PRODUCTION OF EXTREMELY THIN SOFT MAGNETIC ALLOY STRIP, EXTREMELY THIN SOFT MAGNETIC ALLOY STRIP AND MAGNETIC CORE USING THE SAME, ELECTRONIC DEVICE INCORPORATED WITH MAGNETIC CORE THEREOF AND APPARATUS FOR PRODUCING THIN SOFT MAGNETIC ALLOY STRIP

摘要

PURPOSE:To produce the amorphous or superfine crystalline alloy thin film having excellent soft magnetic characteristics in a high-frequency region by injecting the melt of a Co-based alloy and Fe-based alloy having specific compsns. onto a cooling roll rotating at high speed under vacuum. CONSTITUTION:A crucible 30 having an induction heating coil 34 is placed in a vessel 10 kept under =1X10-4Torr vacuum degree. The melt of the Co-based alloy or Fe-based alloy having the compsns. expressed by formula I or formula II is put therein. The melt is injected from the nozzle 32 of the crucible 30 under 0.015 to 0.025kg/cm2 injection pressure onto the surface 22 of the metallic cooling roll 20 made of Cu, etc., rotating at the high speed of 20 to 50m/sec circumferential speed and is rapidly cooled and solidified to produce the Co- based amorphous alloy thin film or Fe-based superfine crystalline alloy sheet 50 having 4.0mum thickness. The length on the short side in parallel with the rotating direction of the cooling roll 20 in the rectangular injection port of the nozzle 32 is specified to 0.07 to 0.13mm and the distance between the nozzle tip and the roll surface 22 is specified to 0.05 to 0.20mm. The resulted alloy sheet 50 is heat-treated at the crystallization temp. to the Curie temp.