High Magnetic Permeability Alloys Hardperm in the Ni-Fe-Ta-Mo System*

Starting materials used were 99.8% pure nickel, 99.9% pure iron, 99.9% pure tantalum, and 99.9% pure molybdenum. The materials in a total weight of 500g were melted with a high-frequency induction furnace in vacuum. The melt was poured into an iron mold with an opening of 20mm diameter and 150mm length. After forging, the ingot was reduced to a thin plate 0.3mm in thickness by rolling and a wire 2mm in diameter by swaging and drawing. A ring-shaped plate 33mm in inner diameter and 45mm in outer diameter was stamped out from the plate. A rod 100mm long was cut from the wire. Both the ring-