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US 6,254,695 B1Granted
Method employing tension control and lower-cost alloy composition annealing amorphous alloys with shorter annealing time
AssigneeVacuumschmelze GmbH & Co. KG
InventorsGiselher Herzer, Robert Schulz
Life of this patent
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Abstract
A ferromagnetic resonator for use in a marker in a magnetomechanical electronic article surveillance system has improved properties and can be manufactured at higher annealing speeds and reduced raw material cost by virtue of being continuously annealed in the simultaneous presence of a magnetic field perpendicular to the ribbon axis and a tensile stress applied along the ribbon axis and by providing an amorphous magnetic alloy containing iron, cobalt and nickel in which the portion of iron is more than about 15 at % and less than about 30 at %.
Claims34
A method for annealing an 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 amorphous alloy article in a zone of elevated temperature while subjecting said amorphous alloy article to tensile stress along said longitudinal axis and while subjecting said amorphous alloy article to a magnetic field oriented substantially perpendicularly to said longitudinal axis, to produce an annealed amorphous alloy article having a plurality of characteristics;
- (c) selecting said alloy composition to comprise iron, cobalt and nickel having an iron content of more than about 15 at % and less than about 30 at % so that the annealed amorphous alloy article has, among said characteristics, an induced magnetic easy plane perpendicular to said longitudinal axis due to said tensile stress which is superimposed to the magnetic easy axis direction induced by said magnetic fields;
- (d) monitoring at least one of said characteristics of said annealed amorphous alloy article upon exiting said zone of elevated temperature;
- and
- (e) adjusting said tensile stress to which said amorphous alloy article is subjected in said zone of elevated temperature dependent on the final characteristic which is monitored.
3 more elements
A method for manufacturing a marker for an electronic article surveillance system comprising the steps of:
- (a) providing an unannealed amorphous alloy article having an alloy composition and a longitudinal axis;
- (b) disposing said amorphous alloy article in a zone of elevated temperature while subjecting said alloy article to tensile stress along said longitudinal axis and while subjecting said amorphous alloy article to a magnetic field oriented substantially perpendicularly to said longitudinal axis, to produce an annealed amorphous alloy article having a plurality of characteristics;
- (c) selecting said alloy composition to comprise iron, cobalt and nickel with an iron content of more than 15 at % and less than 30 at %, and so that the annealed amorphous alloy article has, among said characteristics, an induced magnetic easy plane perpendicular to said longitudinal axis due to said tensile stress which is superimposed to the magnetic easy axis direction inducted by said magnetic field;
- (d) monitoring at least one of said characteristics of said annealed amorphous alloy article upon exiting said zone of elevated temperature;
- (e) adjusting said tensile stress to which said amorphous alloy article is subjected in said zone of elevated temperature dependent on the final characteristic which is monitored;
- (f) providing a demagnetizable ferromagnetic element which produces a magnetic bias field;
- (g) cutting a piece of said annealed amorphous alloy article to form a resonator;
- and
- (f) enclosing said resonator and said ferromagnetic element in a housing with said resonator disposed in said magnetic bias field.
6 more elements
A method for annealing an 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 amorphous alloy article in a zone of elevated temperature while subjecting said amorphous alloy article to tensile stress along said longitudinal axis and while subjecting said amorphous alloy article to a magnetic field oriented substantially perpendicularly to said longitudinal axis, to produce an annealed amorphous alloy article having a plurality of characteristics;
- and
- (c) selecting said alloy composition to comprise iron with an iron content of more than about 45 at %, so that the annealed amorphous alloy article has, among said characteristics, a substantial change of Young's modulus in the presence of a magnetic bias field;
- (d) monitoring at least one of said characteristics of said annealed amorphous alloy article upon exiting said zone of elevated temperature;
- and
- (e) adjusting said tensile stress to which said amorphous alloy article is subjected in said zone of elevated temperature dependent on the final characteristic which is monitored.
4 more elements
Dependencies are inferred from the claim text.