Non-ferrous metals are defined as metals that do not contain which element?

Non-ferrous metals are classified as metals that do not contain iron. This is significant because the presence of iron usually leads to the classification of metals as ferrous, which can have different properties and applications compared to non-ferrous metals. Non-ferrous metals typically include aluminum, copper, lead, nickel, and zinc, among others.

The absence of iron in non-ferrous metals contributes to their resistance to corrosion, lighter weight, and better conductivity in specific applications. This distinction is crucial for industries that require specific properties from metals for manufacturing and other processes.

In contrast, the other elements listed—gold, copper, and nickel—can all be included in non-ferrous classifications as they do not contain iron. Hence, they do not influence the definition of non-ferrous metals by having iron content.