Fe-based amorphous transformer magnetic core, production method therefor, and transformer

1. An Fe-based amorphous transformer magnetic core formed by stacking Fe-based amorphous alloy thin strips and satisfying the following (1) to (3) in a direct current B-H curve measured by applying a magnetic field of 80 A/m to the magnetic core:

B80≧1.1 T  (1)

0.5T≦Br≦0.7 T  (2)

B80−Br≧0.6 T  (3)

wherein B80 represents a magnetic flux density (T) obtained when magnetization is performed in the magnetic field of 80 A/m, and Br represents a residual magnetic flux density (T) obtained when a magnetic field is changed to 0 A/m after magnetization is performed in a magnetic field of 80 A/m, and wherein an alloy of the Fe-based amorphous alloy thin strips is alloy comprising 2 atomic percent to 13 atomic percent of Si, 8 atomic percent to 16 atomic percent of B, and not more than 3 atomic percent of C with the balance consisting of Fe and unavoidable impurities.

2. A transformer comprising:

the Fe-based amorphous transformer magnetic core according to claim 1 ; and

at least a pair of conductive wires wound around the Fe-based amorphous transformer magnetic core.

3. The transformer according to claim 2 for connection to an output side of an inverter.

4. A method of manufacturing the Fe-based amorphous transformer magnetic core according to claim 1 , comprising:

stacking Fe-based amorphous alloy thin strips to form a layered material; and

heat-treating the layered material in a magnetic field of 0 A/m at a holding temperature set to be more than 300° C. but not more than a temperature that is 150° C. less than a crystallization starting temperature of the amorphous alloy for a holding time set to be not less than 1 hour but not more than 6 hours.