What defines ferrous materials?

Ferrous materials are specifically defined as those that are based on iron. This classification includes both pure iron and various iron alloys, such as steel. The presence of iron is the primary characteristic that categorizes these materials as ferrous. They typically possess properties such as high tensile strength and resistance to deformation, which make them suitable for a wide range of applications, especially in construction and manufacturing.

The other options refer to different categories of materials. For instance, materials containing aluminum are classified as non-ferrous, as are copper-based alloys, which are also distinguished by their primary metal content. Plastic-based materials belong to a completely different category altogether, and they do not contain metal. Therefore, the defining aspect of ferrous materials is their iron content, making the identification straightforward and critical for various industrial applications.