at least one annealed article and said bias element in a housing.
3 more elements
A method of annealing and amorphous alloy article comprising the steps of:
- providing an unannealed amorphous alloy article having a longitudinal axis and an alloy composition selected to produce a stress-induced anisotropy greater than 0.04 Oe/MPa in said amorphous alloy article when said amorphous alloy article is annealed for six seconds at 360° C. and selected to produce a magnetic easy axis perpendicular to said longitudinal axis when a tensile stress is applied along said longitudinal axis during annealing;
- and
- disposing said amorphous alloy article in a zone of elevated temperature, and without a magnetic field other than an ambient magnetic field, while subjecting said amorphous alloy article to a tensile force along said longitudinal axis to produce said anisotropy greater than 0.04 Oe/MPa and said magnetic easy axis in said amorphous alloy article.
Dependencies are inferred from the claim text.