Alloys

Alloys are mixtures of metals with other elements, designed to enhance the properties of pure metals. They are widely used in industry and daily life due to their superior strength, hardness, and resistance to corrosion.

What is an alloy?

• An alloy is a mixture of a metal with other elements (which can be metals or non-metals).

• Alloys are created to improve the properties of pure metals, such as strength, hardness, and resistance to corrosion.

Examples of Alloys

• Brass: A mixture of copper and zinc.

  • Use: Decorative items, musical instruments, and plumbing fixtures due to its malleability and resistance to corrosion.

• Stainless Steel: A mixture of iron with other elements such as chromium, nickel, and carbon.

  • Use: Cutlery, medical instruments, and construction materials due to its hardness, strength, and resistance to rusting.

• Bronze: A mixture of copper and tin.

  • Use: Statues and medals due to its strength and resistance to wear.

Advantages of alloys over pure metals

• Alloys are often harder and stronger than the pure metals they are made from.

• They are more useful in practical applications because their enhanced properties make them better suited to demanding environments.

• Example: Stainless steel is much harder and more rust-resistant than pure iron, making it ideal for use in cutlery and kitchen utensils.

Why alloys are harder and stronger than pure metals

• Pure metals: Atoms are the same size, arranged in regular layers. These layers can slide over each other, making the metal soft and malleable.

• Alloys: The atoms of different sizes disrupt the regular arrangement of layers. This disruption prevents the layers from sliding easily, increasing hardness and strength.

• Example: Stainless steel is harder than pure iron because the addition of chromium and nickel creates a more rigid structure.

Arrangement of ions in a pure metal (left) and an alloy (right)

Identifying alloys