IRON-BASE AMORPHOUS ALLOY EXCELLENT IN SURFACE CHARACTERISTIC AND MAGNETIC PROPERTY

摘要

PROBLEM TO BE SOLVED: To stably obtain excellent iron loss characteristic even in the case of an Fe-B-Si amorphous alloy of low boron content by regulating the area ratio of air pockets at the roll face side surface for forming an amorphous alloy obtained by rapid solidification by the use of a cooling roll to a specific value or below. ;SOLUTION: The area ratio of air pockets is ≤20%, preferably ≤10%. The amorphous alloy is a low-boron Fe-B-Si amorphous alloy containing 6 to 10 atomic % B. The air pockets (10 to 20 μm in diameter, 1 to 3 μm in depth) are generated by air inclusion at the time of single roll rapid cooling, and cooling velocity becomes decreased because these positions are not in contact with the roll and microcrystallization is started from these positions. The influence of irregularities, etc. caused by transfer of roll marks present at the surface of the resulting ribbon, on magnetic properties is minimal. By reducing the ratio of the air pockets, magnetic properties comparable to those of a high-boron amorphous alloy can be obtained.;COPYRIGHT: (C)2000,JPO