Characteristics of Permalloy and its difference from pig iron

Permalloy, as an important Soft Magnetic alloy material, has many unique properties that make it significantly different from common ferromagnetic materials such as pig iron.

When distinguishing Permalloy from pig iron, an intuitive and simple method is to use a magnetic probe to test their magnetic permeability. Magnetic permeability is an important indicator to measure the material’s ability to respond to a magnetic field. Generally speaking, Permalloy exhibits extremely high magnetic permeability, and its value is usually above 100,000, which indicates that it is extremely sensitive to changes in the magnetic field and can quickly and effectively conduct magnetic lines of force. In contrast, the magnetic permeability of pig iron is much lower, generally less than 20,000, which means that its ability to respond in a magnetic field is relatively weak.

The preparation process of Permalloy is also quite delicate. It is usually melted in a vacuum induction furnace to ensure the uniformity and purity of the alloy composition. Subsequently, after a series of hot and cold plastic deformation treatments, such as rolling, drawing, etc., Permalloy is made into finished products of various shapes and sizes, such as cold-rolled strips, cold-drawn wires or hot-rolled (forged) plates and bars. These finished materials have a wide range of applications in the fields of electronics and electrical, such as for the manufacture of audio transformers, mutual inductors, magnetic amplifiers, magnetic modulators, chokes, and audio heads and other key components.

The reason why Permalloy can be widely used in these fields is due to its excellent soft magnetic properties. Specifically, its initial magnetic permeability μi is between 36.5 and 135 mH/m, which means that when the magnetic field begins to act, Permalloy can quickly reach a higher magnetic permeability state. At the same time, its maximum magnetic permeability μm is as high as 125 to 375 mH/m, showing excellent magnetic conductivity under strong magnetic fields. In addition, the coercive force of Permalloy is extremely low, only 0.8 A/m, which means that it can quickly return to a non-magnetic state after the external magnetic field is removed, and has good hysteresis loop characteristics. Finally, the resistivity ρ of Permalloy is between 60 and 85 μΩ·cm. This moderate resistivity helps to reduce eddy current losses and improve the energy efficiency of the material.

In summary, Permalloy plays an irreplaceable role in the fields of electronics and electrical engineering with its unique magnetic permeability, excellent soft magnetic properties and sophisticated preparation technology.