Iron-Nickel is an alloy primarily composed of iron and nickel, typically containing about 75% iron and 25% nickel. This combination enhances the material's strength, ductility, and resistance to corrosion, making it useful in various applications, including aerospace and electronics. One of the most notable forms of iron-nickel alloy is Invar, known for its low thermal expansion properties. This characteristic makes it ideal for precision instruments and components that require stability under temperature changes, such as in scientific instruments and watchmaking.