Corrosion is the **gradual destruction of metals** by chemical or electrochemical reaction, often forming oxides or salts.

**Rusting** is the corrosion of iron, forming **iron oxide (Fe₂O₃·xH₂O)**.

**Both water and oxygen** (from air) are required for the **electrochemical rusting** of iron.

**Painting** forms a protective layer and **prevents contact with air and moisture**, reducing corrosion.

**Galvanization** is the process of **coating iron with a layer of zinc** to prevent corrosion.

In corrosion, the **metal loses electrons** (is oxidized), acting as a **reducing agent**.

**Gold** is a **noble metal** and is highly resistant to corrosion.

**Salt water** acts as an electrolyte, enhancing the **electrochemical corrosion** process.

**Aluminum forms a protective Al₂O₃ layer** that prevents further oxidation.

**Alloying** (e.g., stainless steel) changes the metal's composition to make it more **corrosion-resistant**.