System and method for treating an amorphous alloy ribbon

Abstract

A method and a system for continuously in-line annealing a forwarding ferromagnetic amorphous alloy ribbon in a curved shape to improve its magnetic properties without causing the ribbon to become brittle and which operates at significant high ribbon feeding rates. The amorphous alloy ribbon is fed forward, tensioned and guided along a path at a preset feeding rate and is heated at a point along the path at a rate greater than 10 3 ° C./sec to a temperature to initiate a thermal treatment. Then the ribbon is initially cooled at a rate greater than 10 3 ° C./sec until the thermal treatment ends. During the thermal treatment, a series of mechanical constraints is applied on the ribbon until the amorphous alloy ribbon adopts a specific shape at rest after the thermal treatment is ended. After the initial cooling, the amorphous alloy ribbon is subsequently cooled at a sufficient rate to a temperature that will preserve the specific shape.

1 . A heat-treated iron-based amorphous alloy ribbon, where said ribbon is ductile at normal room temperature, and wherein upon stacking or rolling up said ribbon to form a core, said ribbon has a B 80  greater than 1.3 Tesla and a B 80 /B sat  that is greater than 0.80. 
     
     
         2 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , wherein the ribbon is completely ductile at a temperature greater than normal room temperature. 
     
     
         3 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , having at least one side coated with a dielectric material. 
     
     
         4 . The heat-treated iron-based amorphous alloy ribbon according to  claim 3 , wherein the dielectric material is an organic dielectric material. 
     
     
         5 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , having at least one side coated with a binder. 
     
     
         6 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , wherein the ribbon is cuttable or punchable in segments having predetermined lengths or outlines. 
     
     
         7 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , wherein upon stacking and rolling up said ribbon to form a core, the ribbon has a core loss lower than 0.25 W/kg at 60 Hz at a magnetic induction of 1.3 Tesla. 
     
     
         8 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , wherein the ribbon is heat-treated by in-line annealing at a temperature to perform a thermal treatment without reaching the onset of crystallization. 
     
     
         9 . The heat-treated iron-based amorphous alloy ribbon according to  claim 8 , wherein the ribbon is bent into a series of different configurations during said thermal treatment until the ribbon adopts a specific shape at rest after said thermal treatment. 
     
     
         10 . The heat-treated iron-based amorphous alloy ribbon according to  claim 9 , wherein the thermal treatment is ended by cooling said ribbon at a temperature rate greater than 10 3 ° C./sec. 
     
     
         11 . The heat-treated iron-based amorphous alloy ribbon according to  claim 10 , wherein the thermal treatment is initiated by heating said ribbon at a temperature rate greater than 10 3 ° C./sec. 
     
     
         12 . The heat-treated iron-based amorphous alloy ribbon according to  claim 8 , wherein the temperature to perform the thermal treatment is greater than 425° C. 
     
     
         13 . The heat-treated iron-based amorphous alloy ribbon according to  claim 8 , wherein the thermal treatment is performed during a period of time that is less than one tenth of a second. 
     
     
         14 . The heat-treated iron-based amorphous alloy ribbon according to  claim 8 , wherein the ribbon is heat-treated by in-line annealing at a ribbon feeding rate greater than 1 m/sec. 
     
     
         15 . The heat-treated iron-based amorphous alloy ribbon according to  claim 1 , wherein the alloy comprises a nominal chemical composition Fe a B b Si c C d  where 80<a<84, 8<b<18, 0<c≦5 and 0<d≦3, numbers being in atomic percent, with incidental impurities. 
     
     
         16 . The heat-treated iron-based amorphous alloy ribbon according to  claim 15 , wherein upon stacking or rolling up said ribbon to form a core, the ribbon has a core loss lower than 0.25 W/kg at 60 Hz at a magnetic induction of 1.5 Tesla.