THE PROPERTIES OF SUB-20-MICRON PERMALLOY FIBER FORMED BY MELT EXTRACTION

Fibers of Permalloy of different compositions have been manufactured in diameters from 5-20-mu using a technique of melt-extraction. The molten material is raised on the edge of a sharpened rotating molybdenum wheel whose tangential velocity is typically about 60 ms-1. The surface of fibers is free formed and is almost without defects. The radial cooling and high quenching rates result in a unique crystalline and magnetic microstructure. The fibers show outstanding soft magnetic properties and require no annealing to optimize performance. They also exhibit strong resistance to degradation under mechanical stress, and are especially attractive for sensor applications.