Ferrometal

Ferrometal is a term sometimes used to describe metals and metal alloys that exhibit ferromagnetism, the strong, cooperative alignment of electron spins due to exchange interactions. In mainstream materials science, these materials are typically referred to as ferromagnetic metals or ferromagnetic alloys. Common examples include elemental iron and its alloys (steel and cast iron), as well as the pure elements nickel and cobalt, and related iron-nickel or iron-cobalt compositions. Ferrometals can develop spontaneous magnetization below a characteristic Curie temperature and lose permanent magnetization above it, becoming paramagnetic.

Key properties include magnetic domains, hysteresis, saturation magnetization, and magnetic anisotropy. The Curie temperatures are material-specific: iron about 770°C, nickel about 358°C, cobalt about 1123°C. Magnetic behavior is influenced by composition, microstructure, temperature, and mechanical processing. Alloying elements such as silicon, chromium, nickel, and others are used to tailor permeability, coercivity, and remanence. Soft ferrometals (low coercivity) are optimized for transformer cores and electromagnetic devices, while hard ferrometals or specialized alloys provide permanent magnets for motors, speakers, and data storage.

Processing and durability considerations affect performance. Ferrometals can oxidize or corrode, especially at elevated temperatures or in harsh environments; corrosion-resistant variants (such as stainless steels) incorporate chromium or other alloying elements. Temperature sensitivity near the Curie point and magnetic aging are also considerations in design and application.