Supermalloy

Supermalloy is a nickel–iron alloy known for its very high magnetic permeability and very low coercivity, making it suitable for soft magnetic applications. The composition is typically around 80 percent nickel and 20 percent iron, with small additions of other elements such as copper and molybdenum to tailor magnetic properties and reduce losses. Exact formulations vary by producer.

Key properties include extremely high initial permeability, low coercive force, and low core losses, especially at audio and RF frequencies. The alloy also has relatively high electrical resistivity for a nickel–iron system, which helps minimize eddy current losses in rapidly varying magnetic fields. To optimize permeability and mechanical properties, it is often annealed under controlled conditions, yielding a magnetically soft material with low magnetostriction.

Applications of supermalloy center on magnetic cores and shielding. It is used in transformer and inductor cores to increase inductance and efficiency, in magnetic shielding for sensitive electronics, and in read/write heads for magnetic recording. It is commonly considered a specialized variant of permalloy, chosen for improved high-frequency performance and reduced losses.

Performance depends on the exact composition and heat treatment, but supermalloy is valued for combining high permeability with low coercivity and low core losses. Its characteristics make it a versatile material for both RF and power magnetic applications where efficient, soft magnetic behavior is required.